# Running tests on the WF-139. Interesting results. A must read for WF-139 users.



## mdocod (Aug 12, 2008)

I have taken my "conclusions" from later in this thread and decided to edited them right into the top of the thread for all to see more clearly:

*From Post #60 in this thread:*

*All WF-139 chargers, regardless of what "version" it is. Use a Constant Current only charging algorithm that can reach *charging* voltages of ~4.25-4.35+V during charging depending on the capacity of the cell being charged. *
Charging a small unprotected cell in with this type of charger could cause charging voltages of 4.4V or higher to be reached in theory.
Most would agree that this charging method does not follow most li-ion manufactures recommendations for charging, and will probably reduce the life of the cell.
Charging a small unprotected cell (like a RCR123) in this charger, could come with increased risk of fire/explosion. 

The Older WF-139 chargers, will measure ~10-12V open circuit, and will continue to trickle charge cells after the charge has been terminated. This could lead to fire/explosion if left unattended for long periods of time.
If the charge is terminated by the cells protection, which is very common when protected RCR123 or similar size cells are charged in this charger, the cell will not be trickle charged because the cells protection will hold the circuit closed after it has tripped.

Newer WF-139 chargers, will measure ~5V open circuit, and will not trickle charge after termination.

-----------------------------------------------------------------

Video is of a pair of 3.7V protected AW brand RCR123s on a WF-139 charger.

When voltage got to around 4.30V I had to grab the camera. 

http://www.youtube.com/watch?v=w05TzgYHayY <watch this video.

This amazed me.

Ever wonder what's going on behind the scene with your WF-139? 

I decided to run some tests to explain some of the weird behavior of this charger.

MANY people have reported that when charging AW RCR123s in this charger, they "terminate" at around 4.16V. I have speculated that the charge was being terminated by the cell at a voltage much higher than this, and then settling down to 4.16V without a supply voltage, I was correct. This video not only proves that (notice the voltage jumps to the open circuit voltage of the WF-139 when the charge "terminates"), but also that during the charge, the WF-139 is indeed holding the cell in a state of over-charge. 

Here's a picture of the cell moments after charge was terminated:






THE WF-139 DOES NOT APPEAR TO HAVE A CV STAGE AT ALL.

The WF-139 is holding a CC stage until the cell is somewhere in the 4.3X volt range, and then, terminating with the expected result of the cell settling to around 4.20V. This charge method is not considered terribly bad, but it's not terribly good either. 

If you notice in the video, the voltage reading fluctuates, it "dips" down during the charge every few seconds. I believe the charger takes a "reading" of the cell voltage with the charge stopped every few seconds to see how much farther it needs to go to get to around 4.20V open circuit. My multi-meter is probably not showing how far down the cell voltage is compared with the charge voltage on these little "blips" because it's not responsive enough to catch it, so to speak. It's probably "RMSing" the value a bit so we're not seeing the whole picture.

On a smaller cell, the voltage is ramping up a lot faster than on larger cells, all the way to the point of tripping the PCB before it even makes it to 4.20V open circuit. This is why the smaller protected cells are not coming off the charger at 4.20+V like larger cells often do with this charger, the PCB is not only terminating the charge, it is also holding the circuit open until the input voltage is removed, this prevents the WF-139 from being able to do it's famous over-charge via trickle method.

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More testing Observations:

On a pair of AW brand protected 17500s:
Charge voltage was at 4.31V when the charger terminated the charge and voltage dropped to 4.22V still on the charger. ~20 minutes later this had settled to 4.21V. I'm going to leave this on the charger with the volt-meter in place for another hour or more and try to capture the voltage rising as I expect it to from trickle charge.

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More test results and pictures to follow.

Eric


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## lctorana (Aug 12, 2008)

Wow.

So the UF-139 will charge the cells quite nicely, but looking at SilverFox's ready reckoner, it will shorten the cell life quite drastically _whether we leave the cells on the charger after the light turns green or not_.

Lesson #2
Small unprotected cells really, really, would not like the UF-139.


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## Black Rose (Aug 12, 2008)

Open circuit voltage at termination...


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## mdocod (Aug 12, 2008)

The ~11V reading is fine, it's the open circuit voltage of the charger and the cell is NOT seeing that voltage since the PCB has severed the circuit, it's nothing to be concerned about.


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## PhantomPhoton (Aug 12, 2008)

Thanks, I haven't even thought to poke around like that yet to monitor what was going on there. Doesn't surprise me that it doesn't use a CV being so cheap.

I've been using the 139 charger for a year and a half now, but only light usage on my LiIon cells. The only problem I've had with a cell is a relatively new AW RCR123 not wanting to charge anymore. I suspect it was a cell problem and not a charger problem though as it's brother still works fine.


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## Black Rose (Aug 12, 2008)

mdocod said:


> The ~11V reading is fine, it's the open circuit voltage of the charger and the cell is NOT seeing that voltage since the PCB has severed the circuit, it's nothing to be concerned about.


If the charger is rated to have an output of 4.2V (450 mA), why does it jump up to 10 - 11 volts right after termination? 

I watched the video again, and noticed that the open circuit voltage stays high from around 30 seconds until the end of the video. 
I would have expected it to drop once the battery indicated "no more".


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## mdocod (Aug 12, 2008)

The 11V reading is what you would get with no cell in place but with the charger plugged in. When the circuit has no load, it happens to have an output voltage around 11V. Once the PCB of the cell tripped, the voltage of the charger under no load becomes present. 

Like when a CR123 is fresh from a package, it reads 3.2V, but when it is under the load of a P91, it's ~2.2V. Same type of thing. 

Often times li-ion chargers for consumer style "loose" protected cells are designed to have this high open circuit voltage to re-set PCBs that have tripped off due to over-discharge. The 11V of the WF-139 may be a bit excessive, but most PCBs I'm aware of in good quality cells can handle up to around 12V without a problem.


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## Mr Happy (Aug 12, 2008)

I might perhaps take a less favorable view and suggest that the high voltage is typical of a constant current circuit with a high resistance load. In such cases, the voltage will naturally rise to the maximum.

It seems to me it would be much better if the voltage didn't rise above 4.2 V under any circumstances.


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## zipplet (Aug 13, 2008)

This is awful - I thought the nano charger was bad (4.26V open circuit, so it has the potential to charge that high with trickle charging) but this WF thing looks like a piece of junk after seeing these tests.


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## McLux (Aug 13, 2008)

I am using a DIY li-ion charger for a few years now, with a voltage regulator, adjusted at 4.20 volts, and a current limiter @ approx. 1 A. The open circuit voltage is always 4.20 volt, I am wondering why the manufacturers don't make their devices that way.
My charger did't stop automaticly (I use a timer for safety), but after 4 hours, the current is only a few mA anymore, so the battery stops charging by itself.


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## zipplet (Aug 13, 2008)

I wonder the same thing as I'm currently designing my own charger. Infact, in my post here I say the exact same thing as you. It costs nothing to do, but they don't do it.


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## WildChild (Aug 13, 2008)

This is why I trashed mine when I saw that! Mine was going to around 4.29v at the end of the charge and the two charge slot gave different readings. They were not charging the batteries at the same level at all. No problem since I switched to the Pila IBC. And at the end of the charge process, I never read over 4.20V on the terminals.


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## harddrive (Aug 13, 2008)

Makes you feel guilty about using the WF139. I also use the WF-137 for 18650 and suspect it is no better. 

I think I might have to get a Pila IBC but I can't find one for less than about $70 USD delivered to Australia.


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## zipplet (Aug 13, 2008)

This entire business is why im building my own charger. It's actually quite simple to do and easier than building a -dV nicd/nimh charger but I wouldn't recommend it to most people because the potential for something to go wrong is high.

Another member here is doing the same but I can't remember what his thread was called so I can't find it...


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## DM51 (Aug 13, 2008)

Good thread, and an excellent idea to do a video of it. 

This is the main reason I stopped using the WF-139 some while ago - I got suspicious of the high voltage of cells right off the charger. They soon settled back down again, but still >4.20V, too high.

To rely on the cell's over-charge protection for termination is asking for trouble. It is not safe practice, and the fact that there is not a proper CV phase is not good for the cell.


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## Ray1968 (Aug 13, 2008)

Interesting. I'll try the same test tonight and post the results.


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## JNewell (Aug 13, 2008)

Ehmmm...thanks....so....

1. Should I junk my WF139?

2. What should I replace it with?

Tks....


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## Tohuwabohu (Aug 13, 2008)

There is quite a lot of information on several cheap chargers including the Ultrafire WF-139 on this japanese page. 
I can't read japanese and the Google translation is not very helpful but there are a lot of interesting graphs and circuit details on that page. 

I don't have the WF-139 but I have the RCR123 version of the Ulrafire WF-138 which uses a very simalar curcuit.
With most of my protected RCR123's the charger will terminate the charge, but with some the protection circuit of the cell will kick in. If anybody is interested I could supply some scope graphs of the charging process.
I have ordered the Pila IBC and thought of comparing it to the WF-138 when it arrives.

The absenece of the CV stage in the charging process may not be good for the cell but it also has an advantage: the total charging time is shorter.

The HXY-042V2000A mentioned on the japanes page and also recommended in the german Messerforum.net could be a cheap and good alternative to the WF-139.
But, as often with this cheap stuff, you can't be sure what you get. I ordered the single cell version from KD an got an identical looking charger from another manufacturer with a lot worse build quality and lower charging current. That was the final reason for me to order the Pila IBC.


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## geek4christ (Aug 13, 2008)

Excellent detective work, MD. Thanks for doing these tests. I hope AW will consider offering a better charger in the future. A cheap charger at the expense of greatly reduced cycle life is just not a good trade-off IMHO.

One alternative (other than the Pila IBC) that I don't see mentioned very often is an affordable hobby charger like the Great Planes PolyCharge or the Apache 2020 which retail for around $23 and $30 respectively. All you need is one of those chargers, a cheap 12v power source (an old PC power supply can be used for this with a little modification) and some way to get the charging leads connected to the cells. I don't have either of those chargers, but they seem like very workable solutions.

Drawbacks that I see to going with a low cost pack charger:

Added cost of power supply or effort in building one from a PC power supply
Can't charge two cells independently
Must be careful to not set the charger to 2s or 3s if charging a single li-ion cell (although the PolyCharge has a safety mechanism that won't allow you to do that)
Cost is getting close to the Pila IBC anyway when you include shipping
Have to make a clamp or wire up a bay or use magnets to contact the loose li-ion cells
Benefits:

Selectable charge rate, so you can safely charge a wider variety of cells (10440 all the way to 18650)
Proven reliability of the products
Can run off 12v car battery when away from home without an extra adapter of any sort
Reputable dealers offer good warranties
Proper CC/CV algorithm and termination voltage unlike the UF-139
So that's my perception at the current time. Am I missing anything?


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## mdocod (Aug 13, 2008)

For comparisons sake, i just did some testing on another popular budget charger known as the DSD. I used a 5.7V 800mA Nokia cell phone adapter (12V car style) as the power source to get a feel for variations in behavior compared to the original 450mA adapter. Using the different adapter has actually helped reveal some things. 

I see no evidence of a CV stage in this charger either, and I think this charger ordinarily just takes advantage of it's normally very slow charging speed to top off cell without the need for a separate CV stage. 

I measured charging current right at ~810mA into a single 17670. In several tests the Charge always climbed steadily to around ~4.21-4.22V and then the charge terminated. The cells always settled to ~4.08-4.12V after termination. My gut tells me that with the charge current split between 2 cells, and using the original wall-wart adapter at 450mA... The termination at around 4.22V would semi-consistently result in larger size cells settling to ~4.18-4.20V, which is what I recall from years ago using this charger on a regular basis. (I have misplaced the original 450mA adapter, so I'm basing comparisons from memory of using this charger years ago).

So the DSD, is another example of a cheap charger with no apparent CV stage, that simply relies on characteristics of the cell to result in a charge that is semi-"acceptable." 

With slow charge rates, a CV stage is less important though, consider a situation where you have 2 18650 cells loaded into a charger that's splitting ~450mA between the 2. That's about a 0.1C charge rate, which is what a CV stage should terminate at anyways, this charger avoids the need for a CV stage by simply charging so slow that it's semi-irrelevant. On smaller cells, I would expect the charge termination to result in voltage settling even lower. 

Eric


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## Ray1968 (Aug 13, 2008)

Ray1968 said:


> Interesting. I'll try the same test tonight and post the results.


 
Ok, my reading got up to 4.31 when the light turned green. But unlike mdocod, my DMM didn't jump up to 10-11, it only jumped up to 4.62 and stayed there. Why the difference?

The cell had a reading of 4.14 right after charging.


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## mdocod (Aug 13, 2008)

Ray1968,

I explained why in the OP and again in post #7.

On AW RCR123s, the charge rate is fast enough that the charge voltage gets high enough to trip the PCB before the charge completes, this causes the circuit to go "open" and the volt-meter to read the full open circuit voltage of the charger. 

If you are using a different cell, be it a RCR123 with a different PCB style, or unprotected, or a larger protected cell, then the charge will terminate by the charger at around 4.31V.

The same thing that happened with your test is what happens when I run the same test with any of my 17500 or larger cells, and the larger capacity the cell, the lower the final charge-voltage is before termination. 

Eric


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## Ray1968 (Aug 13, 2008)

No, I meant the diffrence in this:



> The 11V reading is what you would get with no cell in place but with the charger plugged in.


 
You're getting 11v, I'm getting less than 5v.


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## mdocod (Aug 14, 2008)

Your PCB didn't trip, when the PCB trips, the charger goes open circuit and will read voltage the same as if there were no cell in place. 






me said:


> The ~11V reading is fine, it's the open circuit voltage of the charger and the cell is NOT seeing that voltage since the PCB has severed the circuit,





me said:


> On a pair of AW brand protected 17500s:
> Charge voltage was at 4.31V when the charger terminated the charge and voltage dropped to 4.22V still on the charger.


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## harddrive (Aug 14, 2008)

I wonder how the wolf eyes charger performs? It is priced between the Pila IBC and the cheap Ultrafire type models. Does anyone now if the wolf eyes functions like the cheap ones or more like the Pila?


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## mdocod (Aug 14, 2008)

I don't know much about the Wolf-Eyes 2-bay charger, but I do know that their "pack" chargers (tailcap and pack) use the cells PCB to terminate the charge and use a CC only charging style. 

However, since their cells and chargers are designed to work together, it's not much of a problem, the problem is when you try to take a charger that works best with a few cells, and try to use it for a wider variety of cells.


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## harddrive (Aug 14, 2008)

Thanks for the fast response. I think I better wait until I can afford the IBC.


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## lightforce2 (Aug 14, 2008)

mdocod said:


> Your PCB didn't trip, when the PCB trips, the charger goes open circuit and will read voltage the same as if there were no cell in place.


 
I've just set up a simulation of the PCB tripping however I'm getting the same results as Ray1968 is getting, the charger will jump from 4.28v (load) to 5.2v for a second then settle to 4.8v (open circuit) Cant get 10v or11v







My charger is terminating charge at 4.20 on battery, showing 4.28 on the DMM, the battery settles to 4.18v

Mdocod, your charger seems to be behaving differently to mine? Is your charger relativatly new? 
My feeling is the older WF-139's are the one's that are trickle charging? I cant get mine to trickle charge

cheers


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## mdocod (Aug 14, 2008)

Hello Lightforce2,
I think some of these discrepancies may prove that there were some design changes over the years. My WF-139 was ordered on 12-26-2006 from AW. 

Just to double check and clarify a few things here:

What voltage reading do you get when you just test the charger with nothing loaded? No PCB tripping simulation or nothing, no cell in place. Cause that's all that the 11V reading on mine is, it's the total and complete open circuit no-load reading of the charger. It happens to show up when a cells PCB trips in the charger, but there is no need to simulate a cells PCB tripping to find out whether or not this voltage is being reached by the charger in open circuit condition. 


Your charger, while different in some way, still appears to be using the same CC only charge algorithm, ramping the voltage up to ~4.28 on the larger cell is about what would be expected for that 18650 size cell... The larger the cell, the less voltage rise it will experience on it's way up, as it can absorb more of the charge (same charge mA rate appears "slower" to a larger cell)

Are you sure it's not the cell that's terminating the charge at 4.28V? I think that those tenergy 18650s have PCBs set to 4.25V (+/- some amount). 

Eric


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## ProofTech (Aug 14, 2008)

mdocod said:


> I don't know much about the Wolf-Eyes 2-bay charger, but I do know that their "pack" chargers (tailcap and pack) use the cells PCB to terminate the charge and use a CC only charging style.



The WE 2-bay chargers work in the same way as the pack chargers.


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## Ray1968 (Aug 14, 2008)

mdocod said:


> What voltage reading do you get when you just test the charger with nothing loaded? No PCB tripping simulation or nothing, no cell in place. Cause that's all that the 11V reading on mine is, it's the total and complete open circuit no-load reading of the charger


 
4.96v here. No load, no cell. Just plug in the charger and touch the test leads to the terminals. And when you do this you get 11v? This is the difference I was referring to earlier that I don't understand.


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## mdocod (Aug 14, 2008)

We have confirmation that there are definitely different versions of this charger out then.

So, with that in mind.

My WF-139, that reads ~11V open circuit, has a tendency to trickle charge cells after termination. 

Do the WF-139s that read ~5V open circuit have no tendency to trickle charge?

Perhaps a modern WF-139 that reads 5V open circuit could be given a higher "approval rating" if that's the case. 

I'm tempted to just replace this one with an IBC and just get it over with. lol. My problem is I love the fact that it has no wall wart and nice spring loaded slots, lol. 

Eric


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## Black Rose (Aug 14, 2008)

I guess the big issue then is how to tell (other than with a DMM) which version a person has.

mdocod, is your WF-139 modded to activate the RCR123 bays?


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## Exit32 (Aug 14, 2008)

I measured 4.85 open-circuit volts on my one-month-old WF-139. Tested both slots (empty) with DMM and got same result for both.


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## lightforce2 (Aug 14, 2008)

mdocod said:


> We have confirmation that there are definitely different versions of this charger out then.


 
Yes, I'm suspecting this too. My general observation has been that forum membes who have raised the 'trickle charge' issue seem to have older WF-139's



mdocod said:


> Do the WF-139s that read ~5V open circuit have no tendency to trickle charge?


 
This seems to be the case with mine



mdocod said:


> Your charger, while different in some way, still appears to be using the same CC only charge algorithm, ramping the voltage up to ~4.28 on the larger cell is about what would be expected for that 18650 size cell... The larger the cell, the less voltage rise it will experience on it's way up, as it can absorb more of the charge (same charge mA rate appears "slower" to a larger cell)


 
I wondered about that, thanks for confirming it



mdocod said:


> Are you sure it's not the cell that's terminating the charge at 4.28V? I think that those tenergy 18650s have PCBs set to 4.25V (+/- some amount).


 
I have a Tenergy cell with a hole in its plastic cover exposing the - terminal, so I'll bridge out its PCB & charge it to determine whether the charger or the PCB is terminating current. 
I'll also check the open voltage again and post results tonight

Cheers,


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## mdocod (Aug 14, 2008)

Sweet, looking forward to hearing the results. If Modern WF-139s are just using a CC stage, but do terminate without a trickle around 4.20V, then that wouldn't be to bad.

Eric


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## lctorana (Aug 14, 2008)

I definitely think that an open-circuit voltage of 11V is just plain wrong.

Whether or not the UF-139 turns out to be too harsh on batteries, yours is a dud.

(Mine gives 5.03 / 5.02 OC, btw)


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## jirik_cz (Aug 15, 2008)

Mine WF-139 has 5.00V open circuit voltage. 

I've tried the same test as mdocod, but with UNprotected cell.
Voltage during the end of charge was 4.24-4.25V, when the light goes green it goes immediately down to 4.14-4.15V and stays there. No change after many hours so no trickle charge.

I have also "Digital Li-Ion 18650 Battery Charger" with two bays from DX. Open circuit voltage is 4.18V. The light goes green when batteries reach 4.14V after that it trickle charges to 4.18V and stops completely there.


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## PhantomPhoton (Aug 15, 2008)

I have an older WF139 that I purchased from Lighthound in February of 2007.
Mine has an open circuit voltage of around 11.5V.

I tested my WE dual bay charger and it jumps around from 3.9-4.5V

Perhaps I'll take a look with the meter some time when I'm charging an 18650 in both of them.


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## FlashSpyJ (Aug 15, 2008)

My WF-139 was bought maybe a year ago. I read 11.42V and 11.44 with no load.

On the back of the charger it says that you should only charge 14500, 17500, 18500, 17670, 18650 batteries. I have charged my AW RCR123 a couple of times with no trouble so far...


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## Meterman (Aug 15, 2008)

I've never before used my WF-139 because of it's reputation at CPF.

To see what's going on with it, I have soldered an external batteryholder to the PCB to have solid access to voltage and current.

Idle voltage without a battery is 4.88xxV, decimal places 3 and 4 very bouncy. (Can you say so?)

The battery was not empty when connected; voltage started jumping between 4.03V and 4.04V. Red LED on, green LED flashing in 1.4s beat. Current was measured by means of a high precision DC current clamp to not influence the circuit. Current jumped between about 0.35A and 0.38A and every 1.4s a dip.

At the scope, using a different current clamp for scoping, the reason was to be seen: the Current to the battery is pulsating with a pause at no current every 1.4s.

The voltage went up and up, so eventually at no longer falling below 4.25V in the rhythm I removed the non-protected battery for reasons of safety.

Thus I could not check for trickle charge.

I'd love to show the graph of the scope, but I don't find a way for attaching it.

Wulf

Edit: Thank you, _Mr Happy_, seems to work!
PDFs are better, but can't be uploaded this way. I'll see, what I can do.





[/URL][/IMG]

There is *current* shown, 100mV/A.


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## Mr Happy (Aug 15, 2008)

To attach images to posts, upload them to a free hosting site like ImageShack and then include the image in the post with the image tool on the toolbar (the image tool is the icon that looks like mountains with the sun above them).


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## Chongker (Aug 15, 2008)

Just tested this myself. On my first WF-139 (I have two ), with two RCR123 cells in the charger, I get a charging voltage of 4.30 - 4.35 V, but with only one cell in it, it sometimes jumps up to 4.4V!  Is this particularly safe? And if not dangerous, how much is it damaging the poor little cell? Don't want it to eat away too many charging cycles  Gonna test it soon with a larger cell soon.

Ohh, and btw, open circuit both my chargers read ~5V. Both were purchased this year (quite a newb here). Seems like the revision Ultrafire did was sometime in the past 1-2 years or so?


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## OceanView (Aug 15, 2008)

Hmmm, very interesting story unfolding in this thread.

I just checked my WF-139 ordered in January 2007. No load is ~11V here, too.


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## mighty82 (Aug 15, 2008)

I'm testing my trustfire TR-001 right now. It looks similar to the WF-139 but it's a few dollars cheaper. The open circuit voltage is actually 0.0V. I guess this is a good thing? I'm charging a 14500 battery with a voltmeter attached so I can see if it terminates better than the WF-139. In that case it might be a better alternative  Have any one else tried this charger?


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## lightforce2 (Aug 15, 2008)

mdocod said:


> Sweet, looking forward to hearing the results.
> 
> Eric


 
I bridged out the PCB on the Tenergy 18650 (to isolate PCB) & charged - The charge voltage peaked at 4.28v, the cell voltage was 4.20v at termination, the cell then settled to 4.18v. This is the same charging rate that I always see with protected Tenergy's

Interestingly I charged some AW 18650's that came in the post yesterday - Charge voltage peaked at 4.25v, the cell was 4.18 upon termination and then settled to 4.16. In this case it would appear the cells PCB may have terminated the charge otherwise the WF-139 would have taken it a little higher??

There's some very interesting test results showing up with the new vs older WF-139's!!

cheers


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## jenskh (Aug 16, 2008)

My 139 shows a voltage that is constantly fluctuating between 4,95 and 4,75 when no battery. The charget also fluctuates with about 0,2 V while charging. 18650 batteries normally comes ot of the charger with 4,21 V a little while after the charger has turned green. I am also using it for 10440 batteries (I know I shouldn't). They comes out of the charger with 4,1 V.


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## TigerhawkT3 (Aug 16, 2008)

My WF-139, bought in December '06, shows about 11.6V OC. My universal NiMH/Li-Ion travel charger from KD shows 9.6V OC. My Nano charger (for AAAs) shows 4.29V OC. None of them have burned down my house yet, but I'd like to keep it that way. I'm guessing that using protected cells (except for sizes like 10440, which don't have a protected version) is the solution, right?


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## zipplet (Aug 16, 2008)

I'd rather use the nano than the WF-139 if I were concerned about safety. Using protected cells works but the way the WF-139 terminates is going to shorten cell life compared to a proper charger such as the pila IBC.


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## RangerJ (Aug 19, 2008)

OK, so we have established that the older WF-139's are no good. But, what about the newer ones. I have a brand new WF-139 with some new AW 18650's. The charger's voltage with no battery is 4.90V. Is this charger going to be OK? Perhaps I need to check the voltage while its charging to see if mine goes over 4.20V. How much over 4.20V can my batteries handle? Maybe I just need to get the Pila charger :thinking:


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## lightforce2 (Aug 19, 2008)

RangerJ said:


> The charger's voltage with no battery is 4.90V. Is this charger going to be OK? Perhaps I need to check the voltage while its charging to see if mine goes over 4.20V. How much over 4.20V can my batteries handle? Maybe I just need to get the Pila charger :thinking:


 
For the battery to charge, current must flow into it. For this to happen the voltage at the charger needs to be higher than the voltage at the battery. 
Exactly how much higher should the input voltagebe ? I'm not sure about that, a question that mdocod or silverfox may have the answer for

cheers


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## zipplet (Aug 19, 2008)

It doesn't have to be higher than the max topping off voltage. A simple li-ion charger can supply 4.2V limited continuously with current limiting (a so called CC/CV charge).

CC = constant current - the battery absorbs energy at a maximum limited current until it hits the top off voltage.
CV = constant voltage - the battery is at the top off voltage (4.2V for normal li-ion), but is still charging (current is dropping)


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## lightforce2 (Aug 19, 2008)

zipplet said:


> It doesn't have to be higher than the max topping off voltage. A simple li-ion charger can supply 4.2V limited continuously with current limiting (a so called CC/CV charge).


 
If the charger had a maximum output of 4.2 then the charging would be self limiting once the battery voltage was raised to 4.2, in effect the charger & the battery would equalise??


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## zipplet (Aug 19, 2008)

Correct that is what happens however it is good practice (and manufacturers insist) to terminate charging once current drops below a certain level (I'm using 0.1C) otherwise you keep the cell at that voltage for a prolonged time which causes degredation.


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## harddrive (Aug 20, 2008)

OceanView said:


> I just checked my WF-139 ordered in January 2007. No load is ~11V here, too.




Mine is about that age too and reads about 11.6V.


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## lctorana (Aug 20, 2008)

lightforce said:


> If the charger had a maximum output of 4.2 then the charging would be self limiting once the battery voltage was raised to 4.2, in effect the charger & the battery would equalise??


Yes. That is right.

However, during the earlier, "CC" stage, it is perfectly acceptable for a much higher source/supply voltage to be used *via a current regulator*. Then, when the battery reaches a certain voltage (_SilverFox, please tell us what that knee voltage should be_), the source voltage shoud be rigidly clamped at 4.2V (or 4.19 or whatever) for the "CV" phase.


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## Mr Happy (Aug 20, 2008)

lctorana said:


> Yes. That is right.
> 
> However, during the earlier, "CC" stage, it is perfectly acceptable for a much higher source/supply voltage to be used *via a current regulator*. Then, when the battery reaches a certain voltage (_SilverFox, please tell us what that knee voltage should be_), the source voltage shoud be rigidly clamped at 4.2V (or 4.19 or whatever) for the "CV" phase.


Actually, that voltage would be 4.2 V (say).

What happens is that if you applied 4.2 V to a discharged battery, the current would be higher than the maximum permitted. The current regulator in the circuit works by reducing the voltage below 4.2 V and thus reducing the current to the designed limit.

As the cell charges, the cell voltage rises towards 4.2 V, where it stops and should go no higher. Meanwhile the cell continues to charge and the current limiter has less and less work to do. Eventually, the current limiting drops out of circuit and the current slowly falls towards zero.

When the current reaches a preset minimum value the charger should switch off.

Not all real chargers (e.g. the WF-139) may follow exactly that algorithm, but that is theoretically how Li-ion chargers are supposed to work. The voltage should not be allowed higher than 4.2 V because that may cause chemical damage that will reduce the life of the cell, and the current should not be allowed higher than the permitted maximum because that may be too much for the cell to absorb and may also cause damage.


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## Norm (Aug 20, 2008)

My WF-139 is an older one measures 11.8V.
Fortunately I no longer use it, I do all my charging with http://www.hobbycity.com/hobbycity/...me=iCharger_iC6_Digital_Balance_Charger_6cell
and a VoltCraft battery holder https://www.candlepowerforums.com/posts/2471925&postcount=56
Interesting thread, just wondering what people think of the older Wolf-Eyes Charger CH-02 it seems to depend on the battery's protection circuit to terminate the charge, I once put an unprotected 18650 in it and the voltage was way over 4.2V (can't remember exactly how high).
Norm


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## EssLight (Aug 20, 2008)

Just to add my own data to the mix, I have a WF-139 that I bought from Lighthound in August 2007. When charging AW protected 18500s, the protection circuit on the cells would reliably terminate charge at 4.25 V, at which point the charger would then show 4.60 V across the open protection circuit. I got in the habit of monitoring the charge and manually stopping it when the cells were around 4.15-4.20 V. With no battery in the charge bay, the voltage across the charger terminals is 4.90 V. 

I feel reasonably confident using my WF-139 to charge protected cells, as long as I keep an eye on it. I'm curious at what voltage my charger would terminate with an unprotected cell, but I don't have sufficent fire protective gear to run that test. 

EssLight


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## mdocod (Aug 20, 2008)

The only unprotected cells I own are some Emoli 18650s obtained recently. Since this is a much safer chemistry I wasn't afraid to leave em on the charger and see what would happen, I didn't monitor them to see how high the charge voltage got up to during the charge, but the cells were sitting at 4.18V when the light turned green, not too bad I suppose. 

For now I'll continue using this charger and mostly just avoid letting it sit and trickle after it turns green, as that is really the biggest problem with the charger. The CC only charge style that ramps up to ~4.30V during the charge is really not as awful as it sounds, it's not *good* but it in and of itself is very unlikely to cause an explosion or anything, especially on a protected cell that can terminate the charge if it gets way out of hand. As mentioned previously, the Wolf-Eyes system has been using this charging method for a long time, and I have not heard ANY reports on these forums of a wolf-eyes cell exploding.


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## matrixshaman (Aug 20, 2008)

I haven't read the whole message thread here so I apologize if this has been covered - but my WF-139 reads only 5.02 volts open circuit - no batteries in it. I usually pull batteries off it shortly after the light goes green but have sometimes missed getting them off by a half hour or so and I still normally have only 4.2 volts or less on any batteries I pull out - I almost always check the voltage when I pull one out. Is it possible your charger is defective or is an early one that didn't have the best circuit? Has anyone else checked the voltage on it? 
And to answer my own question again now that I've read more I see most of this has been covered


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## AW (Aug 20, 2008)

My cell phone charger ( Nokia ) measures 6.02V open voltage and I have been using it everyday for the past few years without killing my LiIon phone battery. Please check and see you mobile devices chargers and see what their open voltage is. Most will list an output voltage of 5.5V but measures higher.


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## matrixshaman (Aug 20, 2008)

Yes -- most chargers do have a higher voltage and some by quite a lot more than the battery they charge. I designed chargers a couple times using an engineering book on them and having a voltage a lot higher than the battery is not so much of a problem as having too much current or no shutoff timer or detection point for shutoff. It looks like some of the old ones were a little less accurate in their cutoff point but the one I have seems okay so far.


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## mdocod (Aug 21, 2008)

Matrix, you have one of the newer units with what appears to be a lower open circuit voltage and better charge termination. Within this thread we have revealed that it's the older WF-139s that have the higher open circuit voltage and a tendency to trickle charge cells. But all of the WF-139s lack a true CV stage with 4.20V cap while charging.


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## zipplet (Aug 21, 2008)

Cell phone chargers in my experience are simple dumb power supplies and the charging circuitry is actually *in the phone*!

Charge control ICs such as some microchip parts are used.


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## SilverFox (Aug 21, 2008)

Hello Zipplet,

Actually, the power supply can act as a current regulator.

Here is a discussion on one version of cell phone charging chip.

Tom


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## zipplet (Aug 21, 2008)

Interesting link SilverFox. That explains why cell phone manufacturers are insistant on you only using the supplied charger... one capable of too much current with a phone using the last method discussed at that URL would charge the li-ion/poly too quickly - *bang!*

I always thought all of the charging circuitry was inside the handset (including current limiter) and that any PSU of the correct voltage would do the job.


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## mitch79 (Aug 23, 2008)

I just got a WF-139 and a pair of Trustfire 14500's from DX today.
Mine terminates the charge at 4.16V and I do believe it does terminate the charge completely, with no trickle.

A few hours ago I wired up the two RCR-123 charging bays, a side effect is it allows easy voltage monitoring with a DMM.

With a single 14500 in the charger I measured the voltage after the lights had turned green with it still plugged in and turned on.
The empty bay reads 4.910V, the bay with the 14500 reads 4.166V.

So if my WF-139 is holding 4.166V after termination I can't see it doing any damage to the cells if I accidentally leave it on for an extended period of time.

EDIT: I'll leave the battery in the charger for a few more hours and monitor the voltage.
EDIT 2: Well 2 hours later and it's still holding the same voltage. Looks good.


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## mdocod (Aug 24, 2008)

mitch79, 

if the cells are terminating at 4.16V, then it's probably ramping the voltage up during charging like mine to about 4.35V, at which point the cell is terminating the charge (protection) before the cell can absorb enough to hold close to 4.20V after termination.

Eric


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## TigerhawkT3 (Aug 26, 2008)

I just got a camera battery charger (charges one LiPo at a time, out of the camera), and I checked the voltage after it finished charging, thanks to this thread. 

The charged cell was 4.26V, and the charger was 4.26V OC without any cell in it. I'm pretty sure the cells are unprotected, but they're LiPos, not ordinary Li-Ions (I don't feel like looking up the exact chemistries; you know what I'm talking about). Is this a safe charger, or should I return it?


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## Mr Happy (Aug 26, 2008)

Sources vary slightly on the exact numbers, but the maximum charging voltage for lithium polymer batteries is variously given in the range of 4.25 to 4.3 V per cell, so your charger seems right on spec. Any voltage above 4.3 V would be a big danger sign though.


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## TigerhawkT3 (Aug 26, 2008)

Mr Happy said:


> Sources vary slightly on the exact numbers, but the maximum charging voltage for lithium polymer batteries is variously given in the range of 4.25 to 4.3 V per cell, so your charger seems right on spec. Any voltage above 4.3 V would be a big danger sign though.


:sweat: Thanks.


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## chewy78 (Nov 7, 2008)

what do you guys think about the tr-001 charger?


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## chewy78 (Nov 7, 2008)

[/quote]As mentioned previously, the Wolf-Eyes system has been using this charging method for a long time, and I have not heard ANY reports on these forums of a wolf-eyes cell exploding.[/quote] 

thats somewhat good to hear for i ordered a we m90 with that charger, maybe i will try a tr-001 charger and see what the voltage terminates at.


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## LiteTheWay (Nov 11, 2008)

I checked my WF-139 bought from DX in March 2008. With circuit open and no cells in it, it reads 4.93v left channel and 4.94v right channel.

So I guess this is consistent with other findings here that the 'recent' versions are different.

I never leave cells in the charger unattended or after the light goes green even so and don't plan to. And I'm getting a Pila IBC anyway.


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## mdocod (Nov 11, 2008)

Sounds good, that's for the update. 





7histology said:


> I checked my WF-139 bought from DX in March 2008. With circuit open and no cells in it, it reads 4.93v left channel and 4.94v right channel.
> 
> So I guess this is consistent with other findings here that the 'recent' versions are different.
> 
> I never leave cells in the charger unattended or after the light goes green even so and don't plan to. And I'm getting a Pila IBC anyway.


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## StandardBattery (Nov 11, 2008)

Great Thread! Since the 18650 batteries last so long I hardly need to use my chargers. After reading the thread though I just had to measure the open circuit voltage of my UltraFire WF-139, and like anothers here, *open circuit voltages are 4.93V and 4.94V*. The charger is from the most excellent Lighthound, ordered on *Sept. 15, 2007*. 

Because of all the stuff in the past about these chargers I had measured the cells off my charger in the past and they were always fine, can't remember the numbers. Still to play it safe I bought a Pila when one of those good deals came around. However, the cells last so long that I have not needed to charge them much, and I have not even used the Pila. The 139 was just too convient, all set up and waiting. I'll be connecting the Pila up soon when my next 18650 based light arrives. I've not had any problems with the WF-139. I only use AW protected cells in it.

I will have to use my rechargable lights more, and let the primaries sit. They are often small single cell lights though so they get more use.


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## effulgentOne (Nov 12, 2008)

I'll just add my own observations, which are consistent with those made by others:

- My WF-139 has an open circuit voltage around 11V (bought early 2007)
- It charges my (protected) 18650's to about 4.20V
- It charges my (also protected) AW RCR123 cells to about 4.10V or a little less

These numbers are from memory, as I don't use 18650's much anymore, and I use a WF-138 most of the time for my RCR123s.


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## Stromberg (Nov 16, 2008)

Does anyone know what version is currently been sold at 4Sevens? Meaning this AW-139

https://www.4sevens.com/product_info.php?cPath=53&products_id=207

?

And what seems to be the conclusion about using AW-139 with protected 14500 and 18650, is it recommended or not?


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## mdocod (Nov 16, 2008)

Yea, I suppose a conclusion is not a bad idea: 


*All WF-139 chargers, regardless of what "version" it is. Use a Constant Current only charging algorithm that can reach *charging* voltages of ~4.25-4.35+V during charging depending on the capacity of the cell being charged. *
Charging a small unprotected cell in with this type of charger could cause charging voltages of 4.4V or higher to be reached in theory.
Most would agree that this charging method does not follow most li-ion manufactures recommendations for charging, and will probably reduce the life of the cell.
Charging a small unprotected cell (like a RCR123) in this charger, could come with increased risk of fire/explosion. 

The Older WF-139 chargers, will measure ~10-12V open circuit, and will continue to trickle charge cells after the charge has been terminated. This could lead to fire/explosion if left unattended for long periods of time.
If the charge is terminated by the cells protection, which is very common when protected RCR123 or similar size cells are charged in this charger, the cell will not be trickle charged because the cells protection will hold the circuit closed after it has tripped.

Newer WF-139 chargers, will measure ~5V open circuit, and will not trickle charge after termination.

With all of that in mind, I would say it's a personal choice whether or not to use this charger, I am using mine less and less in favor of a DSD with a Nokia power supply. The DSD is much more well behaved and you can buy 2 or 3 DSDs for the price of a WF-139 if you know where to look. I will continue to recommend the Pila IBC with absolute confidence. 

Eric


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## csshih (Nov 17, 2008)

I wish I could afford a decent charger, and not this.


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## jumpstat (Nov 17, 2008)

This is lights what I have that runs on AW's rechargeables...
PD-S - $325
Mule Ti PD - $425
M6 - $300
MN Socket/Battery Holder - $90
SF E1L - $85
3xP17670, 6xP18650, 10xR123a - $150
--------------------------------
Total $1375 total investment......
--------------------------------
10% of the above ($137) for a decent charger I think is a good idea? Compared to the UF WF-139 at $18.50 shipped.....

Anyway, I have yet to invest in a good charger as the WF-139 I currently have have not had any issues whatsoever. It registers a 4.93v at no load.


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## hank (Dec 6, 2008)

> DSD with a Nokia power supply ... if you know where to look

I found a thread about problems with the stock DSD that mentions looking for Nokia power supplies to use with them. But I'm not sure I know where to look; any summary/pointer?


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## mdocod (Dec 6, 2008)

hank said:


> > DSD with a Nokia power supply ... if you know where to look
> 
> I found a thread about problems with the stock DSD that mentions looking for Nokia power supplies to use with them. But I'm not sure I know where to look; any summary/pointer?



You can find DSD chargers on the "bargain" retailers around the net for about $5. 

Just use the included power supply until it gives up the ghost or you loose it, then pick up a Nokia power supply with the same plug style. They can be found at walmart and target and stuff for pretty cheap, or probably even cheaper online- but the quality of the chargers from off-brands around the net may be sort of hit or miss.


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## hank (Dec 8, 2008)

I got a Nokia charger in the junkbin already!

One more on the DSD, I saw this:
http://candlepowerforums.com/vb/showpost.php?p=1585419&postcount=37
Is that all still an issue?


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## mdocod (Dec 9, 2008)

hank said:


> I got a Nokia charger in the junkbin already!
> 
> One more on the DSD, I saw this:
> http://candlepowerforums.com/vb/showpost.php?p=1585419&postcount=37
> Is that all still an issue?



I have no reason to assume that any design changes have been made to the original power supply, thank you for pointing that out. 

Nokia power supply sounds like the best bet for use with these DSDs to get a reasonable li-ion charger put together for a reasonable price. 

Eric


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## Stromberg (Dec 10, 2008)

My 139 arrived from 7777 with 14500 and 18650. It seems to be new model with ~5V open circuit. Sadly the charge voltage peaks as high as 4.36V but at least it's not constant charge voltage. I think that I'll monitor the voltage and remove battery when it reaches 4.25V.


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## jabe1 (Dec 10, 2008)

Mine was purchased last march and is showing a no-load of 4.89v.
Still, I think I'll start saving for a Pilla...My home is worth it!


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## Search (Mar 30, 2009)

I resurrected this instead of opening a new thread.

Recently decided to try 18650 on my TK11 R2 being as people seem to think it has better regulation than the Q5 version.

I'm going with AW 18650's but can't decide between the 139 or IBC.

I don't mind searching for the IBC and paying the extra if the general consensus is the 139 is just unsafe.

After reading every post in this thread it's still unsure where people stand on safety. I value my home and everything in it, so I don't want crap blowing up.

When my TK11 started showing signs on dimming I would swap batteries (as I plan on buying two) and then recharging the dimmed battery that night

It would go in the charger when I got home and depending on how fast it charges (as I don't know) I would either pull it out when the green light came on before I went to sleep or after I woke up.

Under these circumstances, would it be safe to go ahead and get the 139 with my 18650s or just go ahead and locate an IBC?


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## mdocod (Mar 30, 2009)

Hello Search,

If you are wiling to pay the extra for an IBC then that is absolutely my recommendation. I'd rather have 1 IBC than 3 139s any day. 

http://www.flashlightz.com/product.php?p=pila_bc01-ac01&product=171829
http://www.bugoutgearusa.com/bach.html

Flashlihtz.com used to carry it on sale for $34, that was a steal and I'm still kicking myself for not picking one up at that price. 

If the $45-50 price is hard to justify, or you find it difficult to get an IBC (not in USA etc), then I would personally opt for a DSD instead of a 139, that is, IF you live in a place with 110V, not 220V, or can also immediately swap it to a 220V compatible wall-wort that works more reliably there. The DSD can later be upgraded to charge about twice as fast with an 800mA cell phone charger power supply. I found a perfectly good one during a phone drive we were running at work. The 800mA charging rate is a blessing for cranking through individual cells, sine the DSD has both channels wired in parallel, the full 800mA will be used to charge a single cell if only one cell is installed. Which is perfect for users who intend to be charging primarily just 1 cell at a time. With the 800mA power supply, the DSD will actually charge a single 18650 faster than an IBC will, however, an IBC will charge 2 18650s faster than the DSD would.

Just keep in mind that the DSD will wire any 2 cells you install into it in parallel, so they need to be in a similar state of charge so one does not drain off into the other rapidly, exceeding the maximum recommended charge rate of one of the cells. 

Also: Review Post #80 in this thread. 

-Eric


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## Search (Mar 30, 2009)

mdocod said:


> Hello Search,
> 
> If you are wiling to pay the extra for an IBC then that is absolutely my recommendation. I'd rather have 1 IBC than 3 139s any day.
> 
> ...



With that said I'll just go ahead and get the IBC.

I want something that I can pop the battery in and then not have to worry about getting it off the charger as soon as it's done and don't have to worry about it exploding.

While the DSD does sound nice, I would rather go with you get what you pay for.

While your post confused me more than it helped me, I'll take your word that it's still unsafe and could cause the batteries life to be reduced.

With this in mind, I'm going to go ahead and order the IBC for two reasons (the most important reasons):

1) Safe
2) Simple (I just want to pop it in and know it's always going to work right)

Thanks for the help.


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## cernobila (Mar 30, 2009)

Perhaps we could look at this issue in this way.....

Do you drive a car?
Do you drink or smoke
Do you have gas and electricity in your house
Do you have unprotected sex
Would you fly in a plane
Do you operate machinery when sick and on medication or after very little sleep
Do you have a swimming pool at home
etc. etc.

Statistics show that adults and children die or are seriously injured due to human error every day in large numbers.......just by doing everyday things we all take for granted and don’t think about very much.

I would suggest that if the WF-139, Pila and WE Li-Ion chargers are used according to the basic instructions that are supplied, than you would be safer than taking part in most of the everyday activities above.

btw, my latest WF-139 charger (I give mine away with lights as gifts) is more consistent than my Pila IBC chargers, the AW 18650 cells come of reading either 4.19 or 4.20.....the cells that come of my two Pila IBC chargers range between 4.15 and 4.19.


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## Search (Mar 31, 2009)

cernobila said:


> Perhaps we could look at this issue in this way.....
> 
> Do you drive a car? *Truck*
> Do you drink or smoke? *No and No (Dip)*
> ...



I guess I have to think more.


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## mdocod (Mar 31, 2009)

cernobila said:


> btw, my latest WF-139 charger (I give mine away with lights as gifts) is more consistent than my Pila IBC chargers, the AW 18650 cells come of reading either 4.19 or 4.20.....the cells that come of my two Pila IBC chargers range between 4.15 and 4.19.



The point being made here, over an over again, in this thread, and what sparked me to start this thread, is that, the WF-139 achieves charging voltages that are higher than ideal. Higher than li-ion cell manufactures have specified as being safe for the cells. This thread has very little to do with resting voltages after termination, which is only an issue for the older generation of wf-139s, that have trickle charging problems. 


Another analogy:
Would you put a non-detergent motor oil in your modern vehicle that calls for a modern oil formulation with detergents?

-----

Out of curiosity, are there any differences in age of those AW cells that come off your Pila chargers at different voltages?


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## mdocod (Mar 31, 2009)

This thread over yonder was just bumped and I had forgotten all about it, worth a look for sure, it points out a WF-139 behaving badly when a cell that has already been charged is re-inserted...

https://www.candlepowerforums.com/threads/209785

Also, Thanks to rantanplan, I think my new favorite charger recommendation for folks on the cheap will be the DX 6105, that charging graph is perfect.


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## Black Rose (Mar 31, 2009)

Sigh...and I bought a WF-139 from 4Sevens last week for my AW, TrustFire, and Solarforce protected cells.

I'll test it with a DMM once it gets here and see how it acts.


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## cernobila (Mar 31, 2009)

mdocod said:


> Another analogy:
> Would you put a non-detergent motor oil in your modern vehicle that calls for a modern oil formulation with detergents?
> 
> Out of curiosity, are there any differences in age of those AW cells that come off your Pila chargers at different voltages?



I am no expert on electronics nor do I have the equipment to do the kind of tests that are referred to here. I was under the impression that the protected cells have a cut of point during charging to protect them from overcharging. When I use any charger I look at the physical condition of the cells, the reading before it goes in and once the green light comes on I take the cells out and make another reading. In this regard I see little difference between all the chargers that I have been using other than the general "end-reading" pattern that is easy to follow.

I rely on people that have the knowledge and ability to dissect, analyse and provide facts for the rest of us to take on board. This is why I am on here, to learn.

...The cells I use are all AW and are mostly of the same batch, because I have many of them and they are rotated, they do not see much actual use. 

One more point that is repeated often, the consistency of these products is not very good in some cases. One person will quote that their charger "A" works perfectly while his friend who bought the same "A" charger finds that his is overcharging to unhappy levels....Perhaps when doing tests, more than one unit of the model should be used.


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## mdocod (Mar 31, 2009)

unfortunately, the protection circuits on li-ion cells are often setup to trip at a much higher voltage than would be ideal. There are several reasons for this, but the main one I can think of is as follows:

Take the Wolf-Eyes chargers, and the OLD pila (pre IBC) chargers for example. The way they worked, was to charge at a good fast rate, and quickly reach the cells PCB trip point for over-voltage. The PCB would trip and terminate the charge. The resulting resting voltage after charge was sort of a coincidence (by design) and happened to work out to ~4.20V or less. If the PCB on the cells was set lower (to say, 4.25V, which would be more ideal for most other chargers IMO), then they would never be fully charged when used with wolf-eyes and older Pila chargers. Again, I'm not a big fan of this charging method, but because the method is used in the industry, PCB design for this type of cell setup sort of standardized on maintaining that compatibility, (so far as I can tell).

The problem I see, is that, in the long run, the WF-139 is going to cause more wear and tear on the cells than ideal, in the end, this will usually just translate to replacing cells more often, worst case scenario, it could translate to making a cell chemically unstable, increasing the chances of an incident. There are cheaper chargers that are easier on the cells, so I don't have any way to justify a purchase of a WF-139.


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## cernobila (Mar 31, 2009)

mdocod said:


> The problem I see, is that, in the long run, the WF-139 is going to cause more wear and tear on the cells than ideal, in the end, this will usually just translate to replacing cells more often, worst case scenario, it could translate to making a cell chemically unstable, increasing the chances of an incident. There are cheaper chargers that are easier on the cells, so I don't have any way to justify a purchase of a WF-139.



So there is no real emergency to change chargers other than to improve the longevity of the AW cells. You have mentioned the DX 6105 in one of your posts as the charger you would pick to replace the WF-139. I am thinking of replacing all my friends chargers from the WF to something basic and reliable, none of these people are into flashlights and just want a charger to charge their AW 18500/18650 cells and don't care for the details. Is the DX 6105 still your suggestion in this case?

.....ps. can the DX 6105 charge two cells at different starting voltage?


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## jirik_cz (Mar 31, 2009)

6105 charger is not much better. some pieces overcharges to more than 4,25V... I have wf-139 and pila ibc charger and both work well.


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## cernobila (Mar 31, 2009)

jirik_cz said:


> 6105 charger is not much better. some pieces overcharges to more than 4,25V... I have wf-139 and pila ibc charger and both work well.



This is what I have found from practical experience with these chargers, but as shown here in the many technical discussions we do not know what happens "under the skin" so to speak while we are watching TV or doing something else, we do not know what happens during the charging process........and this is what I am interested in. I think the key issue that comes out of all this is that no two units of the same model are exactly the same in performance. Some say that a "unit" is great while others say that the same model overcharges. Perhaps there are no cheap chargers that please all that have them and the only answer is to be prepared to spend more than you expected, perhaps the Pila IBC is one of the few that comes close.

On a side note, perhaps we could contract a company to make "CPF" chargers, smaller model with the specifications that suit charging all Li-Ion cells up to 18650 size and a larger model with specifications that suit charging the bigger protected C and D cells such as the AW C and Kai D.......its ok, I will keep on dreaming.......


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## mdocod (Apr 1, 2009)

cernobila said:


> So there is no real emergency to change chargers other than to improve the longevity of the AW cells.



With quality cells like AWs, there is very little increased danger using the WF-139, as they have a good track record of safety and were designed to be used as replacements in application with these less than ideal charging methods used, however, prolonged use of any brand of cell in such a charger will increase the risk of an explosion. My biggest fear is the use of lesser quality cells in one of these chargers, the combination of an "on-the-edge-of-safety" cell and a wf-139 probably compounds the likelihood of an explosion, to what degree I can not say. I can only make recommendations based on what information I have gathered and will never be able to predict the future for everyones situation, though, this is of course, where everyone ultimately wants me to go with this. 



> You have mentioned the DX 6105 in one of your posts as the charger you would pick to replace the WF-139. I am thinking of replacing all my friends chargers from the WF to something basic and reliable, none of these people are into flashlights and just want a charger to charge their AW 18500/18650 cells and don't care for the details. Is the DX 6105 still your suggestion in this case?
> 
> .....ps. can the DX 6105 charge two cells at different starting voltage?



I'm leaning towards the 6105 based on looking at that charging graph I linked to previously. If they all have that graph, then that's a much better charger, if they are prone to problems and overcharging also, then I don't have a one-size-fits-all budget recommendation at this time, they all have their tradeoffs and each person will just have to decide what they are willing to give on to get what they want out of a charger.

-Eric


----------



## callmaster (May 6, 2009)

I just bought 3 x WF-139. Shoot!


----------



## Font size (Mar 29, 2010)

*Re: Running tests on the WF-139. Interesting results.*

*[FONT=&quot]


moldyoldy said:



I wonder about the presumed cell damage under conditions of a constant current charge cycle raising the cell voltage above the desired 4.2v when in fact the cell chemistry is still below a nominal fully charged state. Is the cell damage incurred by overcharging the chemistry beyond a full charge? 

Or does is the cell damage incurred at any time when the cell is above 4.2volts regardless of the status of the cell chemistry??

Click to expand...


When does the proposed cell damage occur?***[/FONT]


----------



## mdocod (Mar 30, 2010)

*Re: Running tests on the WF-139. Interesting results.*



Font size said:


> *[FONT=&quot]
> 
> When does the proposed cell damage occur?***[/FONT]




Li-Ion cells are in a constant state of degradation from the day they are manufactured. The state of charge and storage temperature greatly effect the longevity of the cells. There is no specific point in time when all of the sudden damage starts to occur, the cells are always aging. Modern cells stored or operating in the 3.7V-4.1V range under conservative loads are very likely to last over a thousand cycles and may very well last as long as 7-10 years or better. I would estimate that the same cell subjected to constant charge voltages above 4.25V in conjunction with other typical abuses (like discharges below ~3.5V, or 3.0V, perhaps discharge rates in excess of 1C thrown in for fun), would have a cycle life of anywhere from 100-400 cycles and a useful life-span of 3-5 years instead of 7-10. 

These are just estimates. You can choose to use your li-ion cells however you see fit but I suggest treating them well and they will treat you well. In the larger picture, if cells are used heavily, the cost of replacing them every few years even if they weren't taken care of is still much lower than buying primaries so in the long run it may not be a big deal to some people. 

Signs of a deteriorated and un-safe cell: 
Won't hold above 4.0V after resting for a day or 2 off a fresh charge. Capacity dropping below 80% of original. More heating during charging, charging taking longer in conjunction with more heat than before. Etc Etc. 

Eric


----------



## Tuikku (Apr 7, 2010)

This might be a tricky question but...:

I have ordered WF-139 for my RCR123 & 10440 batteries.
I was not aware of this kind of problem BUT I don´t trust so much on these chinese chargers, that I would leave batteries to charge without surveillance anyway.


Point: 
I didn´t know about this problem BUT I heard from my friend about problems, when using it with 230VAC. Naturally, this problem doesn´t affect most of CPF users, since you have 110VAC.

These chargers tend to burn their circuits when used in 230VAC. My friend said what was wrong but since I´m non-pro in electrics... :shakehead
It was something related to transforming 230VAC -> DC.
He has had two failures. One burned WF-139 and one sku.1236







BUT:
WF-139 has a secondary power input behind it.
I bought an universal powersource to plug in 230VAC and feed WF-139 with DC.
When doing so, it works.


My question is:

Does the problem described in this thread occur also, when I´m using secondary AC->DC converter instead of WF-139´s own one


----------



## mdocod (Apr 7, 2010)

Hello Tuikku,

The charging algorithm of most li-ion chargers will remain about the same regardless of whether you use the 12V DC input or the 100-240V mains input. I have not tested this specifically but have no evidence to prove otherwise. 

The results I posted in this thread, are related specifically to the first generation WF-139. Since then, there have been at least 2 more revisions of this charger and each is slightly different. 

As I understand, the 2 most recent versions, are not going to trickle charge, but at least one of them poses the risk of missing termination all-together under certain circumstances. All of them use a CC only or modified CC only charge method that will result in charge voltages (not cell voltages) in excess of 4.25V for most cell types and sizes. 

Eric


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## HKJ (Apr 7, 2010)

Tuikku said:


> Point:
> I didn´t know about this problem BUT I heard from my friend about problems, when using it with 230VAC. Naturally, this problem doesn´t affect most of CPF users, since you have 110VAC.
> 
> These chargers tend to burn their circuits when used in 230VAC. My friend said what was wrong but since I´m non-pro in electrics... :shakehead
> ...



I have been using a couple of WF139 on 230VAC for some time now, without any problems.


----------



## Font size (Apr 7, 2010)

*Re: Running tests on the WF-139*




Tuikku said:


> I have ordered WF-139 for my RCR123 & 10440 batteries.


 *From what I read here the 123 are not supposed to be used on the WF-139 charger. 


moldyoldy said:



Using the charger specifications for the WF-139 charger as an example: Battery to be charged: "18650, 17670, 18500, 14500, 17650, 17500". Battery type identified is "Li-Ion.” That is all. The WF-139 charger specifications do not identify an RCR123a or an IMR 16340 cell.

The WF-139 is commonly sold with spacers to charge lower capacity cells such as the IMR16340 or RCR123 cell in a charger slot intended for a maximum of the 18650 size. This usage practice is NOT per specification of the charger. 

A low capacity cell such as the RCR123a, which was NOT identified in the charger specifications, often demonstrates an overvoltage while under charge (exceeding 4.2x volts). Since the constant current charging method briefly stops charging to measure the cell voltage,

.. can be just as "bad" as the WF-139, which was not designed for the RCR123a Li-Ion cell.

Click to expand...

* *[FONT=&quot]A low capacity cell, which was NOT identified in the charger specifications, often demonstrates an overvoltage while under charge.***[/FONT]


----------



## liveforphysics (Apr 7, 2010)

Only the SOC voltage has any bearing on the potential damage to the cell, or danger of cell failure. 

When we do 5C continuous charging, or 10-15C burst charging (during re-gen braking), we raise the voltage at the tabs of the cells beyond 5v at times. It simply raises to whatever the Ri (internal resistance) * the charge current happens to be. Other than the normal cell heating (Ri*I^2), there is no concern to raise cell voltages beyond the SOC cut-off voltage during charging. As long as the SOC voltage doesn't exceed the safe HVC level, there is no risk or damage, as the chemistry inside the cell has not reached an unstable condition, and the separator layers always seem to have a margin of safety around 10x the insulation needs of the HVC for the cell. 

The charge algorithm they use is a more advanced and more desirable method for rapid charge than just CC/CV, as inherently the CV stage always concludes with a charge rate approaching zero as cell SOC approaches HVC. It's listed on battery sheets because it's simple and full-proof. It's the cheapest charger setup to make. 
These chargers that interrupt charging to sample voltage with a A-D in a uController, then re-apply a charge current for a few seconds, then sample SOC voltage again are much more advanced, much faster, and just as safe as slower CC/CV charging methods.


----------



## Tuikku (Apr 7, 2010)

*Re: Running tests on the WF-139*

Thanks for your information mdocod!
I must measure some voltages when I get my charger.



HKJ said:


> I have been using a couple of WF139 on 230VAC for some time now, without any problems.



Hmm... Could it be that my friends apartment has some power surges or something like that.




Font size said:


> *From what I read here the 123 are not supposed to be used on the WF-139 charger.
> * *[FONT=&quot]A low capacity cell, which was NOT identified in the charger specifications, often demonstrates an overvoltage while under charge.***[/FONT]



Good to know this!
I can use my sku1236 Ultrafire instead of it now that I know. Thanks.


----------



## 45/70 (Apr 7, 2010)

liveforphysics said:


> As long as the SOC voltage doesn't exceed the safe HVC level, there is no risk or damage, as the chemistry inside the cell has not reached an unstable condition, and the separator layers always seem to have a margin of safety around 10x the insulation needs of the HVC for the cell.




Interesting ideas, live.

If first tier cells were used, I might be convinced of this. I have to admit however, that I'm a bit skeptical of pushing the safety margins when it comes to Li-Ion cells, particularly when the user group, at least in part, is totally unaware that any safety margin is being pushed.

As I said, if first tier cells were involved, this may all work out fine. Practically all the Li-Ion cells we use in flashlights though, are not first tier cells. Most loose Li-Ion cells that we obtain are cells that were, for one reason or another, rejected by the cell manufacturers for use in manufacturing packs. These cells could have been rejected for any number of reasons, low capacity, high capacity, or in some way, just not meeting the required specifications.

When a cell doesn't meet spec, you have to wonder why? Likely, it is because of a physical anomaly in the cells construction, or a chemical imbalance in the cells chemical makeup. Considering these possibilities, that 10x safety margin you mention, could be diminished to practically none. Add to that, the general QC inconsistencies in most available Li-Ion chargers , and I think you'd have a real problem. Poor QC charger + defective cell = problem.

Until the the actual Li-Ion cell manufacturers make available "first tier" loose Li-Ion cells at the consumer level, which I seriously doubt they will ever do for liability reasons, I don't think this charging method would be a good idea for "the casual user". For those of us that actually know and understand the potential dangers, it's a different story. 

Dave


----------



## jirik_cz (Apr 7, 2010)

Tuikku said:


> I didn´t know about this problem BUT I heard from my friend about problems, when using it with 230VAC. Naturally, this problem doesn´t affect most of CPF users, since you have 110VAC.
> 
> These chargers tend to burn their circuits when used in 230VAC.



There are at least three versions of WF-139 chargers. And they probably come from different manufacturers. The version sold by AW has no problems with 230VAC.


----------



## liveforphysics (Apr 7, 2010)

Call it interesting, or call it the industy standard for professional battery management. If you get a bad cell, you get a bad cell. That doesn't mean its wrong to charge exactly the way this charger does it. As long as it doesn't leave the SOC on a cell over 4.2-4.3 when you pull the cell off the charger, its not doing a thing wrong, or imposing any danger to the cell or user that would not be equally present with a slow CC/CV curve.

This is a premium feature of a charger, it shocked me 4 years ago when I discovered they used this complex and costly charging method to shorten charge times, but I was pleasently surprized by it. I've had cells sitting in the first gen WF-139 for months at a time, and as long as there is no charger malfunction, there is no risk. However, if there is charger malfunction, it doesn't make a difference what the intended charge method happened to be prior to the malfunction does it? 


-Luke





45/70 said:


> Interesting ideas, live.
> 
> If first tier cells were used, I might be convinced of this. I have to admit however, that I'm a bit skeptical of pushing the safety margins when it comes to Li-Ion cells, particularly when the user group, at least in part, is totally unaware that any safety margin is being pushed.
> 
> ...


----------



## 45/70 (Apr 7, 2010)

liveforphysics said:


> Call it interesting, or call it the industy standard for professional battery management.



I'm curious, what industry are you referring to?



> This is a premium feature of a charger, it shocked me 4 years ago when I discovered they used this complex and costly charging method to shorten charge times, but I was pleasently surprized by it. I've had cells sitting in the first gen WF-139 for months at a time, and as long as there is no charger malfunction, there is no risk.


I'm a bit confused here. The WF-139 is one of the slowest 18650 chargers available. It would appear that it's method of charging isn't helping it to charge any faster.

As far as leaving Li-Ion cells on any charger, beyond charge completion, it's not a good idea, and I certainly wouldn't recommend that others do so. It's just a really bad practice.

Dave


----------



## Tuikku (Apr 7, 2010)

jirik_cz said:


> There are at least three versions of WF-139 chargers. And they probably come from different manufacturers. The version sold by AW has no problems with 230VAC.



Ok! :twothumbs


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## march.brown (Apr 7, 2010)

45/70 said:


> As I said, if first tier cells were involved, this may all work out fine. Practically all the Li-Ion cells we use in flashlights though, are not first tier cells. Most loose Li-Ion cells that we obtain are cells that were, for one reason or another, rejected by the cell manufacturers for use in manufacturing packs. These cells could have been rejected for any number of reasons, low capacity, high capacity, or in some way, just not meeting the required specifications.Dave


 
If a particular company orders for example 10,000 (first tier) cells (or batteries) from the manufacturer , the manufacturer obviously makes more than this to allow for a percentage of rejects ... If they make 10% more than ordered , they know that these spares can be offloaded quite easily to other bulk buyers ... The (in this case) 1000 spares could comprise perfectly good (first tier) cells and some rejects ... So you could be lucky and get perfectly good cells from a cheap source.

I am not certain how many companies manufacture (for example) 18650 cells and are they all located in the Far East ? ... It would be interesting to know this ... Also , as a lot of these spare cells are converted to protected cells , there must be a few companies that specialise in this operation too ... Perhaps one company supplies to all the ****fire sellers ... Again , it would be nice to know who and where.

It is a shame that the original manufacturers don't sell individual protected cells too ... I wonder who AW get the cells from ... The original manufacturer or the second line companies.

Is every cell tested or just a percentage ? ... Does the manufacturer test all the cells ? ... Does the company that adds the protection circuit test all the cells ? ... Does AW test all the cells ?
.


----------



## mdocod (Apr 7, 2010)

Hello Luke,

For the last year or so I have in various places admitted that whether or not charge voltages in excess of 4.25V is "bad" for li-ion cells is still up for debate. 

I have yet to see a study performed that would prove anything either way. Up until now, and continuing forward until I have proof in hand, I will continue to point out that a CC only charge method with charging voltage (_not_ state of charge) exceeding 4.25V is not listed as a recommended or acceptable charge method by the manufactures of these cells. 

I'd like to see a study that has run cells through hundreds of cycles, some charged CC/CV (with true current based termination, no trickle), and others charged CC only with intermittent SOC testing like the WF-139 (also with absolute termination, no trickle, much like the later generation 139s). 

I figure, to be fair, the charging rate of each charger to be tested should be calibrated such that charge time to termination is within +/-5% (the "average" charge rate of each would have to be the same for this to work). 

I would want to set it up to run repeating charge and discharge cycles for weeks, maybe months on end. Maybe an hour between cycles (short rests) and a 48 hour rest once per week to determine where the cell is settling to as it ages, All cycles should be plotted and graphed and stored. Ideally, the test should be duplicated across at least a handful of cells to confirm the results and reinforce any trends. 

If after a few hundred cycles, both cells show equal capacity and state of charge after their resting periods, then I would be satisfied that the CC only charging method is perfectly acceptable, and we could put this issue to rest once and for all.

Setting up such a test would require building some temporary custom chargers, or modifying existing ones, but it could probably all be done on a test board or something like that. 

I with I had the time and money, I would set up the study myself. 

My gut tells me that knowing the answer to this question would be useful for any manufacture that builds a product that uses a li-ion cell. Being able to advertise faster charge times as a result of using a CC-only charge would be great as long as it was proven safe. Perhaps someone has already done such a study. 

Lets start scouring the net and see what we come up with eh?

--------

PS: You are absolutely correct that in a charger that has been confirmed to terminate, you can leave cells on it as long as you want and it shouldn't be a problem (provided the charger doesn't malfunction for some reason).

Best practice will be to continue to recommend against leaving cells on chargers because most people are not going to take the time to verify if the charger they own actually terminates: always remember, a WF-139 bought today could be different than the one bought yesterday  (Or any other model charger for that matter). 

In one of the WF-139 test threads here on the forum, it was demonstrated that if the charge is re-initiated on a cell that is very close to 4.20V, (by removing the cell and reinserting after termination), The charger will completely miss the current ramp down algorithm and termination all together, it will charge at 350mA until it runs out of over-head voltage in the circuit to work with. (It would try to take SOC to ~5V). With that in mind, and the possibility that a blink in the power could re-initiate a charge on your WF-139, are you still going to leave cells sitting on there?

Also, first gen WF-139s would apply a CC trickle after the light turned green that had no real upper end limit to how high it could take a cell either. (open circuit voltage of that unit was ~11V, so I suspect that the cell would rise to whatever voltage could be maintained by that trickle rate, obviously as a cell is over-charged, more and more of the energy going in is converted to heat, The SOC could theoretically peg out to dangerous levels on smaller cells. 

Eric


----------



## 45/70 (Apr 7, 2010)

march.brown said:


> If a particular company orders for example 10,000 (first tier) cells (or batteries) from the manufacturer , the manufacturer obviously makes more than this to allow for a percentage of rejects ... If they make 10% more than ordered , they know that these spares can be offloaded quite easily to other bulk buyers ... The (in this case) 1000 spares could comprise perfectly good (first tier) cells and some rejects ... So you could be lucky and get perfectly good cells from a cheap source.



Hi march.

I'm sure this is true and not all cells from distributors are "seconds". That no doubt adds to the "hit and miss" factor with these cells.



> I am not certain how many companies manufacture (for example) 18650 cells and are they all located in the Far East ? ...


Yeah, seems like it. Most of the "good cells" appear to come out of Japan or Korea, or their subsidiaries in China.



> It is a shame that the original manufacturers don't sell individual protected cells too ... I wonder who AW get the cells from ... The original manufacturer or the second line companies.


I don't think they ever will. Cell manufacturers don't make protection circuits period, because they see the liability factor as just being too great. As I and others have pointed out, making a protection circuit for a specific device (as the pack makers do. Keep in mind that these makers have to demonstrate how they are going to build the pack and utilize a protection circuit before the cell manufacturer will provide cells to them) is pretty simple, but coming up with one that will work equally well for a single 5mm LED light, as well as a 250 Watt hotwire is impractical.

As for AW, I have no idea, but however he obtains them, he must be getting close to first tier cells. I suspect he has some connections that allow him to get "first pick". This no doubt costs him more and would also explain why his cells are more expensive.



mdocod said:


> I'd like to see a study that has run cells through hundreds of cycles, some charged CC/CV (with true current based termination, no trickle), and others charged CC only with intermittent SOC testing like the WF-139 (also with absolute termination, no trickle, much like the later generation 139s).



Don't you think the Li-Ion cell manufacturers have already tested various charging methods? I doubt however, that they used a WF-139.  It would certainly be in their best interest to make recommendations that benefited their product. I agree though, I'd like to see the results of such tests.

Dave


----------



## liveforphysics (Apr 8, 2010)

45/70 said:


> I'm curious, what industry are you referring to?
> Dave


 

My real day job is megawatt scale UPS and power filtering design for Datacenter/Telco applications. 

My side work is EV power system design and management. For example, updating the mavizen TTX02 to run LiCo Polymer rather than heavy/bulky LiFePO4 with the ability to rapid charge between heats.

http://www.mavizen.com/Bikes_and_Kits/TTX02.html

The Tesla roadster also uses this same battery charging method rather than CC/CV. 

I also do light EV battery system design. Like E-bikes, E-boats, E-scooters etc. Here is a little 64mph bicycle I use to commute when the weather is good. 











45/70 said:


> I'm a bit confused here. The WF-139 is one of the slowest 18650 chargers available. It would appear that it's method of charging isn't helping it to charge any faster.


 
It's slow because of the low current settings to let it charge a wide variety of Ri/capacity cells safely. But it's only half as slow as a charger just using CC/CV with equally low/safe charge current would be.  Adding another resistor in parellel over the shunt doubles the charge current, and retains the neat charging method if your looking to speed things up. 



45/70 said:


> As far as leaving Li-Ion cells on any charger, beyond charge completion, it's not a good idea, and I certainly wouldn't recommend that others do so. It's just a really bad practice.


 
Just curious, has anyone out there, even just somebody posting a comment on DX, anyone at all ever had this model of charger cause more than a non-flame solvent vapor venting (if that has even happened)? And would this venting of a damaged cell not have happened with any other charger?


----------



## liveforphysics (Apr 8, 2010)

mdocod said:


> Hello Luke,
> 
> For the last year or so I have in various places admitted that whether or not charge voltages in excess of 4.25V is "bad" for li-ion cells is still up for debate.
> 
> ...


 
Wow! There are only hundreds, maybe thousands of these studdies published! LOL Both independent and manufacturer conducted studdies, and for LiCo, LiMnCo, LiFePO4, liquid-E, polymer-E, dual carbon current collectors, just carbon anode current collectors, and everything in between. lol 

Here is an example:





http://www.kokam.com/product/images/lipo_img_03.gif








Often a 10x extension of cell life is reported from an HVC of 4.125v vs 4.25. This is why we charge to 4.1v for all normal use charge cycles, and charge to 4.3-4.4v for performance critical applications (where energy density is more critical than >N-cycle).





mdocod said:


> In one of the WF-139 test threads here on the forum, it was demonstrated that if the charge is re-initiated on a cell that is very close to 4.20V, (by removing the cell and reinserting after termination), The charger will completely miss the current ramp down algorithm and termination all together, it will charge at 350mA until it runs out of over-head voltage in the circuit to work with. (It would try to take SOC to ~5V). With that in mind, and the possibility that a blink in the power could re-initiate a charge on your WF-139, are you still going to leave cells sitting on there?


 
I normally pop them up and re-seat them to have it raise the SOC a bit higher before using them in my flashlights. For a flashlight, the cell cost is almost nothing, and anyone can afford to keep 3-4 cells for a light. Do the math on the cycles/lifespan, and you'll find you're killing your cells faster from having them sit on the shelf.  The convience of having the ability to have another 10mins of light is well worth the difference in getting 700 cycles or getting 400cycles IMO. 




mdocod said:


> Also, first gen WF-139s would apply a CC trickle after the light turned green that had no real upper end limit to how high it could take a cell either. (open circuit voltage of that unit was ~11V, so I suspect that the cell would rise to whatever voltage could be maintained by that trickle rate, obviously as a cell is over-charged, more and more of the energy going in is converted to heat, The SOC could theoretically peg out to dangerous levels on smaller cells.
> 
> Eric


 
Any charger that applies any current to the cell beyond it's own self-discharge (~uA) rate is a defective charger. I'm not sure how much earlier of a version of the WF-139 they make, but I'm happy to say I've not personally seen any WF-139's that trickle. If someone were to observe this, the charger should be thrown out like any other defective charger. 

As far as the open circuit voltage, I don't hold any devices cell-presense-senseing voltage over it.


----------



## march.brown (Apr 8, 2010)

liveforphysics said:


> For a flashlight, the cell cost is almost nothing, and anyone can afford to keep 3-4 cells for a light. Do the math on the cycles/lifespan, and you'll find you're killing your cells faster from having them sit on the shelf.  The convenience of having the ability to have another 10mins of light is well worth the difference in getting 700 cycles or getting 400cycles IMO.


.
My 18650s probably get topped up about once a month ('ish) , maybe a bit more in the winter months and less in Summer ... This is probably much less than 20 times a year ... If a cell has a life of say six years then I would be topping-up/recharging an absolute maximum of 120 times , so I am not too worried about whether it is capable of 700 or 400 cycles ... Since I have a few spares then these figures can virtually be halved ... So all my cells might only be charged 60 or so times in their life.

I can see that someone that uses his torches every day for several hours will be in a different situation to this and would benefit from using a 4.1 volt ceiling to get the maximum number of cycles ... But that type of user is likely to have at least two or three cells per torch ... The probability is that the cells will still die of old age rather than running out of charging cycles ... Obviously there are exceptions to the rule , but the average torch-users cells will probably still die from old age.

I will probably just buy four new (Ultrafire) cells every three or four years ... That is not a huge expenditure really ... It works out at a cost of one cell per year ... That's cheap for what I get out of them.
.


----------



## mdocod (Apr 8, 2010)

Hello Luke,

Most of us here are quite familiar with the studies that have shown that lower termination voltages result in better cycle life. You must have misunderstood what I am looking for. 

Assuming termination voltages are equal, but one charger is achieving them through constant current with voltage testing every 1-2 seconds (which involves charging voltage in excess of the target termination voltage by a fairly large margin), like the wf-139, and another charger operating with a standard CC/CV charge method whose charging voltage will never exceed a few hundredths of a volt above the final termination voltage of the cell. Of these 2 charging methods, which one degrades cells more quickly?

I'm not concerned with which termination voltage would be chosen to conduct this test, anything within reason. If anything, it might be best to choose a higher termination voltage to speed along the cycle testing faster because we are *not* looking for information about the effects of termination voltage, we are looking for information about the effects of the different charging methods that get us to those termination voltages. 

If you can shed any light or point to a study that has done this I would greatly appreciate it. 

----

It is the charger that was tested in the first post of this thread that continues to trickle above and beyond the termination point. 

I can still use the charger for RCR123s, because with those cells, the PCB terminates the charge at 4.15V SOC (4.35V charging voltage), and holds the circuit open until something changes. I try to avoid using that charger because I don't trust it, but when I have lots of cells that all need charging at once, I'll put lots of these poorly made chargers to work under supervision.

Eric


----------



## 45/70 (Apr 8, 2010)

liveforphysics said:


> My real day job is megawatt scale UPS and power filtering design for Datacenter/Telco applications.
> 
> My side work is EV power system design and management. For example, updating the mavizen TTX02 to run LiCo Polymer rather than heavy/bulky LiFePO4 with the ability to rapid charge between heats.
> 
> ...



OK, Luke, I suspected there might have been an industry mix up. In the Li-Ion cell industry the recommended charging algorithm is CC/CV with charge termination at 0.03C. In the EV industry, I'm not surprised that different methods are explored for efficiency reasons. This is how new ideas are, developed, implemented, improved etc.

Here on CPF we are concerned with the use of Li-Ion cells in flashlights, not EVs (although many of us are interested, including myself) so, we tend to lean towards the Li-Ion cell manufacturer's recommendations.



> It's slow because of the low current settings to let it charge a wide variety of Ri/capacity cells safely. But it's only half as slow as a charger just using CC/CV with equally low/safe charge current would be.


I have seen several tests of the WF-139 and compared them to other chargers, such as the Pila IBC. From mdocod's other current thread, for example (from post #1),



> Cytac CY-015: [email protected] minutes
> 1st Gen WF139: [email protected] minutes
> Cytac Digital 2x18650: [email protected] minutes
> Pila IBC: [email protected] minutes
> YOHO-122: [email protected] minutes


even though the Pila is charging at 600mA and the WF-139 at 450mA (due to poor QC this seems to vary between units), I don't see it offering any advantage over the Pila, and actually appears to be less efficient. I might add that mdocod used cells discharged to 3.70 volts for this test. This means that the Pila's CC stage would have been shorter than if the cell were completely discharged to ~3.5-3.6 Volts, resulting in a shorter 600mA CC stage.



> Just curious, has anyone out there, even just somebody posting a comment on DX, anyone at all ever had this model of charger cause more than a non-flame solvent vapor venting (if that has even happened)?


I think it has, but the point here is to prevent such incidents. I'm not saying that I disapprove of _your testing_, I don't, but for the average user who is not familiar with charging Li-Ion cells, "incidents" are best avoided, IMO.

This brings us back to which algorithm for us to use, the Li-Ion cell manufacturer's, or the EV industry's which, while being out of the alpha stage, I think is still considered to be in the beta stage. I vote for the Li-Ion cell manufacturer's, considering that the cells and chargers used by the CPF community are likely not up to Tesla's quality standards, but especially in the case of xxxxxFire et al, more like Yugo's standards (tow truck merits not considered in the evaluation ).

Dave


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## liveforphysics (Apr 8, 2010)

45/70 said:


> OK, Luke, I suspected there might have been an industry mix up. In the Li-Ion cell industry the recommended charging algorithm is CC/CV with charge termination at 0.03C. In the EV industry, I'm not surprised that different methods are explored for efficiency reasons. This is how new ideas are, developed, implemented, improved etc.
> 
> Here on CPF we are concerned with the use of Li-Ion cells in flashlights, not EVs (although many of us are interested, including myself) so, we tend to lean towards the Li-Ion cell manufacturer's recommendations.
> 
> ...





I made sure to mention the Tesla, as it uses liquid electrolyte LiCo 18650s. Same type of cells you run in your flashlights, only 3831 of them rather than 1-2. 

I think it's safe to say, 10x more money has been invested just in testing pack and pack charging for the Tesla alone, than in the history of all flashlight and flashlight charger RnD since the beginning of flashlight history. 

Part of bringing a $36,000 battery pack onto a production scale that needs to meet minimum N-cycle levels and be under warranty means testing the charging algorithm is part of the game plan...

There are also a whole market of advanced BMS ICs and uControllers with millions of dollars in production costs designed around the implementation of this charge method. 



Let's break this down just with some simple logic.

Charging is an electro-chemical process. Think about it as such. You can add the energy to relocate a lithium ion with an electron. It's the current, and the current only that charges a battery (not voltage). Current can not flow without a voltage difference, this is the reason for having a charge voltage. For example, is it possible for a 4.2v CV stage to bring a cell to a 4.2v SOC? No. It can get infinitely close given infinite time, but the limit is inherently <4.2v SOC. This tapering of the addition of current is not needed if you increase charge voltage as needed to maintain current, and interrupt to check SOC. Voltage on the terminals of the cell isn't the risk, it's the state of the chemical process inside the cell that poses the risk, and the SOC is the indicator of this state. 

I feel like I'm beating a dead horse here, and I once used to feel exactly the same way you guys do about charging (and CC/CV is the idiot-proof, dead simple method), so I don't judge you guys for thinking the way you do. 

I'm going to fade off of this topic, because I've said my piece, and it's a free world to include or exclude whatever charge methods a person wants to be involved with. 

Best Wishes,
-Luke


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## Font size (Apr 9, 2010)

*Re: Running tests on the WF-139.*




45/70 said:


> Here on CPF we are concerned with the use of Li-Ion cells in flashlights, not EVs, so, we tend to lean towards the Li-Ion cell manufacturer's recommendation.


 Well I guess that settles it for sure, we tend to lean towards the Li-Ion cell manufacturer's recommendation.

AW tells us the Wf-139 charging method is OK for his cells.  [FONT=&quot]


AW said:


> "WF-139 is OK (newer version that terminates at 4.2V +/- 0.05V). I have done testing with over 50 pcs. of them and none of them charges above 4.25V."


 Anyone using what we here on CPF think are the highest quality cells, can go on using the Wf-139 chargers with AW cells as per our Li-Ion cell manufacturer's recommendation.[/FONT]


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## 45/70 (Apr 9, 2010)

*Re: Running tests on the WF-139.*



Font size said:


> Well I guess that settles it for sure, we tend to lean towards the Li-Ion cell manufacturer's recommendation.
> 
> AW tells us the Wf-139 charging method is OK for his cells.  Anyone using what we here on CPF think are the highest quality cells, can go on using the Wf-139 chargers with AW cells as per our Li-Ion cell manufacturer's recommendation.




While AW is a provider of some of the best cells available, and can endorse the use of the WF-139 if he so desires, he is a distributor, not a manufacturer. Cell manufacturers recommend charging with a CC/CV algorithm, which the WF-139 does not use.

Dave


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## VidPro (Apr 9, 2010)

i think there are some missed points here about CC vrses CV on the end of charge
It was pointed out that this is a chemical reaction thing going on.
but yet the understanding of the chemical reactions (many many of them inside there) eventually being finished mostly.

i tend to look at a charging alogrythm Much differentally, from what my batteries have said about them 

When 90% of the chemicals are at the uncharged state, pushing a HIGH rate in is pushing a LOT of chemicals into thier charged state , there exists a pile of chemicals ready to change over. a pile of charge acceptance.
when only 10% of the chemicals are Left TO charge up, my batteries say that you shouldnt be trying to charge that LAST LITTLE BIT of stuff at the same crasy rates you could have used at the beginning. limited charge acceptance.
(of course with low rates to begin with, this isnt a problem)

put this into a pitri dish and when you slam it with the power , the chemicals that are in one state, will switch easily to the other state. but when there is only a few chemicals LEFT to change, and you maintain the same current, pitri dish components get all charred  before the last few uncharged chemicals hiding in the corners change up 

for me the perfect charge alogrythm slows down or speeds up* a Rate relative to the quantity of chemicals* that still need to be turned.
anything else is just Winging it as best as it can.
Some stuff at least TRIES to work along the lines of slowing down for the last stubborn movement to finish up. some stuff is just half blind power.

so 1 stage charger is a beginning, 2 stage charger is a good try, 128 stage charger We didnt even ASK for yet 
if you want great speed of charge, then like other highly tested half blind speed charge methods, they just dont even bother charging the last little bit. (90% charge)

all these tests from various places, will USE Constant current, then give results for a charge style, BLIND to the chemicals results, then say they understand chemicals?
but ye old Voltage controled or staged current testing taking longer to do, which takes the quantity of chemicals Left to charge into Account, instead of being Blind, and where are Those results? 
i am saying that sometimes the LABs can be Stuck on thier methods, standards, and precision, and completely miss reality. reality is the chemicals indeed.

The new theory of relativity


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## liveforphysics (Apr 9, 2010)

Vidpro- It's very simple to see how well a cell is accepting charge. Whichever point has the lowest Ri is the point at which it completes the conversion of current to stored chemical efficiency with the greatest efficiency. You will find it's almost inverse of what you described... 

Which brings about another charge method adaption. Constant heat charging/ constant efficiency charging. It can't be done with a CC/CV profile, but if your uController samples the on-current voltage difference with the SOC voltage each time it samples SOC, it can adjust current to maintain a fixed safe amount of cell heating rate, and/or a fixed chemical conversion efficiency rate. 

Our 36 channel DIY BMS setup is able to do this type of chargeing as well. 












But, I will leave this thread to the charger pros 

Best Wishes,
-Luke


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## VidPro (Apr 9, 2010)

liveforphysics said:


> You will find it's almost inverse of what you described...
> 
> -Luke


 
how is that the inverse of what i described?
are you saying that a battery is more capable of accepting a charge WHEN 90% of the chemicals are switched?

are you suggesting charging a battery at a HIGHER rate, when its mostly charged, and at a Lower rate when it is mostly discharged?

make me a pro  i am willing to learn more info.

in 1973, i delivered papers on a hand built electric minibike, EVs are awesome , but things do change, i guess i need a whole computer now to charge a battery, gonna have to learn more.


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## liveforphysics (Apr 9, 2010)

VidPro said:


> how is that the inverse of what i described?
> are you saying that a battery is more capable of accepting a charge WHEN 90% of the chemicals are switched?
> 
> are you suggesting charging a battery at a HIGHER rate, when its mostly charged, and at a Lower rate when it is mostly discharged?
> ...


 

A cell can accept the charge current as efficiently as possible when the Ri is lowest. Ri varies inversely with cell temperature, but does not have any direct relationship with SOC until the cell close to discharged. 

In other words, when a cell is deeply discharged, it's ability to accept charge charge is least efficient. AKA, most cell heating from a given current value, AKA most cell damage from a given current value. 

Again, for a flashlight though, this entire conversation is academic. In practice, if the charger doesn't take cells over 4.25-4.35v, then it simply doesn't matter the charge method. The cells are dying faster from sitting on the shelf than from cycles, and in a EDC full-cycleing daily application, the investment of another $4 cell yearly is a reasonable expense to justify...


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## VidPro (Apr 9, 2010)

*it's ability to accept charge charge is least efficient. AKA, most cell heating from a given current value*

ahhh, i see, makes perfect sence, can i see the graph for a same given current charge on a battery where the temperature doesnt go up ?

i think i found one that shows the Spike in temperature Increases relative to the total temperature ramping up, right at the beginning of charge, when the charge was just starting out. it seemed logical that when the waste heat began in the cell, that it was visualised as a spike from room temperatures, when the temperature probe on the outside of the battery finnaly saw what was occuring inside.

mabey it has something to do with me living in california, and it being rare that we do things like put heaters on batteries to make them more active ??? you know trying to keep them down, vrses having to raise them to get anything even going?

*Again, for a flashlight though, this entire conversation is academic.*

oh yes, flashlights are nothing compared to the massive power needed for an EV, wowsey wowser , unless you include the guys with the 5 minute 130,000 candle power light, and the crasy dude running the microwave plasma light, the guy with the tank light, and the many hotwire people who seem to think 5 minute runtimes on batteries are long runtimes.
I am sure that draining a huge battery in 1 hour on an EV really doesnt compare :thumbsup:

we are not worthy :bow::bow::bow::bow: not worthy

we do academic too, please show me the graph where the current is the same and the temperature drops, it would be very educational, even school like.


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## 45/70 (Apr 9, 2010)

liveforphysics said:


> I made sure to mention the Tesla, as it uses liquid electrolyte LiCo 18650s. Same type of cells you run in your flashlights, only 3831 of them rather than 1-2.
> 
> Part of bringing a $36,000 battery pack onto a production scale



The last I knew, which was admittedly a year or so ago when the Roadster was just hitting the road, they used 6000+ 18650 cells and the packs were around $20,000. Somewhat later, I heard the price was down to $15,000. Perhaps the cost reduction has to do with them actually being in, more or less, normal production now.

I ran a quick computation once, to figure out what just the cost of the electricity used to charge the pack along with the cost of replacing the pack every five years was, and came up with 67 cents per mile. This was based on, (I think) 12,000 miles driven per year. I may have that wrong, but it made my '73 Vette cheaper to drive up until gasoline got to about $10 per gallon. This didn't include other maintenance though, which would hopefully anyway, be very minimal with the Tesla. 

I hope you understand, live, and you do seem to, that I am not necessarily in conflict with you on the charging method and am just pointing out some of my, and other's views here on the Forum, and the reasons behind them. I can just see someone reading your posts and taking a well seasoned crappy LiCo cell and trying to charge it at 12 Volts ("Hey, if 5 Volts works, wouldn't 12 work better?") with an equally crappy random wall wart PS, some coat hanger wire, and running into problems. 

Without guys like you experimenting with new ideas (and old as well) the whole picture would become stagnant. So, keep up the R&D! :thumbsup:

My apologies mdocod, for straying waaay OT. 

Dave


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## liveforphysics (Apr 9, 2010)

45/70 said:


> The last I knew, which was admittedly a year or so ago when the Roadster was just hitting the road, they used 6000+ 18650 cells and the packs were around $20,000. Somewhat later, I heard the price was down to $15,000. Perhaps the cost reduction has to do with them actually being in, more or less, normal production now.
> 
> I ran a quick computation once, to figure out what just the cost of the electricity used to charge the pack along with the cost of replacing the pack every five years was, and came up with 67 cents per mile. This was based on, (I think) 12,000 miles driven per year. I may have that wrong, but it made my '73 Vette cheaper to drive up until gasoline got to about $10 per gallon. This didn't include other maintenance though, which would hopefully anyway, be very minimal with the Tesla.
> 
> ...


 

Dave- Thank you for your kind words.  Myself and the teams I work with all firmly share your thoughts towards R&D.  


As far as the number of cells in the Tesla pack. Oops! I fumble-fingered the 10key pad and landed a key down for a 3 rather than a 6. 

You're absolutely right, it's 6,831 cells, not 3,831 cells. 

As far as pricing goes, it was $36,000 for Tesla Motor's cost on a pack as of Feb 2009. They offer a pay-now for later pack replacement plan that is 1/3rd of that cost, banking on battery technology continueing to rapidly drop in price. It's not currently dropping as quickly as it needs to... lol 
http://blogs.edmunds.com/greencarad...placement-would-be-36000-today-musk-says.html
I don't know if it's offically public yet, but they've also changed to a 4Ah 18650 cell (yes, 4,000mAh, not a typo) for the new packs, which enables them to run about 1/3rd less cells, and shave a few hundred pounds off the pack.  


I can fully understand not wanting to encourage people to charge with a coat-hanger and a wall-wart. lol. If I've done that, I must admit it was not my intention. 

As flashlight battery charger design catches up, you will see all chargers charge like the WF-139. It's a little more costly to setup, requires u-Controllers and programming rather than a simple analog circuit, but the advantages make it worth the extra trouble for any time-critical charge applications. 


Best Wishes,
-Luke


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## VidPro (Apr 9, 2010)

liveforphysics said:


> I don't know if it's offically public yet, but they've also changed to a 4Ah 18650 cell (yes, 4,000mAh, not a typo) for the new packs, which enables them to run about 1/3rd less cells, and shave a few hundred pounds off the pack.
> Best Wishes,
> -Luke


 
wow, and them flashlight people have only been using 4800ma (not a typo and actual capacity) and some 6000ma 32650 li-ion cells , for only 5+ years Officially public 5 YEARS AGO. 1/3rd less cells and shaves nothing off the pack. plus some have used li-fe 4000ma , and even 32amp Li-Fe and everything else that has come about in battery technology, when it is available.
guess the almighty tesla catches up eventually 

see flashaholics arent some cavemen to batteries either, so please dont treat us that way. 
:welcome:


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## liveforphysics (Apr 9, 2010)

VidPro said:


> wow, and them flashlight people have only been using 4800ma (not a typo and actual capacity) and some 6000ma 32650 li-ion cells , for only 5+ years Officially public 5 YEARS AGO. 1/3rd less cells and shaves nothing off the pack. plus some have used li-fe 4000ma , and even 32amp Li-Fe and everything else that has come about in battery technology, when it is available.
> guess the almighty tesla catches up eventually
> 
> see flashaholics arent some cavemen to batteries either, so please dont treat us that way.
> :welcome:


 

LOL! 

Not a member on this forum has ever even held a 4Ah 18650 cell, and it will likely be another 2 years before the samples even reach the flashlight market. 

Of course there are physically larger cells with larger capacity... 800Ah LiFePO4 is the largest single cell I've worked with to date, but there are 2,400Ah lithium cells out there on the market. I don't know if you caught my lithium destructive testing videos, but I toast some 10Ah, 15Ah, 20Ah, and 40Ah cells for hazard testing. 

The significance is that it's 4Ah in a 18650 package size... 


*edit* I found somebody on light-reviews who commented on the very cells Tesla's new pack design uses.  This is saying 2013 for public release. My 2 year guess was close. 

http://www.light-reviews.com/forum/viewtopic.php?f=15&t=786


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## VidPro (Apr 9, 2010)

liveforphysics said:


> LOL!
> 
> 
> The significance is that it's 4Ah in a 18650 package size...


 
the significance is tesla is still using cells made for laptops and cameras  and some flashaholics have applied batteries that would work good in an EV, So freaking what. 

as far as your tests, *they show significant lack of any safety procedures followed*, and blatently obvious faults in handling of the materials, as if the handler has no idea what they are doing, or even what they are made of.
Basically proved to many of us here, that you have not been a member of this forum for long. and obviously werent doing the testing in a atmosphere that is fit for any professional lab, or even following any logic for the chemicals that exist within the cell items.

so AGAIN, quit being so condescending. were all here basically trying to learn and do some of the same stuff, transferring valuable information data and thinking across the cyberspaces. 
that scooter you showed, is some awesome setup, with the li-fe on it, sure would like to see more of it. what method of protection balancing and charge is that using?

and where is that temperature graph, that shows a decrease in heat you were going to show us?


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## liveforphysics (Apr 9, 2010)

VidPro said:


> the significance is tesla is still using cells made for laptops and cameras  and some flashaholics have applied batteries that would work good in an EV, So freaking what.
> 
> as far as your tests, *they show significant lack of any safety procedures followed*, and blatently obvious faults in handling of the materials, as if the handler has no idea what they are doing, or even what they are made of.
> Basically proved to many of us here, that you have not been a member of this forum for long. and obviously werent doing the testing in a atmosphere that is fit for any professional lab, or even following any logic for the chemicals that exist within the cell items.
> ...


 

You're right. Everybody wants to cut open and destructively test cells indoors in a lab. It's a much better idea to do it indoors, maybe in a fume-hood with a tempered glass pannel to break...


I've been a member here for 4 years. I guess that is new in your mind?

I'm being condecending, yet you're the one complaining about safety of tests conducted in destructive cell tests... lol Failing batteries aren't that dangerous until you load them into a flashlight and turn what would be a pop of gas/flame venting event into something like a life threatening pipe-bomb. 


As far as a cell graph goes, first you must understand the difference between temperature and heating. One is a quanity, one is a rate. 
Second, I'm not trying to teach electronics 101 here. The formula for cell heating is the same as the forumula for any other resistive heating, and I listed it above all ready. I^2*Ri. If you can't see that internal resistance has an inverse-linear relationship with heating during CC charging, then I don't know what to tell you. It happens to be the exact same formula for cell discharge heating as well... or a simple resistor...

Anyways... I'm going to try harder at fading away now... Continue on full-throttle with spreading fear of any alternate charge methods. I won't bother to try to shine a light into the darkness any more here. 

Darkness+fear = Winner. 



-Luke


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## VidPro (Apr 9, 2010)

but we need your light.

just didnt need to be treated like were hopeless.


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## JaguarDave-in-Oz (Apr 9, 2010)

liveforphysics said:


> I'm being condecending, yet you're the one complaining about safety of tests conducted in destructive cell tests...
> 
> Anyways... I'm going to try harder at fading away now... Continue on full-throttle with spreading fear of any alternate charge methods. I won't bother to try to shine a light into the darkness any more here.
> 
> Darkness+fear = Winner.


Hang around a bit more please, some of us are getting something out of what we've been reading from you.

Once those with an opposing view start up with insult and begin playing the man and not the ball it tends to make the reader think it's a diversion form an argument they can't make hold water so don't let the insults deter you.

How long you've been a member is of no importance, there's no credence lent by a join date, the only thing that matters is the quality of what a poster writes. You're doing fine.


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## VidPro (Apr 10, 2010)

the insults come from the totally incorrect information, 3rd grade electronics BS tossed about, that do not support his false information at all. trashing flashaholics with his condescending attitude , and making believe that Candlepower forum members are beyond his information.

the reason i question his term of existance in the forum, is because when doing testing with no face shield, clowning around with batteries about to ignite, and not wearing gloves, OTHER persons (not him) displaying thier Lax procedure and total disreguard for what they were teaching others , got REAMED for being fools. Although it was still fun  and his is totally fun and awesome, it just teaches people to be complete idiots , like we need more idiots in the world  
it was not a Candlepower fourm informed test, it was the average YouTube clown explosions. people from this forum, arent likly to have battery slime on thier hands (wear gloves), wouldnt be showing a video of thier body parts next to igniting cells, and often even would take a minute or 2 to protect thier equiptment. (equiptment that we gotta wonder if he isnt getting the rest of his information from)

BUT when he Treats US like were the idiots, well that is just the pot calling the kettle grey. 

i saw not only ZERO human safety procedures, but but unlike every statement he uses to defend hisself , he doesnt even KNOW what safety procedures would ever be used.

My BS meter is high enough, but he does have information that totally conflicts with every known battery knowlege in existance. and THAT is most interesting. if it isnt just more BS

http://www.youtube.com/watch?v=dree0rTr1HM
hey watch it yourself, the guy is a clown, clowns are FUN clowns are Great, blowing up stuff is awesome. i LUVE it.
but anyone can see MANY plain as day incorrect safety procedures.
no problem.
but then trashes US , as if were the ones who dont know what is going on. Problem. 

Remember HE is the "PRO" 
then comes back with more BS about a Lab that would use tempered glass ?? LOL hey does it get further OUT than that, without anyone elses BS meter Peaking? 
again calling real pros stupid for doing something Real pros wouldnt EVEN DO, shows that he hasnt seen any real pros even test stuff.


Turns around and said my information is incorrect, which indeed it could very well be, but cant support any of his total BS with a logical comment, or a graph. and sorry every graph out there i worked ferverenally to check shows that i was correct, and i dont know WHERE he is getting his information from. But i would like to see it, because i love new information. and again all i get is BS

he has made claims in this thread, that somehow defends a incorrect (but still functional) charging method, that is not used by any of the better charging devices for li-ion, including the device he owns as shown in the video  make sence of that?

so who is Hedging , and diverting? am i gonna toss out a resistance formula from school, which does not apply to wow you, no.
because the POWER in was the same, if current and voltage are very similar, HOW in HECK does the resistance have anything to do with the chemicals or the heat. It doesnt, flat out it cant, the power is the same, the power is mostly going to the item. what form of sheer magic takes the same ammount of power going to a resister even (his inappropriate example) and can figure in any way that the heat would be different, it CANT as long as the power is the same can it?
so he got a formula off the web or from school or something, tosses it about as if it reallates IN ANY WAY, to what we were discussing, and nobodys BS meter is peaking again?

but i still want to know , what he is trying to say, in english, could at least be interesting, with all the things he is learning that other way.

i have been Insulted , which i can easily Take, what i cant take is being insulted with BS. 
i DIDNT take his clown condescending attitute towards me and US, and only applied all of his own layers of Clowning , to display that he has no right to be insulting the rest of us.
and i dont take well to pushing hard, layers of mis-information.


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## liveforphysics (Apr 10, 2010)

[email protected] vidpro

That's the "highlights video" of lithium battery tests. For the folks who don't give a damn about batteries but who enjoy watching explosions. 


Each of the videos those clips came from was a test video, with test procedure and setup. Only about 1 out of 10 tests had something exciting enough to add into the highlights video. 


There are many videos designed to be educational (though way boreing to watch, yet least they aren't the typical lame stuff.)

http://www.youtube.com/watch?v=8IBapfB0Imo


Am I a safety ninny when I handle batteries? No. When you work with everything on the kila-amp scale for your job, the energy of batteries popping in un-contained outdoor formats simply isn't that scary. 

Hell, it was more scary just setting up the tests next to the guys who were welding and arc/air cutting with a 500amp carbon-arc cutter. 

Until you make a bomb by containing them in a thick aluminum waterproof flashlight, they aren't much different from kiddy fireworks (which aren't scary), and less exciting and dangerous than normal heavy equipment steel working (the shop I used.)


I can't help it if you can't understand how Ri (internal resistance) * I^2 is the direct indicator of the heating in a cell. The member "Silverfox" here is a damn sharp guy (I've got loads of respect for him), he can help explain the relationship between cell internal resistance and heat. I'm not your teacher (and thank God, cause I'm a sh*tty teacher, and you would make an awful pupil because you all ready know everything there is to know.) 

-Luke


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## mdocod (Apr 10, 2010)

Luke,

I want to personally thank you for quite literally tolerating an interrogation pertaining to your various testing and work with lithium chemistry cells. 

The argument has been made, but with no evidence to back it up for years that perhaps there is absolutely nothing wrong with a CC only charge provided there is proper termination. Your argument before about the fact that the separator materials in a li-ion cell could technically handle about 10X the voltage that these cells operate at suggests a lot of leeway for charging voltage. I see that you have been using a CC w/V-testing method for a long time and have no evidence to think that there is anything wrong with it.

I don't see any reason for anyone to be upset about the various tests that you carry out for work related purposes. It's obvious that this is your specialty so anything we can learn from you hear will forever echo the chambers of CPF and bring us up to a better level of understanding of the stuff we are using every day. 

I haven't had a chance to search the internet yet for any cycle life data as it relates to charge methods of these cells. I still think it's worth seeking out, so I will do that when I have a chance. 

Thank You and Regards,
Eric


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## VidPro (Apr 10, 2010)

liveforphysics said:


> Am I a safety ninny when I handle batteries? No. -Luke


 
indeed, it is just here at the CPF we got the oppertunity to read numerous posts about the chemical dangers, and especially a big to-do about the chemicals when they are burning, and some sort of very long term damage that can occur to humans. 

it would read something like this 

http://webcache.googleusercontent.c...+hazards&cd=13&hl=en&ct=clnk&gl=us&lr=lang_en

exerpts
*Strong mineral acids, alkali solutions, strong oxidising materials and conductive materials Lithium hexafluorophosphate may react with water in the atmosphere and produce toxic materials including fluorhydric acid. Thermal decomposition of the cells may produce of noxious or toxic fumes . . .. Hazardous decomposition Products 11. Toxicological Information Signs & symptoms Inhalation None, unless battery ruptures. In the event of exposure to internal contents, corrosive fumes will be very irritating to skin, eyes and mucous membranes. Overexposure can cause symptoms of non-fibrotic lung injury and membrane irritation. Contents of an opened cell can cause respiratory system and mucosa irritation. Overexposure to Lithium Nickel Dioxide may cause an allergic reaction. If gas is generated during cell assembly, throat irritation and nauseas may occur. Dimethyl carbonate (within the electrolyte) may be hazardous to loins. Lung irritant. . . *

and then people around here were a little more carefull and aware of the human exposure thing. A few people had exposures that they went straight to the hospital for.
those were the days, when Newbie would write serious 3000 word essays on safety, and huge posts analising the chemicals and chemicals formed during a thermal runaway.

https://www.candlepowerforums.com/threads/141137&highlight=hydrofloric+acid
*Hydrofluoric acid will, with a possible delayed effect, affect the nervous system, respiratory tract, lungs, and impair the cardiovascular system. Those effects are from inhalation only, more severe effects including weakening of the bones and a host of other things if ingested or from wounds such as LunarModules. i.e. skin contact.*


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## SilverFox (Apr 10, 2010)

Hello Luke and VidPro,

It is nice to see that a nearly civil discussion can be held on "new" concepts...  

Remember we are discussing ideas here, so please leave personalities out of the discussion.

Luke, I agree with VidPro. Your safety policies and examples suck.

I will have more on this later, but have to run now.

Tom


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## SilverFox (Apr 11, 2010)

Hello Luke,

I have been following this thread with interest. All of the liturature I have read tells me that lithium plating begins to occur when Li-Ion cobalt cell voltages exceed 4.2 volts. 

I don't know exactly what is happening inside the cell, but I have confirmed that when you exceed 4.2 volts while charging, the cycle life of the cell is reduced. I have been able to find data supporting this, and have been able to duplicate the testing to verify it for myself. I don't know if plating is causing the reduction in capacity, but there is a degradation going on inside the cell and cycle life is reduced. However, if it is actually plating, this practice could be dangerous.

Looking around at others using Li-Ion cells, I find that the RC people have similar experiences with their Li-Po packs. Great care is put into the hobby chargers that they use in an effort to keep the maximum voltage, at any time during the charge, at 4.200 volts. Some of the chargers exceeded that voltage slightly, and the Li-Po packs charged with those chargers had a tendency to puff. Does plating cause puffing? I don't know, but there is a degradation process taking place. This is a little muddy because there were some issues with the electrolyte in these packs and there are other causes of puffing, but there seems to be a coorelation between overcharging and puffing.

This plating, or perhaps oxidation, also seems to degrade the cells at 4.2 volts so there are studies showing data that reveales you can extend the cycle life by limiting the charge to a lower voltage, like 4.1 - 4.15 volts.

In my mind, this is the current state of the art in Li-Ion care.

You throw out the idea that it is possible to use a faster charge algorithm for faster charging, and by the way, during this fast charge the voltage exceeds 4.2 volts and there is no cell degradation, and there seem to be an implication that this actually provides an increase in cycle life.

This goes contrary to what we have learned so far, however, we are open to new ideas. Li-Ion charging takes a long time and if you have data showing that constant voltage charging has no detramental effects on the cell even when voltages exceed 4.2 volts, we are all eagerly waiting to see it.

In the NiMh chemistry we have 15 minute charging. It works very well, but your cycle life is drastically reduced. I am not sure 15 minute Li-Ion charging can be done, but I would love to be able to charge my cells in 30 minutes. Right now about the best I can do is just under 1.5 hours.

The A123 cells are an exception to this. You can do a zip charge and have them charged up in 6 - 10 minutes and they seem to endure that very well although the data on this only goes out to a couple of thousand charge/discharge cycles.

I don't own a WF-139 charger. What I have seen from the data presented by others that have this charger, I don't think it is a good charger to use. You happen to think that it is a future glimpse of where Li-Ion charging is headed.

While I respect your ideas, where is the data?

If I were going to bring forth an idea like that, I would have comparison data to accomany it. 

Here is test data showing 200 cycles on the WF-139 charger with its "advanced" CC charging method, and here is the data showing 200 cycles using the CC/CV method. I would then point out that the cell charged using the CC method ended up holding a higher voltage under load, and showed less capacity reduction. I would also point out the time savings involved using the CC method.

This is the piece of the puzzle that is missing from this discussion.

Historicly, this has been tried before and the manufacturer changed the charger from a CC rapid charger to a CC/CV charger. The reason for the change was several suites brought against the manufacturer for damages done due to rapidly venting cells, and warranty issues due to rapid cell degradation. This manufacturer has been involved in Li-Ion cells for a long time, and most of us know them as Pila.

I don't think your method works, but if it does, I will dust off my old Pila charger and breathe new life into it.

A note on over voltage. The current UN shipping regulation require cell manufacturers to do testing that includes over voltage conditions. This testing involves charging a cell to 2X its normal voltage. The cell passes the test as long as there is no leakage, no venting, no fire, no flame, and no thermal runaway. However, under these conditions the cell can be irreversibly damaged.

The problem with this test is that it is done once. The manufacturers state that plating can occur at higher voltages, and if you end up at the lower end of that plating voltage (which I believe occurs at just above 4.2 volts) you can plate just a little out. When this is repeated over and over again the cell becomes more unstable and the next time you go to charge it, you may end up with a rapid vent with flame incedent. 

If you are going to subject a cell to over voltage once and then recycle it, fine. It should be able to handle 8.4 volts and not blow up. However, if you then take that cell and cycle it, you may have an incident.

I don't have a lot of experience with Li-Ion technology in electric transportation. I do have discussions with the local University on their experimantal vehicle program, but they tend to prefer the A123 cells over the Li-Ion cobalt cells, so most of my experience is with that chemistry, and that chemistry seems to be very robust.

We can theorize untill the cows come home and still not know what works better. It is time to generate some test data. The expanse of testing that we are capable of will not be conclusive, but at least it has the possibility of focusing our discussion.

Tom


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## 45/70 (Apr 11, 2010)

That's pretty much the way I understand it, Tom.

After thinking about this over the weekend a bit, I seem to remember that the Tesla Roadster's "fast" charge took about 3 1/2-4 hours. This would seem indicate that they are using a CC/CV charge algorithm, or at least not some method that is any faster.

As I too said before, I'm open to new ideas. I think however, for the time being the manufacturer's recommendations should still be followed, at least until more information and data is available.

Dave


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## march.brown (Apr 12, 2010)

As a comparative novice in the field of Li-Ion cells , could someone answer a couple of questions please ?

Does this "plating" on a Li-Ion cell reduce the capacity in the same way that Sulphating does on a Lead-Acid cell ? ... Reduction in surface area ?

Why does the plating cause the Li-Ion cell to become unstable ? ... Does the plating produce an internal "counter-EMF" Li-Ion cell which then has the current forced through it in the wrong direction ? ... This would give the same effect as a multi-cell torch with cells in very different states of charge.

What percentage of Li-Ion cells used in flashlights actually vent or explode ? ... We can then calculate the approximate odds against experiencing a dangerous cell incident ... We tend to hear about the ones that explode or vent but not about the large number that don't give any problems ... After all , nobody goes to the Doctor to tell him that they are feeling well !
.


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## Font size (Apr 12, 2010)

Question authority!


45/70 said:


> I think however, for the time being the manufacturer's recommendations should still be followed,


 Think for yourself!

[FONT=&quot]I took my car in under warranty. The manufacturer General Motors said it was only covered if driven within the legal limits. Which were 55mph at the time. “Unsafe at any speed,” has been common knowledge for many decades. There is a conflict of interest in manufacturers recommendations. You must think for yourself. Now my cars are built in Germany.[/FONT]


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## SilverFox (Apr 12, 2010)

Hello March.brown,

Plating involves a change from lithium ions to lithium metal. Lithium metal in a cell is unstable and greatly increases the risk of thermal runaway.

Early Li-Ion cells were made with lithium metal and there were frequent fire incidents.

The loss of lithium ions will reduce the capacity of the cell, but it is not quite the same as sulphation in lead acid.

The number of people that use Li-Ion cells outside of a totally engineered battery pack is quite small, and we have pushed safety and education very hard. The fact that I know at least a couple hundred people that have never had an automobile accident doesn't necessarily mean that it is safe to drive.

Tom


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## 45/70 (Apr 12, 2010)

march.brown said:


> Why does the plating cause the Li-Ion cell to become unstable ? ...



Hi march. Metallic lithium is not part of the chemical makeup of Li-Ion cells (only lithium ions), ie. it is not supposed to be present within in the cell. When it is formed, under improper usage conditions, there are chemical components that exist in the cell that can cause the metallic lithium to oxidize rapidly ("vent with flame").

From BU,



> [FONT=Verdana, Arial, Helvetica, sans-serif]What happens if a battery is inadvertently overcharged? lithium-ion is designed to operate safely within their normal operating voltage but become unstable if charged to higher voltages. When charging above 4.30V, the cell causes plating of metallic lithium on the anode; the  cathode material becomes an oxidizing agent, loses stability and releases oxygen. Overcharging causes the cell to heat up. If left unattended, the cell could vent with flame.[/FONT]





Font size said:


> Question authority!...... Think for yourself!



Hi Font. If you had quoted my entire sentence, 



45/70 said:


> I think however, for the time being the manufacturer's recommendations should still be followed, at least until more information and data is available.



it would have been more apparent that I am! 

Dave


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## Curious_character (Apr 12, 2010)

march.brown said:


> . . .What percentage of Li-Ion cells used in flashlights actually vent or explode ? ... We can then calculate the approximate odds against experiencing a dangerous cell incident ... We tend to hear about the ones that explode or vent but not about the large number that don't give any problems ... After all , nobody goes to the Doctor to tell him that they are feeling well !
> .


Let me be the first. I turned on my flashlight today and it didn't explode.

I also drove my car and flew my airplane and didn't crash.

And I'm feeling well.

c_c


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## march.brown (Apr 12, 2010)

Curious_character said:


> Let me be the first. I turned on my flashlight today and it didn't explode.
> 
> I also drove my car and flew my airplane and didn't crash.
> 
> ...


 
But now you're waiting for something bad to happen aren't you ?

p.s. The Auster Autocrat that I was learning in (many years ago) made a forced landing ... Actually it had an engine failure and crashed ... It was a total write-off ... It was upside down and I made a tactical error ... In my haste to get out , I pulled the pin out of the harness and being upside down I fell headfirst onto the trim controls ... Luckily I only had head and lower leg injuries , but that was in 1971 and I'm alright now.

Don't ask about motorbike , car rallying and swimming accidents plus Army service though.

At the age of 72 and with all these minor problems , I am not going to let a little battery beat me.
.


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## mdocod (Apr 12, 2010)

Hello Tom,

I want to thank you for very effectively articulating where you believe the current stance on Li-Ion cells is. I have been hoping for someone to come forth with some actual experience _or_ evidence we can point to.

Not sure if you've had a chance (or others reading this) to see the recent updates to the li-ion cradle charger roundup thread, but there are now about 10 chargers in there all tested. At this time, only 1 of them charges correctly based on manufacture recommended charging practice and that is the IBC. Most of them either trickle in some way, or over-shoot 4.20V during charging, or both. 

-------------

CPF has acknowledged Tom as being likely the most widely versed expert on batteries for many years. If he has read those studies and articles and dug up evidence to suggest that a CC method is less safe or can reduce cycle life, then at this time, I think it would be safe to continue to treat the CC-only method as less than ideal. 

-------------

Luke, 

As I had suggested/requested, and now Tom, if you could provide a cycle life study and/or cell health study comparing the effects of charging methods, that would be much appreciated. 

-------------

Eric


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## Font size (Apr 13, 2010)

*Re: Running tests on the WF-139*

Mdocod you keep telling us that the Pilas charges differently than the WF-139.


mdocod said:


> Only one of them charges correctly ... and that is the IBC. Most of them either trickle in some way, or over-shoot 4.20V during charging, or both.


Am I to understand that you are saying that all the chargers except the Pila that you love, do not go over 4.20v during the charging cycle. In spite of the recent post that shows that it does?


Meterman said:


> Above *.. *a Pila charging a 14500 you see the voltage rise to 4.227V during the CC phase..


Metermans post shows the Pila charging above your figure during charging.


liveforphysics said:


> As flashlight battery charger design catches up, you will see all chargers charge like the WF-139.


Another recent post claims that it does not matter when you over-shoot 4.20V during charging phase.


mdocod said:


> Most of them either trickle in some way..


I thought we understood that the older versions of both the Pila and the WF-139 may have trickle charged, but modern versions of neither charger do now?

So, how can you keep advertising that the Pila alone does not trickle, and that it is important to you that a charger does not over shoot, when the Pila clearly does, using a less advanced charging algorithm?.


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## mdocod (Apr 13, 2010)

*Re: Running tests on the WF-139*

Hello Font Size,

First of all, yes, the IC that the Pila IBC uses as it's "brains" has the ability to over-shoot the final termination voltage by a small margin during charging in order to help speed up the CV stage of the charge while still staying inside li-ion cell manufacture safety guidelines for charging. The amount of over-shoot is determined by a sense resistor selected by the builder of the charger and is effected by the resistance of the cell being charged. Pila has chosen to use what would be a very very mild overshoot (to about 4.21V on larger cells) when charging the cells that the charger is specified for use with. (17500-18650 size)

The chart you have quoted, says that the test was done with a 14500 size cell, which is not a cell size that Pila has listed under compatibility, so the mildly modified over-shoot that you are seeing in the chart is being exaggerated by the fact that the 14500 size cell has a higher resistance than a 17500 or larger size cell. Regardless, the chart posted does not show the Pila IBC doing anything wrong, in fact, in reinforces that even on a small cell, the Pila IBC is STILL charging safely and correctly.

The chart that has just been posted shows both a maximum charging voltage AND termination voltage that are BOTH well within manufacture guidelines for charging. When myself or anyone else is talking about "proper" termination what we are looking for is 4.20V+/-0.05V or 4.15-4.25V. You may find that my posts are often very long winded already, I find myself making best efforts to reduce the length wherever possible and have been saying just "4.20V" and leaving out the +/-0.05V qualifier in many of my posts. I see now that I can no longer get away with this and will make a best effort to be as long winded as necessary to prevent any future misunderstandings. 

Consider the following:
If manufacture suggested charging method is CC/CV with maximum recommended voltage of 4.25V followed by a true termination (no trickle), then provided that at no time during the charge voltage rises above 4.25V, and provided that there is a true termination, then we are following manufacture recommendations for proper charging of the cell. 

The first generation WF-139 will bring small cells as high as 4.4V (usually cutoff at 4.35V by a PCB), medium size cells will see charging voltages of around 4.3V, and larger cells will still see charging voltages in excess of 4.25V. Later model 139s ramp down the charging rate slightly towards the end of the charge but are still going to achieve charging voltage in excess of 4.25V on almost all cells. 

The original Pila that trickle charged was not the "IBC" model. So anytime we are specifically talking about a Pila that uses CC/CV or talking about the IBC, you can assume we are talking about the IBC that does not trickle and uses proper CC/CV charging.

At this time, we have more evidence to suggest that charging voltage in excess of 4.25V is probably worse for cells than we do the other way around. Until a study is posted comparing cycle life for different charging methods the recomendation to stay within manufacture guidelines for charging will stand in my recommendations. 

Eric


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## SilverFox (Apr 13, 2010)

*Re: Running tests on the WF-139*

Hello Font size,

Your comments are a little hard to understand. Perhaps you could answer some questions so that I can better understand what you are trying to say.

What do you think is the difference between CC charging and CC/CV charging?

Which method is recommended for Li-Ion charging by the battery manufacturers?

Have you ever reviewed a data sheet that gives the proper charging voltage for Li-Ion cells, and also gives a tolerance value? What is the tolerance value listed?

How do you tell the difference between the early WF-139 charger, and the most recent WF-139 charger?

How do you tell the difference between the Pila charger and the Pila IBC charger?

If you can provide answers to these questions I think we can all get on the same page with this discussion.

In addition, if you happen to have it, I would be interested in the capacity retention of a cell after 100 charge/discharge cycles using the WF-139 and have that compared to 100 charge/discharge cycles using the Pila IBC. I know you don't have this comparison, but it would go a long way in illustrating the differences.

Tom


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## SilverFox (Apr 13, 2010)

*Re: Running tests on the WF-139*

Hello Eric,

While Li-Ion manufacturers list the charging tolerance as + or - 0.05 volts, Li-Po manufactures have discovered that the additional 0.05 volts can cause puffing of the cell. They tightened the specification to 4.2 volts + 0.00 or - 0.05 volts.

Since the mild degradation that causes puffing is not noticible in a round cell that is in a can, we don't know what that extra 0.05 volts actually does.

We all know that you will get better performance if you limit the charge voltage of the cell, so I think the Li-Po specification is better.

Tom


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## Tohuwabohu (Apr 13, 2010)

*Re: Running tests on the WF-139*



mdocod said:


> Hello Font Size,
> 
> First of all, yes, the IC that the Pila IBC uses as it's "brains" has the ability to over-shoot the final termination voltage by a small margin during charging in order to help speed up the CV stage of the charge while still staying inside li-ion cell manufacture safety guidelines for charging. The amount of over-shoot is determined by a sense resistor selected by the builder of the charger and is effected by the resistance of the cell being charged. Pila has chosen to use what would be a very very mild overshoot (to about 4.21V on larger cells) when charging the cells that the charger is specified for use with. (17500-18650 size)
> 
> The chart you have quoted, says that the test was done with a 14500 size cell, which is not a cell size that Pila has listed under compatibility, so the mildly modified over-shoot that you are seeing in the chart is being exaggerated by the fact that the 14500 size cell has a higher resistance than a 17500 or larger size cell. Regardless, the chart posted does not show the Pila IBC doing anything wrong, in fact, in reinforces that even on a small cell, the Pila IBC is STILL charging safely and correctly.



The voltage at the end of the CC stage will be the same independent of the cell size. A 18650 only will charge slower because of its higher capacity.
The height of peak is not determined by battery resistance but by the neagtive output resistance of the charger.

Here is a graph of my Pila IBC charging a protected red and black Trustfire 2400mAh 18650 that I had discharged to 3.2V resting voltage:





The last hour of the the graph above:





The Pila IBC is designed for protected batteries.
At the end of the CC stage the voltage measured at the battery contacts is 4.232V but the voltage at the cell itself is lower because of the voltage drop across the protection curcuit in the battery. The charging current at that point is 635mA. Assuming a protection curcuit resistance of 50 milliohms that would result in a voltage drop of 0.635A * 0.05 Ohm = 32 mV and a voltage at the Li-Ion cell of 4.20V.
During the CV stage the voltage at the battery contacts slowly drops to 4.213v as the charging current goes down to 70mA but the voltage across the cell actually rises at the same time to 4.213V - 0.050 Ohm * 0.07A = 4.21V.


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## Font size (Apr 13, 2010)

*Bench Mark*

Sure I will give it a try if you think it will be of help to people to have all of this information in one place.


SilverFox said:


> What do you think is the difference between CC charging and CC/CV charging?




The charge cycle is broken up into three phases, a fast charge constant-current (CC) phase, .. 
a reduced rate constant-voltage (CV) phase, 
and then it turns off.

The maximum charge rate is limited because the cell life decreases with higher charge rates. 


In phase II, the charger maintains a constant voltage because a lower final voltage will result in reduced capacity, and an over-voltage will reduce cell life and can pose a safety hazard. 
In phase III, the charge current reduces until it reaches a minimum, then it turns off.



*In summery at first you have a constant current, then later you have a constant voltage, and then you have none.*
​ Charging Requirement for Rechargeable Li-ion Batteries


> Which method is recommended for Li-Ion charging by the battery manufacturers?


The closest I can get to the manufacturer as a consumer is my supplier. AW tells us the WF-139 and the Pila have the correct charging method for the cells that he supplies to customers.


liveforphysics said:


> It's a little more costly to setup, requires u-Controllers and programming rather than a simple analog circuit, but the advantages make it worth the extra trouble for any time-critical charge applications.


 Liveforphysics tells that the WF-139 has evolved beyond a simple CC/CV method.


mdocod said:


> The test was done with a 14500 size cell, which is not a cell size that Pila has listed under compatibility.


After seeing Pila recommended as the Gods on solution to cell charging of every size.


45/70 said:


> the manufacturer's recommendations should still be followed.


 And recommendations to blindly follow corporate rules of all sorts. Now I see the Pila does not list the most common AA cell size under compatibility for its charger.


Hitthespot said:


> Pila IBC Charger Review~I would not recommend charging "any" battery rated below 600mah.


*So, we have people saying follow manufactures recommendations, then you have the charger company telling you they do not recommend that you charge AA Cells with a Pila. We have the cell maker, telling us the WF-139 is OK. We have a scientist tell us the WF-139 is advanced. Then you have the guys shouting fire in a theater that the WF-139 is unsafe and that we should follow manufactures guidelines, instead of thinking for ourselves! *


SilverFox said:


> Someday, their marketing department may talk to the engineering department and get it right...


People should think for themselves and question authority. European cars had anti-lock brakes years before American corporate lawyers would let US companies use the new technology. Now everybody uses it, or was that air bags?


> Have you ever reviewed a data sheet that gives the proper charging voltage for Li-Ion cells, and also gives a tolerance value?


No, I leave that up to the guy who has protection circuits built into his cells.


> What is the tolerance value listed?


 AW tells us +/- 0.05V


AW said:


> "WF-139 is OK (newer version that terminates at 4.2V +/- 0.05V). I have done testing with over 50 pcs. of them and none of them charges above 4.25V."


AW says the WF-139 does not go above 4.25V in his testing.


SilverFox said:


> I would prefer that it was 4.2 volts plus 0.000 minus 0.05 volts.


What can you do?


> How do you tell the difference between the early WF-139 charger, and the most recent WF-139 charger?


If you have been using the same charger for five years and still using the same cells as when you bought it. You are probably in danger. Most likely you do not have the latest version.


GrAndAG said:


> It's easy to distinguish which version of WF-139 you have without disassembling...
> 1st revision has ~10V open circuit, blinks while charging (CC/CV method)
> 2nd revision has ~5V open circuit, blinks while charging (CC/CV method)
> 3rd revision has ~4.3V open circuit, lights red while charging (lowering current method).
> It has labels printed using white paint, not silver as two previous.


The biggest mistake WF-139 advertisers made, was not changing the name when they changed the design.
If I were selling the newer versions I would put a paint stripe on it and call it a Shelby or something.
It is hard to image anyone buying a new charger today that will get one five years, and three technologies out of date.


> How do you tell the difference between the Pila charger and the Pila IBC charger?




This picture shows that you can read IBC on the bottom.


> I would be interested in the capacity retention of a cell after 100 charge/discharge cycles using the WF-139 and have that compared to 100 charge/discharge cycles using the Pila IBC.


I saw that when you posted this before.


SilverFox said:


> ..test data showing 200 cycles on the WF-139 charger with its "advanced" CC charging method, and .. the data showing 200 cycles using the CC/CV method.


Yes a test like that will reveal loads of information.
It just goes to show that people should think for themselves and question authority.


mdocod said:


> ..only recommended method for charging.


 My Dad was using Radial tires on his cars many years (about ten years), before manufactures recommended using radials on US cars. Common sense, is not common. 

The trend in lights is *brighter, smaller, and cheaper.* The time to make a Li-Ion charger selection is not after you have $200.00 worth of lights in which case a Pila would cost 25% of your light costs. But you must choose your first Li-Ion charger when you decide on what cells you are going to use in your first high tech light. Today’s entry lights as I see it, glow around 100 lumens. These new lights are so inexpensive that a charger that costs 50% of the cost of the light is way more reasonable to a new buyer, than a charger that costs 150% more than the cost of the customers first torch.


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## dfischer (Apr 13, 2010)

I come, I go. sometimes i linger, sometimes not.

I soon learn some are learned, some are gentlemen. A select few are widely respected for being both.

Others, in time earn respect by asking thoughtful questions, or by offering thoughtfull insights. And of course good manners are expected.

The masses come, learn a bit, and go, politely and respectully. Usually acting like a guest in someones home.

Then there are the trolls and the flamers. Rare here, and really not welcome, but even then treated with respect.

I know which I am, which I am not, and what I hope to never be. 

Perhaps sir, you should ask yourself the same questions.


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## SilverFox (Apr 14, 2010)

Hello Font size,

Thanks for taking the time to put that together.

It looks like you understand most of the basics.

The basics include:

CC/CV charging,
Keeping the cells voltage at 4.2 volts, plus or minus 0.05 volts,
shutting off at the end of the charge,
and managing the heat build up in the cell while charging.

Sanyo, Sony, Panasonic, LG, Samsung, GP, and the other leading battery manufacturers state that if you follow the basics, the cells should be safe to use and give a decent cycle life.

Issues begin to arise when you deviate from the basics.

Hobby chargers have been correctly charging Li-Ion cells since they came out. Most of the hobby chargers follow the basics, but there are some that overcharge. ThunderPower issued a warning that their Li-Po packs would puff if the voltage ended up above 4.000 volts. They had many returns and did a lot of research to determine this. Li-Ion cells don't puff, but they have the same chemicals as Li-Po cells do. That is why I prefer a charger that clamps the voltage at 4.200 volts maximum.

Your graph does a good job of illustrating the difference between charging to 4.25 volts and charging to 4.00 volts. My own testing confirms that trend, however, some cells take a more drastic hit than others. That part of charging has been well studied and there is a lot of data that demonstrates the principle that when the voltage exceeds 4.2 volts, the cell degrades faster than it would in normal use.

Luke comes along and speculates that a different charging method is faster, but doesn't provide any data backing up his claim, or any data showing the effects on cell performance. The main issue with rapid charging is taking care of heat. EV packs incorporate a cooling system for the battery packs, try to minimize the charging times, and still have battery packs fail on them. I am all for extending the technology, but feel a need to review the test data before jumping on board.

You are absolutely correct. The battery manufacturers give the basics on how to charge and tell you to follow them. Every pack or cell has a little different requirement, so you would end up with a charger for every type of cell.  Also, the Pila IBC charger is recommended for Pila cells only.

You can meet the manufacturers basics by using a hobby charger, but the quality hobby chargers are more expensive than the Pila IBC. As you have noticed, cost is a deciding factor for a lot of people. This brings us to the WF-139. I am glad that AW was able to influence the people who make the WF-139 to get their ending voltage more in line with the "basics," but there still seems to be a lot of variability with these chargers. If you get one that works within the boundaries, great, but I don't think you can make a general recommendation that they are a good charger regardless of where they are purchased.

The reason the Pila IBC is often recommended is that it is consistent in performance from charger to charger. It also follows the basics of charging Li-Ion cells. It's downfall is that it only charges at one current rate. It does cost more, but the quality difference justifies the cost. In this case you get what you pay for.

If you look at the example Meterman provided you will see that while 4.2 volts was slightly exceeded, it didn't come close to 4.25 volts. My Pila IBC charger also exceeds 4.2 volts. I have measured all the way up to 4.21 volts. However, it doesn't stay there long and my prime cells come off at 4.20 - 4.19 volts. For an inexpensive charger, I think that is pretty good.

You bring up AA sized Li-Ion cells. This is a very small niche size in Li-Ion chemistry. I am not aware of any appliance that uses that size, and it looks like it is limited to specialty flashlights. When you can find those cells in your local hardware stores, you will also find a charger to use with them. If you have a hobby charger you can probably properly charge them, but if you don't you will have to take things into your own hand and hope for the best. In this case, I would still recommend the Pila IBC charger over anything else, except for a good hobby charger.

The bottom line is that people want an inexpensive product that is simple to use. They are unwilling to learn the basics and put the effort in to learn how to operate a more complex piece of equipment. I think everyone should start with a hobby charger, and if they decide to go on from there, they can then make a much better informed choice of what their next charger should be. 

The EV efforts have been interesting to follow. These battery packs are so expensive that cycle life is the top priority. They do take liberties with the basics, but engineer in controls to keep things in line. Charging to 4.1 volts drastically increases cycle life, and allows for some extra headroom should you suddenly need it as in the case of regerative breaking. 

I recommend the Schulze line of chargers. The Pila IBC will do in a pinch...

Tom


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## liveforphysics (Apr 14, 2010)

SilverFox said:


> Hello Font size,
> 
> Thanks for taking the time to put that together.
> 
> ...


 

I visit bellingham every few months (I live a little south of Seattle.) I've been a fan of your battery testing work for years Tom. If you would like to try out an EV bike or motorcycle sometime, we should meet.  
 
-Luke


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## SilverFox (Apr 14, 2010)

Hello Luke,

I am aware of the high humidity problem, but the problem still continued afterward. By the time they addressed the humidity problem, the RC crowd had tuned into the problems with higher voltages and took measures to limit the charge voltage below 4.200 volts.

Yes I can question that it is faster... However, to prove this a test would have to be done. The test would involve measuring the capacity of cells charged to 4.2 volts, then subjecting them to being charged on the WF-139 and the Pila IBC. In a side by side test I think the Pila IBC would be faster.

In addition, if 50 charge/discharge cycles were run and at the end of this testing the capacity and voltage retention under load were measured, I would guess that the cells charged in the Pila IBC charger would show less degradation and higher voltage under load.

I don't own a WF-139 charger, and have no desire to have one in my house, or I would run the test myself.

Heating cells before charging has been done since there has been Li-Ion cells. If you don't warm them up to at least room temperature, the lithium plates out and makes the cells unstable. Also, the state of charge voltage varies with temperature. Saft has done a lot of work on this in regard to using Li-Ion cells in space. It's pretty cold out there.

Heating of the cells that we are using is usually done by the charger electronics. The Pila IBC charger has a lid that allows you to charge with the lid open for cooler operation, or you can close the lid and the cells will warm up a little more. I haven't measured the exact temperature of the cells, but they feel like they are at about 90 - 95 F.

You are correct. Electrons are not brand specific. However, what is specific is the optimum charge rate you should use. If you have a 2400 mAh cell and want to charge at 0.7C, you want the charger to charge at 1680 mA. With a 600 mAh cell, the same 0.7C charge rate would be 420 mA. 

The hobby chargers allow you to set the charge rate. Neither the WF-139 or the Pila IBC do. 

My cells must be in much better shape than your cells... You should trade your "crap" cells in for some good ones...  When I start with a cell that is in excellent shape and use a power supply set to 4.200 volts to charge it, I end up with a cell with a resting voltage of 4.200 volts. Sometimes it comes in at 4.199 or 4.198 volts so that is a little under 4.2 volts, before rounding.

After I run the heck out of the cells, they degrade and will no longer end up at that voltage. As the degradation continues, the voltage at the end of the charge to 4.2 volts drops lower and lower. I have run some informal tests on raising the charge voltage in order to get the degraded cells to end up at 4.2 volts, but this has always ended up with an increase rate of degradation. At this point I become concerned with plating so I just crank the voltage back down and live with the reduced capacity of the cell.

I disagree with you. The moms that I know that have an interest in charging Li-Ion cells have a lot more common sense that most of us. They call with questions and watch the process with the intent and skills they learned watching children. The moms that don't give a crap about what powers the light, but have a need for a light, are very happy to go down to the store and pick up a AA light and a pack of Alkaline batteries. Their attitude is that brighter lights are cool, but all they need is a little light to see something and if you have to jump through hoops to get the battery charged for the bright light, they settle for a little less light and the ease of using Alkaline batteries.

You do bring up a good point though. The hobby chargers allow for bigger mistakes to happen.

I should point out that all this discussion is pointless if we are using the A123 cells. The basic limits are much looser on those cells, and a failure incident usually only involves a loud pop.

I am in Seattle frequently. We will have to try to hook up.

Tom


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## VidPro (Apr 14, 2010)

Great pics there.

what you got in the thermal pic, is some really wild situation.
are you first wondering why they are trying to apply such a high charge rate ?
then why the cell item in the pic has such poor distibution of the energy?

then is this cell item a gelled type electrolyte? And isnt it a high amp charge capable cell item? so why is it not really a high amp charge capable cell item? that is weird, and probably par for some stuff.

Do you have any info on what is the cell, what is the capacity, what it is the rate , or anything? because without that info it just looks like Everything is all Wrong about it? What manufacture rated THAT cell item for that kind of charge rate?


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## liveforphysics (Apr 15, 2010)

VidPro said:


> Great pics there.
> 
> what you got in the thermal pic, is some really wild situation.
> are you first wondering why they are trying to apply such a high charge rate ?
> ...


 

The cells in the thermal test pictures are A123 15Ah prismatic lithium iron phosphate polymer cells. These are the highest energy density LiFePO4 cells in the world right now. I've got a stack of the 15Ah and 20Ah versions. 

They are pretty impressive. These two stacks are both 80Ah of LiFePO4, and look how much less space the prismatics take up.


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## VidPro (Apr 15, 2010)

too cool. 
i am still hedging on trying the flat li-fe things. just because the li-poly things are lighter, for the same watts.

if you weighed similar "watthour" capacity of li-poly vrses li-fe flat bagged packs, what is the Real weight differance?
or of the same weight what is the actual watthour differance?
not the I/O Rate, because i dont usually use extreeme rate, but how much power for weight?


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## liveforphysics (Apr 15, 2010)

VidPro said:


> too cool.
> i am still hedging on trying the flat li-fe things. just because the li-poly things are lighter, for the same watts.
> 
> if you weighed similar "watthour" capacity of li-poly vrses li-fe flat bagged packs, what is the Real weight differance?
> ...


 
To get perspective on LiCo lipoly vs LiFePO4 lipoly, I took a few pics.
Here is 112whrs of A123 LiFePO4 LiPo(1 x 15Ah cell, and 1 x 20Ah cell) and 115whrs of LiCo LiPo together for a size reference. They are actually very close in terms of volume, and roughly identical in terms of power and energy. Both are safe for 5C/10C charging. 

The LiCo Lipo has the volume advantage by 22%, and perhaps a %5 weight advantage, but it's not a fair measurement, as the LiCo cells are assembled into a pack with leads/shrink/connectors etc. 

BTW- These Turnigy LiPo cells have been crazy good. For energy storage critical events, we charge to 4.45-4.50v/cell, and get >7Ah of useable capacity out of a 5Ah cell. LiFePO4 always self-discharges back to 3.6-3.7v when we try those tricks. Just using a 4.25 HVC to 3.3v LVC, we always get well over the rated capacity, often 5.5Ah is average. Even under continous 20C discharge they stay cool as can be.


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## jirik_cz (Apr 15, 2010)

liveforphysics said:


> BTW- These Turnigy LiPo cells have been crazy good. For energy storage critical events, we charge to 4.45-4.50v/cell, and get >7Ah of useable capacity out of a 5Ah cell.



That sounds really crazy oo:
How much cycles they can make under these conditions?


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## liveforphysics (Apr 15, 2010)

jirik_cz said:


> That sounds really crazy oo:
> How much cycles they can make under these conditions?


 

Ehh, in my RC heli's, I've got packs with a couple hundred cycles of 4.5v/cell, and the packs still perform like new. 

For these EV race applications, the number of cycles isn't really a factor when you've got less than race 10 events for the whole year, and you can charge to 4.125v/cell for all the practice sessions and tuning etc. 

We tested 15 of the 30C Turnigy 5Ah LiPo cells indivdually bringing them all to 5v/cell SOC. None got warm. None puffed. None showed any signs of problems at all, and they all discharged a huge amount of additional capacity (duh). This was when we felt it would be OK to try a much more conservative 4.5V/cell in the 8kw-hr race packs, which made them into >10kw-hr packs!  

1st and 2nd gen LiPo formulas would have exploded from this type of treatment. These 3rd gen formulas are crazy stable! Still, I firmly do NOT recomend you try this sort of thing unless you have an application where the extra capacity is worth the risk of burning your pack/vehicle into ash, and if you're charging in an area that is safe to handle a huge LiPo venting event. 

The cells do say right on them something like, "4.35v full, 3.2v empty." All my earlier LiPo cells would say "4.25v full".


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## ampdude (Apr 15, 2010)

I wonder about the possibility of the WF-139 overcharging RCR sized batteries, only because the IMR16340 cells don't seem to overcharge on either my older or newer style WF-139.

The highest I ever get is 4.23 volts fresh off the charger. Usually they end up around 4.21v after a near full discharge and recharging cycle. And the IMR cells of course don't have any type of protection circuit.


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## 45/70 (Apr 15, 2010)

Again, interesting stuff there, live.



liveforphysics said:


> Ehh, in my RC heli's, I've got packs with a couple hundred cycles of 4.5v/cell, and the packs still perform like new.



For clarification, which chemistry are you using in the heli's? I'm also asuming (yeah, I know, uh oh) these are partial cycles, as opposed to actual full cycles, correct? I don't imagine you fly heli's until the batteries quit, then again..... 



> For these EV race applications, the number of cycles isn't really a factor when you've got less than race 10 events for the whole year, and you can charge to 4.125v/cell for all the practice sessions and tuning etc.


So for racing you charge to the higher voltages, and for practice/putting around to 4.125 Volts, is this correct? Also, are these just the LiPo and LiFe packs, or does this also include LiCo packs composed of cylindrical cells, similar to what we use in flashlights?

Thanks live. Just trying to better understand your specific applications. 

Dave


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## liveforphysics (Apr 15, 2010)

My heli (T-rex 600E) runs 3rd generation 30C/50C LiCoO2 Lithium Polymer cells. I've tried 4.5v on the 1st gen lipo, it blows up. 4.5v on 2nd gen LiPo puffs and the cell has useless Ri. The 3rd gen formula just seems like it rough.  These 3rd gen cells are the same cells we run in the TTGPX race bikes. 

Last years winner used Lithium polymer LiMnO2 cells, which are actually extremely safe, and the factory (Kokam) claims you can over-volt them to 20v/cell with no venting (but the cell is wrecked). They also claim better puncture and venting safety than the A123 LiFePO4 cells. In GM's battery type testing for the Volt project, their testing put LiMnO2 above A123 LiFePO4 cells in safety performance (a big part of why they picked the LiMnO2 LG cells over A123). 

We use LiCoO2 because it has about 30% better energy density, and lower capacity specific internal resistance than LiMnO2 polymer, though LiMnO2 is supposed to be some of the most safe out there. 

In the light EV world, we do use a cell you commonly use in flashlights. The Kinion 18650. We normally run them 24S and at least 12-20P for each cell group. They have quite a following because they have a crazy "self balance" effect that eliminates the need for a balance-type charger and/or balance BMS. The cells work great! Just a PITA with the amount of time it takes to assemble since each cell holds just a tiny amount of energy.


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## JaguarDave-in-Oz (Apr 15, 2010)

Gentlemen, if I may drag you all back to the Wf-139 for a moment or two please?

I have a wf-139. It's the later version that holds about 4.80 volts across the contacts when there's no battery on board.

I look at the graph capacity/no-of-cycles pictured in post #160. I use a whole bunch of AW 17670 protected cells in my 2x123 size torches and find myself recharging any one cell about every three weeks (let's say 20 times a year).

Given that I have a cell life expectation of three to four years for my battery rotation stock - if that graph is accurate then for me it would look like charging on the red line 4.25V or the blue line 4.3V would be the best for me from a stored power versus number of cycles point of view for my particular usage pattern.

Where does my current wf-139 fall in relation to those red and blue lines?


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## Font size (Apr 15, 2010)

*Re: Running tests*

Subject to what you may soon hear from the experts on this matter.


JaguarDave-in-Oz said:


> Where does my current wf-139 fall in relation to those red and blue lines?


Your charger should be the black line. Some posters will claim that it may safely fluctuate between the black and the red lines. The guys shouting fire tell us (no shown facts), that the blue and green lines will explode and burn down your house.




The other factor is these cycle tests should not be done with a full discharge, this is not how people use flashlights. The cells will last longer and get better results if topped up instead of being fully discharged.


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## SilverFox (Apr 16, 2010)

*Re: Running tests*

Hello JaguarDave-in-Oz,

When you take a new cell and charge it on your charger, and leave it after it is full for about 24 hours, what voltage does the cell end up at?

Used cells will end up at a lower voltage, so it is best to use a new cell for this test.

Remember this is a test and not a recommendation for normal charging.

Next you need to look up the data sheet for your cells. If the data sheet calls a full charge at 4.2 volts, you should charge to 4.2 volts. There are some new cells that are rated at 4.35 volts. If you have those cells, you have a little more leeway in charging.

When you overcharge a cell that is designed to be charged to 4.2 volts, you run the risk of oxidizing the electrolyte, damaging the electrodes, and damaging the separator. Depending on how the charge tapers off, you can also plate lithium metal out of the lithium ions. When you end up with lithium metal in the cell, the cell becomes unstable. This unstable cell can rapidly vent (sometimes with flame) during charging, or under heavy discharge. Occasionally, they also have problems during storage, especially if heat is involved.

No one knows how many cycles it takes to plate lithium metal out. We simply take the position that it is safer if you don't go there.

Let us know what your test results reveal.

Tom


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## Font size (Apr 16, 2010)

*Re: Running tests with WF*

Private


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## VidPro (Apr 16, 2010)

liveforphysics said:


> To get perspective on LiCo lipoly vs LiFePO4 lipoly, I took a few pics.
> Here is 112whrs of A123 LiFePO4 LiPo(1 x 15Ah cell, and 1 x 20Ah cell) and 115whrs of LiCo LiPo together for a size reference. They are actually very close in terms of volume, and roughly identical in terms of power and energy. Both are safe for 5C/10C charging.
> 
> The LiCo Lipo has the volume advantage by 22%, and perhaps a %5 weight advantage, but it's not a fair measurement, as the LiCo cells are assembled into a pack with leads/shrink/connectors etc.


 
thanks, that is about the same thing the "specs" say about the li-poly vrses the li-fe flat bagged. But i wasnt sure if the specs were correct, because of the larger differances in Weight-vs-Watt when it is cylindrical. (i thought the specs might have been a copy paste, being a newer item at the time)


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## JaguarDave-in-Oz (Apr 16, 2010)

*Re: Running tests*



SilverFox said:


> Hello JaguarDave-in-Oz,
> 
> When you take a new cell and charge it on your charger, and leave it after it is full for about 24 hours, what voltage does the cell end up at?
> 
> Used cells will end up at a lower voltage, so it is best to use a new cell for this test.


I don't have any unused cells but the one I charged yesterday has only had one or two charges since I bought it from 4sevens. It came off the charger yesterday at 4.18 volts (though that was probably ten to twenty minutes after the light went green because I was busy doing something else) and today almost twenty four hours later it is sitting at 4.17 volts.


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## SilverFox (Apr 16, 2010)

*Re: Running tests*

Hello JaguarDave-in-Oz,

It looks like you will be exceeding the cycle life of the 4.2 volt estimate. If your charger charges all your cells to those voltages you are good to go. Charge often and use them up.

Tom


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## Mr Happy (Apr 16, 2010)

Wow, what a long thread and what a lot to absorb. Somehow I missed all the discussions happening here before now.

Let me weigh in with my own bit of considered ignorance. I am a chemical engineer, though not a specialist in battery technology.

I think that when you are charging lithium cobalt ion cells you _can_ exceed the 4.20 V limit while current flows _up to a point_ but _not beyond_. The argument that the resting electrode potentials "seen" by the cell that add up to the 4.20 V at the terminals is what counts, seems to be correct. If you add some charging current causing the terminal voltage to go above 4.20 V while still not exceeding the limiting chemical potentials at the electrodes, then you will still be fine.

The trouble is that if you do exceed the limiting chemical potentials then you _will_ induce excessive cell degradation and damage. If you charge with too high a current, exceeding 4.20 V by too much, then you _will_ enter this state. You can't just charge at 10C and say the excess voltage can be discounted because it is all down to internal resistance losses. Real chemistry and physics is more complicated and it doesn't work like that. 

Furthermore, nobody can say with certainty where the actual limit is in general terms. It will vary with the size of the cell, the specific chemical formulation and manufacturer of the cell, and with the age of the cell. So if you have any arbitrary 18650 in your hand, you don't know whether the voltage under charge is limited to 4.21 V, 4.23 V, 4.25 V, or what (assuming the resting voltage must never exceed 4.20 V).

Therefore, if you are building a general purpose lithium ion charger and you don't know which cells it is going to charge, then you have to play safe and use a CC/CV algorithm limited to 4.20 V.

If you are a specialist manufacturer designing a system, and if you have rigid control over the cells you are incorporating along with extensive test data on those cells, then maybe you can deviate a bit from the basic guidelines.

For the rest of us, we should follow the manufacturer's recommendations. Personally I doubt that hitting 4.25 V under charging current -- as long as the resting voltage goes no higher than 4.20 V -- will do much harm, but I have no data to back this up.


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## mdocod (Apr 17, 2010)

Howdy Luke, 

Now that I understand this a little better it seems like you are working with cells that are the latest variations of cobalt based tech along-side the phosphate and manganese chemistry cells. Sounds like the latest generation cobalt based cells are pushing into "safe-chemistry" territory with much greater abuse tolerance. 

You are working with many of the latest and greatest cell types available, built to quality standards using the best tech available for safety. Most of the cells being sold to CPF members on the hong kong re-badged express from some-fire brand are likely no where near the level of technology or quality that you work with on a routine basis. 

Questions for you (if you are willing/have time):

Is there any reason to believe that the LiCo cells being targeted to the CPF audience are built to any of these awesome new standards and tech levels? Or would it be prudent to assume that they are probably a few generations behind the greatest safety available?

Several of your posts leading up to these most recent ones suggest a higher degree of safety and abuse tolerance of lithium-ion cells than most of us here believe there is, but after seeing the type of cells you are working with, I don't think we can compare directly. It's very apple to banana to orange if you know what I mean. 

I get the feeling that an ultrafire or even an AW brand LiCo cell is likely quite a ways behind the margin of safety and abuse tolerance compared to most of the cells you are working with. Would you agree?

Regards,
Eric


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## liveforphysics (Apr 17, 2010)

I can't speak for the quality of the cells being provided by AW or DX etc. I've got no clue about the tolerances they use when they build them. 

I have had some friends take trips to china/korea/HK to get factory tours and things to see what the production facilities are like before signing 7-digit contracts for cells. 

I think the general consensus was that only 6 places or so in the world actually manufacture batteries on a large scale. These places make the cells that get labeled as various brands and distributed to various OEMs and wholesalers, who then make them into packs, and/or label them as they like with various re-sale brands. 

I do know just as many cells get rejected for for over-capacity as under-capacity, so maybe the OC cell rejects get distributed to the flashlight markets? I've got no idea even where flashlight cells come from, it's not like anyone ever has or ever will make a battery production run for flashlight cells.


Empirically though, I've tested loads of flashlight cells. 123's, 18650's, 10440's, etc, and from many different brands. Even running through more charge cycles than most flash-a-holics would ever do in years on a cell, I've had zero failures, and I'm testing by setting the cycler up for 4.5-2.8v cycles, so it's not like the're getting cush treatment. I know for a fact they can explode violently if you drain them to zero and reverse charge them. I know they can vent if you leave them at zero volts for an extended period, then re-charge them. But I've simply NEVER seen any number of cycles to 4.5v have any effect on the cell other than an accelerated loss in capacity over time. But, I bet it's less of an accelerated loss in capacity than when most folks store them charged rather than at nominal voltage, or even better, nominal voltage in the fridge. If you get a bad cell, it can blow, it's something bad-cells do, but this isn't the fault of a charger or user error, it's just a cell with a critical flaw. 

I think I've got a way around the large amount of time it takes to get high cycle numbers on a quantity of cells. 

I can strip some 10awg wire, and connect a big long parallel string of all types and varieties of flashlight cells with the same chemistry, all mounted on a board with some labels. Set the cycler for 99 (the most it lets you set at 1 time) and do 1C charge to 4.5v, 1C discharge to 2.8v, and just let the thing run. It will take about 8-9days to run through 99cycles. If no cells show any failures, then I can just set it for another 99cycles and repeat. This way perhaps 50 different cells can all be cycled and tested at once, and in a safe place where any amount of cell venting/pop's/flames etc won't be a hazard. 

It would be great to get some well-used cells in the mix here. How about, if anyone has some cells, in whatever condition that you consider something you would use in your flashlight, mail them to me along with your estimate of the number of cycles on them, age, anything note-worthy etc, and we can get some real-life testing in to see what happens. 

So, any cells you want tested, feel free to PM me for a mailing address, send them, once I get 50Ah of cells (the limit I can 1C charge/discharge on my cycler), I will mount them all nicely on a board with labels, wire them all in parallel, and get the cycler running. 

Maybe certain brands or cell types will consistently fail before others? Maybe none will fail? Maybe some will fail on the first charge to 4.5v? 

It should be great data to get for the safety of handling cells for flashlights. Perhaps the greatest battery safety test ever conducted for flashlights. I don't want any lab-queen cells from Mfg's either, I want the regular stuff you guys get when you order cells, and I want them in the normal used condition, that you would normally just throw back on the charger at home to use again. This gives us the most realistic data, rather than some starting from a brand-new lab-queen cell BS that I always end up getting when we get sample cells from Mfg's or test data from Mfg's (which is never worth a sh*t).


Maybe DX cells blow before AW cells (or visa-versa)? Maybe new cells blow before old cells (or visa versa)? Maybe XXX123's blow more easily than 18650s? Maybe some certian brand/type is on a hair trigger to blow at 4.5v? Maybe none blow with 99 cycles of abusive 4.5v/2.8v charging? Maybe they all blow in the first 10 cycles? 

Maybe take capacity readings before the test on each cell? then after the cell take new capacity readings?

I don't know what's going to happen, but PM me for an address, and I'm willing to put this test together to finally arrive at some answers rather than guess-work and hearsay about battery safety.


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## liveforphysics (Apr 17, 2010)

Nobody is interested in replacing hearsay with test data?


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## VidPro (Apr 17, 2010)

liveforphysics said:


> Nobody is interested in replacing hearsay with test data?


 
I was about to send silver some bad li-poly batteries, and the guy who ships here said "but what about sending THAT through the delivery services" <-- dang people and thier THINKing for themselves.

Which reminded me of how the media freak out about every battery issue, while 100 people a day die in cars. And nobody bans them, each overlyreported such "fact filled" battery story just keeps making them harder and harder to transport. Increasing the price of transport, and putting safety bans on to keep a transport issue from effecting other humans.

So when i thought about sending you some older cells and ones that heat on the charger, and how socially irresponcible it would be to send them through the transport systems, i just ignored it.

for normal testing, the forum is filled with it. for destructive testing YouTube is filled with it. To test something that is internally failing and heating on charge would be cool. After the way you have treated cells your saying you dont have Bad ones?

mabey when i get off the FBI watch list from having "questioned authority" , they would deem that sending known to be defective power items through the mail, was just an error in judgement on my part


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## liveforphysics (Apr 17, 2010)

VidPro said:


> for normal testing, the forum is filled with it. for destructive testing YouTube is filled with it.


 
Has there ever been a test for 4.5v cell cycleing on CPF? Maybe I don't exploit the search engine to it's potential here, but I wasn't able to find a single flame venting charger incident while using _any_ lithium battery charger over the whole history of this forum, or DX's forums. Pleanty of shorting related venting, reverse-charge related venting, over-discharge related damage, etc. But not a single incident I could find anywhere on these forums for someone charging a lithium battery in a lithium battery charger and having it vent flame. 

Am I just missing them in my searches?



VidPro said:


> To test something that is internally failing and heating on charge would be cool. After the way you have treated cells your saying you dont have Bad ones?


 
No. In the history of my playing with any cylindrical cell, I've not found any amount of 4.5v charge cycles that causes anything more than a slow loss in capacity, ending in a tendency for higher self-discharge. 

I've never once been able to make a cylinderical cell go off from 4.5v cycles. This is why I want to do a large test-batch using real cells that get sold to CPF member, in the conditions CPF members keep them in, and set the cycle numbers to 99, and just let it rip. 

I don't understand how this test wouldn't be the wet-dream of every guy interested in flashlight cell Lithium battery safety. Find out which brands/types pop, and how/when it happens. Get emperical real *data *rather than recycled hearsay.


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## VidPro (Apr 18, 2010)

*I don't understand how this test wouldn't be the wet-dream of every guy interested in flashlight cell Lithium battery safety.*

yup :twothumbs, would be better than battery porn. but then not very usefull, because as you well know that cuts into longevity. why would people trying to save $2 by buying cheap cells want to get 1/2 life out of them?
it is like blowing them up, we have seen that, know we can make it happen, cool fun , but it doesnt make the battery last any longer.

Cycles over and over again, of each different cell item at proper specs would be totally cool too. but generally without the TIME added in most people wont Do that many cycles. they do time AND cycles.
so a really usefull test, would be charge and use over 2-3 days, then recharge and use ofver 2-3 days and do that for 3-4 years.
THAT would be the most usefull data.

Various testing (is it UL?) requires that they test by high voltages, damage, and a bunch of stuff , this testing was all done, then things still happend. Spec sheets in quantity told of testing to 5V for safety testing.
stuff still went off, although VERY rarely.

why you cant find the li-ion problems? could some of it be because *were Informed users *? A few years ago there was a story a week being reported. Check out user "Newbie", he listed them often, from Outside the forum mostly. 
i also know of li-ion fires , really wild ones that are not reported here, that happened to people here, if they choose not to tell everyone , thier choice. 

Nowdays on this forum there are more lithium primary incidents. and more li-ion information. smart people, not doing dumb things?
the RC forums still have more incidents reported , even houses burning, li-poly going off in thier cars when charging, using safety containment and having it come in really handy.

If you test a bunch of different cell item at 4.5V cycling, it would be wonderfull, :thumbsup: people will read your results, someone might say well that was stupid, So what, it is stupid, it still would be interesting. Doesnt make it any less great data to see. You want to test different types of cells GREAT, you want to test them outside of specs , then people will point out it is outside of specs, and proves nothing, great, so DO IT.
were all eyes. then test leaving them at that voltage, actually being at that voltage. and that will be stupid, but no less great information to have.


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## liveforphysics (Apr 18, 2010)

VidPro said:


> *I don't understand how this test wouldn't be the wet-dream of every guy interested in flashlight cell Lithium battery safety.*
> 
> yup, would be better than battery porn. but then not very usefull, because as you well know that cuts into longevity. why would people trying to save $2 by buying cheap cells want to get 1/2 life out of them?


 
Not very useful??? It's gaining emperical and unknown safety data on the types and quality of cells used by CPF users. It's not to encourage charging to 4.5v, it's to find the safety boundries for various cells. 

Likewise, in respect to cycle life, most folks keep there cells charged on the shelf or in the light. I would bet 99% of all the cell deterioriation on this forum comes from that over cycles effecting cell life. Generally only the cell in an EDC every accmulates a 3 digit cycle number anyways. 



VidPro said:


> Various testing (is it UL?) requires that they test by high voltages, damage, and a bunch of stuff , this testing was all done, then things still happend. Spec sheets in quantity told of testing to 5V for safety testing.
> stuff still went off although VERY rarely.


 
UL testing is a joke, and non-cycled. CE testing is slightly better. However, we don't even know where the AW or DX cells come from! They sure as hell never did UL testing on the reject cells (or whatever the source) we get to play with. 



VidPro said:


> why you cant find the li-ion problems? could some of it be because *were Informed users *? A few years ago there was a story a week being reported. Check out user "Newbie", he listed them often, from Outside the forum mostly.
> i also know of li-ion fires , really wild ones that are not reported here, that happened to people here, if they choose not to tell everyone , thier choice.


 
I searched the archives. I found zero incidents of a round lithium cell venting flame during charging in any lithium battery charger, from any date. I must have horrible search skills, for something so pleantiful, perhaps you can find one for me?




VidPro said:


> Nowdays on this forum there are more lithium primary incidents. and more li-ion information. smart people, not doing dumb things?
> the RC forums still have more incidents going on , even houses burning, li-poly going off in thier cars when charging, using safety containment and having it come in really handy.


 
LiPoly behavior is not an indicator of the behavior of the cylinder cells we use in flashlights.


----------



## VidPro (Apr 18, 2010)

*it's to find the safety boundries for various cells.* 

you already know (according to you) they can do that, a few time for while. (many of them can) the spec sheets on many of the batteries claim to have tested that and then some.

What they dont test often was charging a cell that internally heats, after it is degridated. we could assume that given enough time you could degrade the cells , THEN test when they begin to internally heat from all the damage. That would be great.
or just have a thermal probe or IR thermal going to see when that starts to occur.

And your going to test this for 3-4 Years right? so the effects of time come into play? or is this more of those accelerated test ?

i have paint on my house that accelerated testing shows it will last 20 years. it lasted 5. I have batteries that in accelerated cycle test they would last 500 cycles , they lasted 50.
i Have a car that went through crash testing, and i aint about to believe that my crashing that car will relate to the testing method they used.


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## VidPro (Apr 18, 2010)

liveforphysics said:


> LiPoly behavior is not an indicator of the behavior of the cylinder cells we use in flashlights.


 
who is we? you dont have any flat flashlights?
i even use li-poly and a prismatic on headlights, because it is lightweight
there are other flat light and users of li-poly more often in the Mods section, there have also been production runs of different lights using flat li-ion cells.
some bike light people have applied li-poly due to size.
plus many people have other devices using prismatic and li-poly.


----------



## liveforphysics (Apr 18, 2010)

VidPro said:


> who is we? you dont have any flat flashlights?
> i even use li-poly and a prismatic on headlights, because it is lightweight
> there are other flat light and users of li-poly more often in the Mods section, there have also been production runs of different lights using flat li-ion cells.
> plus many people have other devices using prismatic and li-poly.


 

Do people charge LiPoly in WF-139s now?


----------



## VidPro (Apr 18, 2010)

liveforphysics said:


> Do people charge LiPoly in WF-139s now?


 
is anyone charging EVs with one :huh:

want to bet we can find one? :santa:
i have charged li-poly 2 times (total) with a cheap china charger (i think they call it DSD).
have you seen the quantity of adaptions done in the past 10 years to various chargers? in the mods section pulling out the curcuits and using them.

So now were off topic, i got a great way to fix that .


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## liveforphysics (Apr 18, 2010)

VidPro said:


> *it's to find the safety boundries for various cells.*
> 
> you already know (according to you) they can do that, a few time for while. (many of them can) the spec sheets on many of the batteries claim to have tested that and then some.
> 
> ...


 
I've got 2 fluke thermal imagers, and 64 channel data-logging and temp probes. Cell temp logging isn't a problem, and only a minor bit of extra work to zip-tie a sensor to each cell as I'm mounting them. 




VidPro said:


> And your going to test this for 3-4 Years right? so the effects of time come into play? or is this more of those accelerated test ?


 
No... This is why using used cells, the cells people actaully run, and have run for years is critical. Otherwise I would just buy 5 of every common flashlight cell on the market new and run the test, but that doesn't give as useful of data to folks charging years old cells with many cycles on them. 


I don't understand where the opposition to this comes from??? I see hundreds of places where yourself and others say charging even a tiny bit past 4.2v is a danger. This is a chance to show the world this is the case, and not just alarmist hearsay.


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## mdocod (Apr 18, 2010)

Hey Luke!

I personally love the idea of such a test. Perhaps we could discuss the finer details of the termination voltages and charge/discharge rates once things get moving along. I get the feeling that the best way to do this would be to start a new thread proposing the idea and moving forward from there. 

Trust me, this proposition you have made is not going unnoticed. 

If you are willing to sacrifice the time to run an extensive test and post all of the independent cell data involved I assure you, it would make for a sticky worthy thread that a great many people would benefit from. 

I am concerned about the method proposed, I think that some prerequisite testing is required to determine if wiring up cells of significantly different resistance and capacity in parallel and then treating them all as a single unit could result in skewed results.

Eric

Oh and PS: I have at least a half dozen cells I would be more than happy to donate for the cause.


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## liveforphysics (Apr 18, 2010)

mdocod said:


> Hey Luke!
> 
> I personally love the idea of such a test. Perhaps we could discuss the finer details of the termination voltages and charge/discharge rates once things get moving along. I get the feeling that the best way to do this would be to start a new thread proposing the idea and moving forward from there.
> 
> ...


 

Right on Mdocod!

As far as resistance in parallel connections go, I've got wire up to #0000awg. I will use a large enough buss wire to ensure less than a few mV of difference between the start and end of each parallel string. And I will charge using CC/CV, so as current drops off, the tiny resistance of the buss wire will have even less of a voltage difference. 

If the cells are all LiCoO2, then the voltage for any of them will relate to the SOC as directly as any charger has means to detect. 


I'm just picking 4.5v as a random point to over-voltage the cells, so it's not as if some cells only going to 4.498v or whatever due to wire resistance is going to be a deal-breaker IMHO. 

PM me for my mailing address, and once I get enough cells, we can get this test started. 

-Luke


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## VidPro (Apr 18, 2010)

i think it would be a great idea. gather up the poor neglected abused cells, and run the test.

*"I see hundreds of places where yourself and others say charging even a tiny bit past 4.2v is a danger. This is a chance to show the world this is the case, and not just alarmist hearsay. "*

but i already learned my lesson

Been there done that .
the reason i NOW say what the experts say, is because i did not do what they said.
SilverFox would always tell me to shuddap about overcharging Li-ion, some cell items i would specifically charge to 4.35V , those cells are ruined and gone now.

if you used the search engine you can find old posts where i would talk Sh$# just like you did, all quite meaningless to them who knew better.

Way back 
I had ~220 Laptop cells (from a vaporware laptop) , running on a scooter, and people would say i should be *balanced*, not charge over 4.2V, next thing i know i have only ~150 of them, as a whole huge parelell bank failed. :shrug:

some of those I kept testing Against thier advice to 4.35v
But using thier advice, I did the testing in the bottom of a garbage can.

eventually i noticed the testing cells about 6 sets of 3 or 4 parellel were heating up more than they were charging. and they werent making it to full charge. those were on the solar charger. 
sooo, 
i took one of those sets and charged it harder to get it to freaking charge. then  something ?? out in the garage went ballistic , that WAS more common around here than you would think, Just go out clean it up lesson learned. (the gas and oil based paints are in the shed)

i continued to set these POS cells up to test different methods to get them to charge unsucessfully, many pulse methods, full cycles , including singing to them with a music charge (really ask silverfox) . basically if i kept the rate down they just got really hot.

so WHY would i agree with any Experts? Because they were right  Dangit.

Why do i say that a *damaged cell can heat internally and can ignite ? Because it can*, and it really isnt difficult to test it , you blew up tons of stuff the fast easy way.
now you can try blowing up something the slow way, THAT is real work 
You showed us hundreds of cells, dont you have some that wont make a full RESTING charge voltage?


----------



## VidPro (Apr 18, 2010)

here is just one of the threads that has recalls and li-ion boom stuff back from the laptop scare days.
https://www.candlepowerforums.com/threads/106242&page=4

there a bunches of links, take this one as an example
http://www.channelregister.co.uk/2005/05/20/apple_recalls_batteries/
then look at the bottom where it "didnt effect anyone"

*The recall comes after the US Consumer Product Safety Commission received six reports of batteries overheating, two from the US and the rest from around the globe.*

Sure all the batteries were "defective, had contaminants" and magically went up, where if they had been perfect batteries this never would have happened, supposedly.
BUT
I had dissasembled many different laptop battery packs during that time, and they werent even Balanced charging capability IN THERE. so? that means batteries COULD be charged over spec , in the series set being hit with voltages.
Many of the packs i took apart the cells HAD properly anode disconnected. they already had overcharged and safely disconnected, is that a defective cell, or a defective chargeing? 
SO
send out tons of batteries that are not being treated proper, and a few people have an issue with. Send out lots of stuff with improper charging and no balancing and lots more people had a fit about it.

start putting in thermal fuses , balancing , cut-offs, and NOW on our cameras they even have a "Cycles" meter built into the battery, and planned cycle obsolecence  which would not be bad, if it didnt register a chargeing cycle from simple topping off :shakehead


----------



## VidPro (Apr 18, 2010)

the main search here used to work better
and the google search get limited
but
http://www.google.com/search?hl=en&...exploded&aq=f&aqi=g10&aql=&oq=&gs_rfai=&tbo=1
it is easy enough to find STUFF that "exploded" lovecpf

https://www.candlepowerforums.com/threads/124776
https://www.candlepowerforums.com/threads/120888
https://www.candlepowerforums.com/threads/128059
http://candlepowerforums.com/vb//showthread.php?goto=newpost&t=262234
https://www.candlepowerforums.com/posts/3286016
https://www.candlepowerforums.com/threads/71161

still cant find the one on a "universal charger" with it switched wrong (high voltage not so high amps) 

theres an App for that 
http://wcco.com/video/[email protected]
laptop fires never . . . oops

if the battery doesnt "explode", mabey the charge can instead 
https://www.candlepowerforums.com/threads/225504
3 out of 3s not bad
http://www.dealextreme.com/forums/Default.dx/sku.4151~threadid.507841
http://www.dealextreme.com/forums/Default.dx/sku.4151~threadid.468204
http://www.dealextreme.com/forums/Default.dx/sku.4151~threadid.456210
http://www.dealextreme.com/forums/Default.dx/sku.4151~threadid.372265
(sorry if these links becomes dead , its par to dissapear things there)

good quote for how to buy a cheap charger "Does anyone know if these explode" :devil:

Quote from loyal customer " did it burn your house down?"

Good justification for buying: "Of course *** sells cheaper and dodgier goods so they explode a little more often. My advice: get over it and stop posting nonsense. And have a nice day." :thumbsup:


----------



## liveforphysics (Apr 18, 2010)

Skimming through there, I found not a single incident of a round cell in a lithium battery charger going off. 

*Lots* of primary 123 cells blowing up (I won't have those things in my house!), lots of shorting related failures, cells mfg'd defective in laptops, balance circuit failures, but I didn't see a incident for a single cylinder Lithium cell venting flame in any lithium charger. 

After 10 years of running them, there has to be at least 1 case of it right? If nothing else, somebody had to have got some cells, thrown them on a crappy charger, and had them vent flame right?


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## VidPro (Apr 18, 2010)

nope never happend. IF your going to include, user error, manufacture error, bad manufacturing, bad chargers , bad cells, lack of balancing, new improved cells with actual vents that work, cylindrical only, properly protected, low charge rates, no damages, no plating, alert users doing all the right things, no cylindrical cell has ever blow up in the history of li-ion.
because the Batery Station ones were defective.

Safest cell in the world, i have always said that. if we get rid of the humans  


*but I didn't see a incident for a single cylinder Lithium cell venting flame in any lithium charger. *
ok, but remember you didnt specify what kind of lithium 
https://www.candlepowerforums.com/threads/250219

there are reports of batteries exploding and catching places on fire On chargers, but not defined for the battery type

i would have to say after hard searching google, it is either the worlds greatest conspiracy, or WE DID IT  nobody blows up single protected li-ions used in flashlights on low rate chargers used properly for years now. 
We have had 1865 Days without a workplace injury 

take for example a google search like this: http://www.google.com/search?num=100&hl=en&tbo=p&tbs=qdr%3Ay&q=%2218650+exploded+on+charger%22&lr=lang_en&aq=f&aqi=&aql=&oq=&gs_rfai=
then try variations of the same, ZERO hits, that is almost unheard of. then change it and put in cell phone
http://www.google.com/search?num=10...odes"&lr=lang_en&aq=f&aqi=g5&aql=&oq=&gs_rfai=
or some famous music player
http://www.google.com/search?num=10...odes"&lr=lang_en&aq=f&aqi=g1&aql=&oq=&gs_rfai=

so we could have these thing completly damage cells as long as , they dont use them anywhere, and dont charge them anywhere else afterwards.


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## liveforphysics (Apr 18, 2010)

Wow! That looks like a hell of a blast! A great reason not to try to recharge a non-recharable lithium cell.

At least you found an incident though! I will count that one.  

The chance of somebody throwing a primary on a charger by mistake is one more reason I refuse to have lithium primary cells in my house. 


Any luck finding a single incident where a cylinder _*rechargable*_ lithium cell vented flame on any lithium charger?


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## VidPro (Apr 18, 2010)

nope, cant find a thing, i dont recall reading any that werent involving human error or purposfull caused ever.

see this thread of lith 1.5v cell rupture, many things like that did not fall under the seperate section, like they do today. that seperate section was added in later.
https://www.candlepowerforums.com/threads/121303
so i cant even find the one i know about with human error.


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## Mr Happy (Apr 18, 2010)

I remember a post by someone who had a lithium battery fire while the cells were on charge in their motel room, causing them to evacuate the room and get into trouble with the hotel management. It was not that long ago, within the last year maybe?


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## VidPro (Apr 18, 2010)

Mr Happy said:


> I remember a post by someone who had a lithium battery fire while the cells were on charge in their motel room, causing them to evacuate the room and get into trouble with the hotel management. It was not that long ago, within the last year maybe?


 
this one?
https://www.candlepowerforums.com/threads/216035
(I just needed more search parameters)


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## lebox97 (Apr 18, 2010)

:huh: that's a buried and forgotten important thread that needs to be moved to the *Smoke and Fire, Hot Cells and Close Calls - The dangerous side of batteries* Sticky?

:thumbsup:
Tod

EDIT: Perhaps the Mods can create a new thread and move the last 2-3 pages of this general Li-Ion charging/hazards EXCELLENT conversation out of this WF-139 Test thread - as we have taken it way off the original topic?




VidPro said:


> this one?
> https://www.candlepowerforums.com/threads/216035
> (I just needed more search parameters)


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## 45/70 (Apr 18, 2010)

VidPro said:


> this one?
> https://www.candlepowerforums.com/threads/216035



Yeah, I remember that one. There are some others around too. There was one I remember, I don't think it was a thread started about the incident specifically, and I've never been able to find it for reference, but a member here (not a newcomer to Li-Ions) had charged an 18650 up in, I believe, a WF-139. All was well, but when he installed it into his light, it got hot and vented. He did notice something wasn't going right, and managed to remove the cell before the light itself could blow, so all it did was vent in his driveway. As I said, I haven't ever been able to find that thread, probably because the thread topic was not specifically about that particular incident.

I've wondered since then, if that was an example of the gradual build up of metallic lithium within the cell due to trickle charging, or....? As has been explained, that's how it can happen, once a cell becomes unstable, you can run into problems at any time, not just when charging so, you never know. I myself, prefer to try and avoid these incidents, however remote the possibilities are. 

In this and the other threads running right now on the Forum, I keep seeing mention of claims that people are saying that if you overcharge or in some other way abuse LiCo Li-Ion cells that they will immediately  and burn your house down, or some such thing. I for one anyway, don't think I've ever said that, and usually mention that probably nothing will happen. What I do bring up, is the possibility that improperly charging LiCo Li-Ion cells _can_ eventually lead to such incidents. In my view, that's one of the scary aspects of LiCo abuse. You may get away with improper handling indefinitely, and then again, you may not. You never know, and that's why I take the stance that it's better to be safe than sorry, and follow proven handling practices.

live, I think the test, you're offering to do, is a great idea. If you get enough cells of the type CPF'ers typically obtain that are in "user" condition, it may show some light on just how dangerous these cells may, or may not be when abused. I would hope also, that you don't show any bias in your testing, as your beliefs in the outcome are already well established. We don't need a "university study" (ie. the outcome is determined before the test is run), or results like the competitors in the alkaline cell and ant-virus software industries come up with, for example, instances where their product is always "#1 after exhaustive testing". You seem to be laid back enough that I don't think this will be a problem. 

Back to the WF-139 itself. You're going to have demonstrate better than you have, to convince me that it's an offshoot from the Chinese space program and not just a basic copycat of the original Pila (non IBC) CC algorithm with a few modifications added over the last few years to make it "better". The facts just don't add up. The wide tolerance components used alone, are enough to show me that it is nothing more than a cheap charger aimed primarily at the CPF community (which probably is responsible for 95%+ of sales) to make a few bucks. And the reason it's still using a CC algorithm, is that it's _cheaper_ to make, not more expensive than a CC/CV algorithm.

I'm sorry, but I won't be able to supply you with any cells for the test. The oldest LiCo Li-Ion cells I have just turned 5 years old last month. They are unprotected RCR123A and 14500 sizes. Both sets of cells, when charged to 4.16-4.18 Volts OC, maintain 4.06+ Volts after resting for 24 hrs. Actually I have 4 of the same AW unprotected 14500's, that I bought about 6 months later that charge to 4.19 volts and read 4.17-4.18 Volts 24 hrs later. These cells however, were not used in my 2AA AuroraLite mini [email protected] hotwire @ 2+ Amps though, and probably only have 20 or so cycles on them in single AA LED lights, that only draw ~1A. I have yet to recycle/dispose of a Li-Ion cell. However I care, feed, and maintain my Li-Ion cells, it seems to work OK. Oh, and for the record, no "venting with flame" incidents either. 

Dave


----------



## mdocod (Apr 18, 2010)

How about this:
http://www.computerworld.com/s/article/9011142/Dell_laptop_fire_destroys_Maine_home

Actually, I like this one better:
http://cbs11tv.com/watercooler/Laptop.Battery.Recall.2.493885.html

This is back in 2006 when *most* laptops were still predominantly 18650 powered. That news article mentions that in the 2 years prior there had been 43 reported incidents of laptop fires. 

Eric


----------



## recDNA (Apr 18, 2010)

*Re: Running tests on the WF-139*

I have a new WF-139. The highest voltage I have ever read coming out of the charger is 4.22 volts with an IMR123.

I now test the battery every once in a while during charging and take it out at 4.1 volts but on the few occasions I've left it in to green it stops at 4.2. I don't know why it went to 4.22 the first time.

With IMR 18650 or RCR 18650 batteries are always 4.2 volts coming out of the charger even if I leave them in for a while after light turns green. I think the longest was about 30 minutes (now I use a timer as an extra precaution against my absent mindedness).

Anyway, this is a very long very technical thread and I can't really discern the verdict on this charger for the CPFers here. Please dumb down the explanation a little. LOL

It seems to me it works well and is recommended by the battery manufacturer I buy from so I'd give it a thumbs up.

Am I missing something?


----------



## VidPro (Apr 18, 2010)

if you want simple, i can SAY it simple, but it wont BE simple still, many factors.

*Like a human would Pour water into a bucket:*
*Really Fast to get the water in, CC *
*then slowing down as the bucket is filled, slowing down as it reaches the top of the bucket. CV*
*then stopping filling the bucket when it is just dripping going in. End CV*

*so all the buckets have the same water in them be it the butcher or the scientist filling them, the scientist just doesnt butcher it as badly *



CC - constant current 
CV - constant voltage.

a proper li-ion charge alogrythm (method) is to charge at the same Rate (CC) to get it ~80% charged
then SLOW DOWN neer the end of charging by switching to CV.

in the CV phase of charging.
the voltage Differance between the battery and the charger by default (easily) slows down as,
the Actual voltage of the cell being charged Reaches the voltage of the charge hitting it.

In the constant voltage Phase:
it slows down because the Difference between the voltage of the Cell itself, and the charge voltage keeps getting smaller and smaller.
when 
There is little voltage Differance between the 2 sources of energy , the "FLOW" of energy (current) between the 2 sources of similar voltage is reduced.
SO
magically the charge rate slows down as the cell is finishing the charge.

Plus , just to complicate it, when the rate of charge is so low (low flow), and the voltage of the 2 items is very very similar, the charge is assumed to be completed , and even the slow part of the charge is then terminated.

So the proper method, treats the battery as best as it can. the "safe" stuff stops everything completely


Also by slowing down at the end, IF the cell will not Charge at all, a charger in the CV phase instead of the CC phase, will be charging at lower rate into a cell that will no longer reach the finish at all.


----------



## mdocod (Apr 18, 2010)

*Re: Running tests on the WF-139*

Hello recDNA,

Testing the voltage of a cell after it is removed from the charger only tells 50% of the story. 

I can go on DX and read a huge pile of reviews of almost every budget charger they sell and find tons of people who got ~4.20V on cells off of all of the chargers you can buy there. 

The question I am asking is, what's happening on the way to 4.20V and what's happening after the fact?

Answering these questions is not a 30 second test, but takes hours of testing to determine. 

The 3rd generation WF-139 is pretty reasonable when used with larger cell sizes IMO because charge voltages aren't going to go much over 4.25V on the big cells. The final termination voltage and charge voltage are 2 different things. 

https://www.candlepowerforums.com/threads/229923

Eric


----------



## recDNA (Apr 18, 2010)

*Re: Running tests on the WF-139*



mdocod said:


> Hello recDNA,
> 
> Testing the voltage of a cell after it is removed from the charger only tells 50% of the story.
> 
> ...


 
Thanks to both of you for answering. I understand your points. 

Now I'd like to press for what I really am looking for - thumbs up or thumbs down.

Let me put it this way. I don't really care if the life of my IMR is shortened. I DO care if it explodes or vents in the charger or worse in the flashlight BECAUSE of something the charger did.

Is the probability of a catastrophic failure in an WF-139 significantly greater than my cell phone charger or laptop charger? 

Is the WF-139 so dangerous to use with IMR123 that the probability of catastrophic failure is higher than .1% IYO? I know there are cases of explosions. There are also a LOT of WF-139's floating around out there so there are bound to be some that are defective just as some laptops and cell phones are.

I'm not really interested in why the Pila is better - just how bad the WF-139 really is.


----------



## 45/70 (Apr 18, 2010)

*Re: Running tests on the WF-139*



recDNA said:


> It seems to me it works well and is recommended by the battery manufacturer I buy from so I'd give it a thumbs up.
> 
> Am I missing something?



OK, I'm curious, which manufacturer do you buy your cells from? I'm not aware of any manufacturer that will sell individual cells to a consumer.



VidPro said:


> ......SO
> magically the charge rate slows down as the cell is finishing the charge.
> 
> Plus , just to complicate it, when the rate of charge is so low, and the voltage of the 2 items is very very similar, the charge is assumed to be completed , and even the slow part of the charge is then terminated.



Aww, come on Vid! "Magically"....."assumed"? 

When a CC/CV charger completes stage 1 (CC), it then goes into stage 2 (CV). Towards the end of the CV stage, when the current drops to somewhere between 0.10C and 0.03C (depending on the charger, _and _C= charge rate), the charge is terminated. There is no magic, or any assumption involved. 



mdocod said:


> I can go on DX and read a huge pile of reviews of almost every budget charger they sell and find tons of people who got ~4.20V on cells off of all of the chargers you can buy there.
> 
> The question I am asking is, what's happening on the way to 4.20V and _*what's happening after the fact?*_



What bothers me about cells that are left on a charger after charge completion, and still read 4.20 Volts, as recDNA observed, is this is a sign that the charger is trickle charging. With all but *very new* cells, the voltage should drop at least 0.01 Volt after the charge has completed. If it doesn't, in most cases, this means the charger is "float charging" the cell, which is a form of trickle charging.

*EDIT:* recDNA, if you pull the cells when the charge is completed, you'll probably be fine. As for the safety compared to your cell phone etc., I can only say that the fact that the cells should be pulled after charge completion, doesn't inspire confidence.

Dave


----------



## recDNA (Apr 18, 2010)

*Re: Running tests on the WF-139*



45/70 said:


> OK, I'm curious, which manufacturer do you buy your cells from? I'm not aware of any manufacturer that will sell individual cells to a consumer.
> 
> 
> 
> ...


 
I buy AW batteries (exclusively) and he sells the WF-139 to go with them. 

It may trickle charge but it least it doesn't go ABOVE 4.2 volts. Most of my cells have only been charged twice counting the initial charge. The IMR123 has been charged 3 times. They are, therefore, pretty new.


----------



## recDNA (Apr 18, 2010)

*Re: Running tests on the WF-139*



45/70 said:


> OK, I'm curious, which manufacturer do you buy your cells from? I'm not aware of any manufacturer that will sell individual cells to a consumer.
> 
> 
> 
> ...


 
They do drop to 4.18 to 4.19 volts but only after about 30 minutes after charging.

So are you saying a trickle charge that never causes the battery to excede 4.2 volts can cause an explosion?

Is the a way to test if this is going on with just a multimeter?


----------



## VidPro (Apr 18, 2010)

i would disagree that float IS trickle charging, just based on the reason they SAY "Do not trickle charge li-ion", is because a Slow continual trickle that goes OVER in voltage, can still ruin the cell.
because you can ruin a li-ion cell by slowly going over the voltage. i have broken li-ion by doing a very slow trickle overcharge

i have not seen any time where a holding Float 4.20 for days and days on end, does anything other than hold its voltage, unless it wont even charge properly.
if it wont charge properly even a CV at 4.20 continues to put current in relative to the voltage differential anyway. (low)
a CC ONLY waiting for a voltage cutoff point, continues at the CC rate when a battery wont reach voltage. (higher)

they use "trickle" to define that it can be pushed over slowly, Float at the "correct voltage" cant push it over spec.

so the application of "dont trickle" was mainly because you CAN go slowly over till gassing, with a small continuing trickle current.


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## Font size (Apr 18, 2010)

*Re: Running tests on the WF-139*




recDNA said:


> It may trickle charge ...


It does not.


----------



## 45/70 (Apr 18, 2010)

*Re: Running tests on the WF-139*



recDNA said:


> I buy AW batteries (exclusively) and he sells the WF-139 to go with them.
> 
> It may trickle charge but it least it doesn't go ABOVE 4.2 volts. Most of my cells have only been charged twice counting the initial charge. The IMR123 has been charged 3 times. They are, therefore, pretty new.



OK, I'm a big fan of AW cells myself, but he is a dealer/distributor, not a manufacturer.

Trickle charging is bad for Li-Ion cells, as it promotes metallic lithium plating out in the cell. This can cause cell instability. It may be that your particular WF-139 version doesn't trickle charge. It appears some do, and some don't. If it doesn't trickle charge, then it is probably safe. In this case however, it still uses a charging algorithm that is not recommended by the Li-Ion cell manufacturers. Is this necissarily a bad thing? That is under discussion here. 

Dave


----------



## Font size (Apr 18, 2010)

*Re: Running tests on the WF-139*




45/70 said:


> ..not recommended by the Li-Ion cell manufacturers.


You have that from AWs cell maker?


----------



## VidPro (Apr 18, 2010)

*Re: Running tests on the WF-139*



45/70 said:


> Trickle charging is bad for Li-Ion cells, as it promotes metallic lithium plating out in the cell. This can cause cell instability.
> Dave


 
continuing to shove current into the battery "trickle" or overcharging or charging in below freezing cold, can cause lithium metal to exist.

which goes back to the claim during laptop scare that it was faulty cells with lithium metal ? when every scientist out there seems to know that you can make a cell faulty with no (series) balancing, causing an overcharge


----------



## 45/70 (Apr 18, 2010)

*Re: Running tests on the WF-139*



Font size said:


> You have that from AWs cell maker?



No, however do you have any information from them that states otherwise? Please enlighten us, if you do.



Font size said:


> > Originally Posted by *recDNA*
> >
> >
> > _It may trickle charge ..._
> ...



I'm curious, how do you know this?

Dave


----------



## VidPro (Apr 18, 2010)

45/70 said:


> but a member here (not a newcomer to Li-Ions) had charged an 18650 up in, I believe, a WF-139. All was well, but when he installed it into his light, it got hot and vented. He did notice something wasn't going right, and managed to remove the cell before the light itself could blow, so all it did was vent in his driveway.
> 
> . . .
> 
> ...


 
From PAG (video batts, sometimes used also for bright video lights)
*If the battery is discharged at an excessive rate, the excessive transition of Ions can bring about a breakdown in the crystalline-layered structure of the plates of a cobaltoxide Lithium-Ion cell. This can lead to a sudden rise in temperature that could possibly ignite the organic solvent of the electrolyte.*

so as usual it could be combinations , creation of a bad cell item, then add in abuse during discharging too.


----------



## recDNA (Apr 18, 2010)

*Re: Running tests on the WF-139*



Font size said:


> You have that from AWs cell maker?


 
My mistake. I thought AW was the manufacturer. I have no idea how WF-139 charges. I was repeating what the previous poster said to make the point the charger isn't putting the battery over the recommended voltage. I didn't know the danger of lithium plating and still don't really.

I keep saying all I care about is safety whereas some here are also concerned with battery life. As long as my batteries charge safely and don't explode or vent I don't care if they only last for 25 charges. In my case that would be years.

I don't mean to be rude, and perhaps I don't belong in this thread, but all I care about is HOW dangerous the WF-139 is or is not.

Does floating cause the lithium plating described? If I remove batteries within 30 min of green light and only charge about once a month won't it take years for a dangerous condition to be exist?


----------



## VidPro (Apr 18, 2010)

*Re: Running tests on the WF-139*



recDNA said:


> I keep saying all I care about is safety whereas some here are also concerned with battery life. As long as my batteries charge safely and don't explode or vent I don't care if they only last for 25 charges. In my case that would be years.
> 
> I don't mean to be rude, and perhaps I don't belong in this thread, but all I care about is HOW dangerous the WF-139 is or is not.
> 
> ?


 
RATE, thermal conditions are heat buildups, the rate on the charger is low. when a cell is ruined, it will be heat that pushes it over, or internal shorts.
when comparing Cell phones and laptops, the heat (insulated from heat removal) and rate is much higher, but on the other hand many of them now have thermal fuseing in them too.
laptop and cell phones have many heat generating other things (hot CPU or GPU), really making the heat situation for the battery worse.
laptop and cell phones user can't as easily observe conditions, like say bulging cellphone battery going unnoticed.

at room temps with the rate, it would be difficult for this charger to ignite even a bad cell it is designed for. but a small internal shorting with localised sharp heating, failures of the charger, still possible.

THEN, the person "adapts" a low capacity battery on and the "charge rate" is higher for the cell type. Arggg.
THEN a person puts on a cell that doesnt have battery protection on it, giving it one more layer of protection. 
Then a person puts a NON-rechargable on it, and certannly blows it up. 

you want a simple answer with no "liability" from the answeree, then you have to make your own choice.


----------



## 45/70 (Apr 18, 2010)

VidPro said:


> so as usual it could be combinations , creation of a bad cell item, then add in abuse during discharging too.



Yeah, it could have been something else. As I remember though, he hadn't yet turned on the light, but it was quite a while back and I don't remember for sure. I looked through my post history trying to find it again, but to no avail. I suppose It's possible I didn't post in that thread, I thought I did though. 



recDNA said:


> I don't mean to be rude, and perhaps I don't belong in this thread, but all I care about is HOW dangerous the WF-139 is or is not.
> 
> Does floating cause the lithium plating described? If I remove batteries within 30 min of green light and only charge about once a month won't it take years for a dangerous condition to be exist?



You're not being rude, rec. You have every right to ask the questions you're asking, and this is as good a place as any.

Yes "float charging" is a form of trickle charging, and is not recommended for Li-Ion cells for the reason I explained. If you pull the cells at charge completion, you should be OK, but it's best not to forget.

As I said, some WF-139's trickle and some don't, so if yours doesn't you should be OK. It's a good idea regardless of what charger you use, to always pull cells after charge completion anyway. There could be an electronic malfunction, for example, even with a high end hobby charger so, it's a good habit to get into.

Dave


----------



## Font size (Apr 18, 2010)

*Re: Running tests on the WF-139*

Good afternoon Dave,


45/70 said:


> I'm curious, how do you know this?


 If+if=Then


recDNA said:


> I buy AW batteries and he sells the WF-139 to go with them.


If recDNA has a late model WF-139 as sold by AW for use on his cells. Then unless defective, the charger does not trickle.


----------



## recDNA (Apr 18, 2010)

*Re: Running tests on the WF-139*

I wouldn't think legal liability would incur due to a post here unless it were false and defamatory. I would think "IMO" makes it clear this is only a matter of opinion.

On there other hand if a distributer or manufacturer assured me that a charger is safe liability would certainly be in place. In fact I think I may infer that guarantee reasonably. 

Back to the subject - I certainly am careful about heat. If a flashlight gets hot it is turned off long before too hot to hold and if it doesn't cool down at a normal rate it's opened outdoors while pointing away from me! (hasn't happened yet thank goodness!)


----------



## Font size (Apr 18, 2010)

*Re: Running tests*




45/70 said:


> some WF-139's trickle and some don't.


For that matter the original Pila trickles also. Newer versions of both chargers don’t.


----------



## mdocod (Apr 18, 2010)

*Re: Running tests on the WF-139*

Hi Dave,

Testing I have seen suggests that the 2nd and 3rd generation wf-139 chargers are not trickle or float charging. 

I too am bothered by a response as simple as "it does not" with no supporting evidence but in this case it is likely correct.

------

Font Size,

The following is a list of li-ion cell manufactures, pack builders, and charger manufactures that only list CC/CV charging as an acceptable and proper charging method in their data sheets:

Panasonic
LG
Sony
Molicel
AGM
BYD
Harding Energy
Maxell
AccuTronics
Sanyo
Saft
UltraLife

If you would like to provide a list of manufactures that recommend a CC/V-Test charging method like the WF-139 I would like to see it. I can't seem to find any myself. 

I feel that you are questioning for questionings sake. I am getting irritated and frustrated by it. 

If you believe that the data sheets of the cell found under the AW wrapper contain this charging recomendation then I am placing the burden of proof on you to prove that it does exist.

Eric


----------



## mdocod (Apr 18, 2010)

*Re: Running tests*



Font size said:


> For that matter the original Pila trickles also.




Incorrect.


(so ha!)


----------



## Font size (Apr 18, 2010)

*Re: Running tests on the WF-139*




mdocod said:


> Testing I have seen suggests that the 2nd and 3rd generation wf-139 chargers are not trickle or float charging.
> 
> I too am bothered by a response as simple as "it does not" with no supporting evidence.


Fair enough!


----------



## VidPro (Apr 18, 2010)

*Re: Running tests on the WF-139*



mdocod said:


> Hi Dave,
> 
> I feel that you are questioning for questionings sake. I am getting irritated and frustrated by it.
> 
> Eric


 
they call that Trolling and Baiting in other forums.
but when Called on it, the troller or baiters will feel justified.
it is bad netiquette , no mater how it is handled is is better to have not existed.


----------



## 45/70 (Apr 18, 2010)

*Re: Running tests on the WF-139*



Font size said:


> If recDNA has a late model WF-139 as sold by AW for use on his cells. Then unless defective, the charger does not trickle.



I'll go along with that. There is an "if" in there, however. 



recDNA said:


> So are you saying a trickle charge that never causes the battery to excede 4.2 volts can cause an explosion?
> 
> Is the a way to test if this is going on with just a multimeter?


 
Sorry rec, I missed this. Often happens when multitasking on the computer.

Yes, as I said, a charger that maintains a cell at 4.20 Volts is float charging.

The way to tell if a charger float charges, or not, is to read the voltage while the cell is charging. A charger with a proper CV stage will charge the cell at 4.20 Volts for, often, half the charge. When the charge terminates, the voltage will drop, usually 0.01 Volt, or more after a few minutes (with the cell still in the charger). The exception to this, is a cell that is very new. In this case, it's possible that you won't see the voltage drop. This is really pretty rare, as most of the cells we get are aged enough that they won't hold 4.20 Volts. Also, in the case of a charger using a proper CV algorithm, the charge current cuts off at somewhere between 0.10C and 0.03C (where "C"= charge current). Depending on the charge rate, the cell (itself) may not actually charge to 4.20 Volts, and the voltage will drop off a bit after charge termination.

Dave


----------



## Font size (Apr 18, 2010)

*Re: Running tests*



mdocod said:


> Incorrect.
> 
> (so ha!)


 [FONT=&quot]That is incorrect, sorry. The original Pilas did not trickle. It probably just kept going until the cell protection circuits shut off. This is if there were any protection circuits.[/FONT]


----------



## recDNA (Apr 18, 2010)

*Re: Running tests on the WF-139*

deleted - question answered in another thread.


----------



## 45/70 (Apr 18, 2010)

OK, one more thing, then I'm outa here. 



VidPro said:


> i would disagree that float IS trickle charging, just based on the reason they SAY "Do not trickle charge li-ion", is because a Slow continual trickle that goes OVER in voltage, can still ruin the cell.
> because you can ruin a li-ion cell by slowly going over the voltage. i have broken li-ion by doing a very slow trickle overcharge



From BU,



> No trickle charge is applied because lithium-ion is unable to absorb overcharge. _*A continuous trickle charge above 4.05V/cell*_ would causes plating of metallic lithium that could lead to instabilities and compromise safety. Instead, a brief topping charge is provided to compensate for the small self-discharge the battery and its protective circuit consume. Depending on the battery, a topping charge may be repeated once every 20 days. Typically, the charge kicks in when the open terminal voltage drops to 4.05V/cell and turns off at a high 4.20V/cell.


[FONT=Verdana, Arial, Helvetica, sans-serif]
This is where I get the idea that *any* trickle charging is a bad thing where Li-Ion cells are concerned. Maybe it's wrong, but Buchmann is pretty on top of things, as far as I know.

Dave
[/FONT]


----------



## liveforphysics (Apr 18, 2010)

Just as a quick reality check for you guys, you know putting 4.2v across any battery (that has resistance, so far that's all of them) that started out below 4.2v, will never reach 4.2v, and will trickle infinitely. 

It's because current can only flow when there is a voltage difference. As the cell voltage approaches the source voltage, the charge rate becomes infinitely slow as the voltage difference becomes infinitely close.

It's called a limit. 

A non-terminated CC/CV charge curve will trickle infinitely if not terminated, and it doesn't make a lick of difference.  It drops to milliamps, then microamps, then nanoamps, then picoamps... etc. You quickly reach a point where it takes years to put 1mAh worth of charge into a cell, well below the self discharge rate of even the best cells. 

Any cell can be left on a 4.2v constant voltage source for any duration of time, by the laws of physics, it MUST continue to trickle charge, yet the cell will never become overcharged, damaged, over-volted, and it's impossible for the cell to ever exceed 4.2v. 






Anyways... I've had a few people email for my address with cells to send me for testing. Lets get some more in the mix. Write your CPF name on them in a sharpie and a number of your estimated cycles onto the cells to make it easier for me to keep them straight. 

-Luke


----------



## VidPro (Apr 18, 2010)

45/70 said:


> OK, one more thing, then I'm outa here.
> 
> 
> 
> ...


 
is on top of things.

*Instead, a brief topping charge is provided to compensate for the small self-discharge the battery and its protective circuit consume. Depending on the battery, a topping charge may be repeated once every 20 days. Typically, the charge kicks in when the open terminal voltage drops to 4.05V/cell and turns off at a high 4.20V/cell. *

which is the re-topping alogrythm style choosen for many battery types sort of. just let it go down, then punch it up.
vrses trying to float forever.

They wouldnt have included the complete stop in Primo charging systems if it was a waste of thier time. plus it stops everything, no undesired after effects, no surprises, untill the wall power fails and resets it ,like some things will.

but 4.05? a bit strange when a good cell can be sitting .01V from it's original charged state for 6months. 
maby in 2 years a good unproteced cell wont have dropped .15v.
Charge to 4.20, rest at 4.19 and a year later go back to a good unproteced cell and the voltage can still be reading >4.13 . Voltage isnt everything, but the self discharge of the good cells looks good.
even protected many things are holding voltage months later.
mabey they are also including some chargers , status lights, metering and all, putting a very light drain on it.


----------



## mdocod (Apr 19, 2010)

liveforphysics said:


> .....
> A non-terminated CC/CV charge curve will trickle infinitely if not terminated, and it doesn't make a lick of difference.  It drops to milliamps, then microamps, then nanoamps, then picoamps... etc. You quickly reach a point where it takes years to put 1mAh worth of charge into a cell, well below the self discharge rate of even the best cells.
> 
> Any cell can be left on a 4.2v constant voltage source for any duration of time, by the laws of physics, it MUST continue to trickle charge, yet the cell will never become overcharged, damaged, over-volted, and it's impossible for the cell to ever exceed 4.2v.
> ...



Hi Luke,

None of us are trying to claim that a clamped float charge at 4.20V will ever result in a cell voltage in excess of 4.20V. As you have pointed out, with most cells the charge rate will just keep getting lower and lower as the gap between the charge voltage (float) and the cell voltage get closer and closer together. If the cell had absolutely zero self-discharge effect and charged with 100% efficiency, then it would still sit there and keep cutting the cheese into smaller and smaller blocks until the end of time..

The problem does not stem from over-charge in this case. And with brand new cells, there is also very little problem as a brand new cell could be charged to 4.20V and hold there in a resting state for weeks, in which case, having a 4.20V float attached to it would have almost no measurable effect on cell wear and tear. When limiting the discussion to young healthy cells, I agree that a float charger is not likely to cause any harm to anyone. 

The problem arises when you have a cell that has a few hundred cycles and a few years under it's belt. It is when li-ion cells are reaching middle and late age that they pose greater risk, especially when the charging requirements are ignored. 

Older more worn out cells will naturally settle to 4.10V or less within a few hours after charging. Taking a cell like this and floating it at 4.20V will require substantially higher continuous trickle rates. Those trickle rates will be translated into unnecessary wear and tear and chemical changes within the cell. 

This is compounded by the fact that many of these floaters are actually going to float ~4.25V or higher if allowed to do so. So not only are they float/trickle charging, they are floating to a voltage that is proven to reduce cycle life quite substantially even without improper charging.

Eric


----------



## liveforphysics (Apr 19, 2010)

Tom (CPF member SilverFox) and I had a great long phone conversation last night. Tom is a great guy, and we've got some pretty solid ideas for the cycle testing.


I've also contacted a friend at lawrence livermore national lab's, which does exhaustive battery testing for military battery applications. He is willing to help us with some electron-microscope time on the current collector surfaces in the cells to check for lithium metal plating, or other potential problems.

Tom is sending a wide range of cells for testing, and I still need more from you folks out there.  

PM for address.

-Luke


----------



## kitelights (Apr 21, 2010)

*Re: Running tests*



Font size said:


> For that matter the original Pila trickles also. Newer versions of both chargers don’t.





mdocod said:


> Incorrect.
> 
> 
> (so ha!)


Eric, actually I believe his statement regarding the Pila is correct. I forgot my source, but I've done two major GBs for the Pila and somewhere along the line I picked up the info that the original version of the Pila was not what the current version is and is not recommended.


----------



## Font size (Apr 21, 2010)

*Re: original version*




kitelights said:


> original version of the Pila was not what the current version is..


 [FONT=&quot]I think what he means is that the first Pila’s does not trickle. Pila’s probably just keeps going on full blast. Trickle implies that it slows down. [/FONT]


----------



## liveforphysics (Apr 21, 2010)

*Re: original version*



Font size said:


> [FONT=&quot]I think what he means is that the first Pila’s does not trickle. Pila’s probably just keeps going on full blast. Trickle implies that it slows down. [/FONT]



lol, now you're putting the bait on heavy. 




So, getting serious here, we've got cell samples coming from 6 different CPF users now, I've got enough new cells to do the testing of course, but it would be much better to get some old well used cells that have taken the real-world abuse of flashlight use from you guys, so the tests are as relevant as possible.

We will have cell plates checked at Livermore national labs for lithium plating for certain.  And we've got a new test idea for some of the cells to hopefully make plating as likely to happen as possible, so we get a real answer about if metallic lithium plating is indeed possible. For this test, we're going to take separate batch of cells, and just let them sit on a 4.5v CV supply for days, weeks, what ever it takes. Then test some of the cells for capacity, Ri etc, and ship some of the cells down to Livermore national labs to inspect for any signs of metalic lithium plating. It should be neat to see what results we get. 


So, a few more folks with batches of well used cells laying about, PM me, lets get them mailed in, and lets get these tests started!


----------



## Mr Happy (Apr 21, 2010)

I could be way wrong here, but isn't lithium plating a risk from under-volting cells? How about also discharging some cells down to 1 V or so and letting them sit there for a while?


----------



## ampdude (Apr 21, 2010)

Scratch my previous comment, my WF-139 (newer version) does sometimes charge the IMR16340's to 4.24-4.25 volts.

I just measured yesterday, one was charged to 4.25 and the other charged to 4.23 when it cut off.


----------



## liveforphysics (Apr 21, 2010)

Mr Happy said:


> I could be way wrong here, but isn't lithium plating a risk from under-volting cells? How about also discharging some cells down to 1 V or so and letting them sit there for a while?




An equally good test. 

Get some more cells sent in here, and we will do a batch held at 1v while another batch is held at 4.5v, and another batch is doing 1C cycles from 4.5-2.5v. 



I did a test yesterday running some 18650's on the cycler, telling the cycler it was a 4S NiCd pack, and to charge to 4.8v, then discharge to 0v, and keep cycling. So far, the only excitement has been slight cell warmth.


----------



## NutSAK (Apr 22, 2010)

*Re: original version*



Font size said:


> [FONT=&quot]I think what he means is that the first Pila’s does not trickle. Pila’s probably just keeps going on full blast. Trickle implies that it slows down. [/FONT]





liveforphysics said:


> lol, now you're putting the bait on heavy.



I think that's correct. Some have stated that the early Pila relied on the battery protection circuit to terminate charge. So, it didn't "trickle", it ran CC until termination.


----------



## mdocod (Apr 22, 2010)

*Re: original version*

Yes, the original Pila charger, Pre-IBC, worked the same way that Wolf-Eyes chargers still do today. Charges pretty fast at a constant CC rate till the charge voltage runs into the PCB.


----------



## VidPro (Apr 22, 2010)

liveforphysics said:


> An equally good test.
> 
> Get some more cells sent in here, and we will do a batch held at 1v while another batch is held at 4.5v, and another batch is doing 1C cycles from 4.5-2.5v.
> 
> ...


 
from various readings on the web the deep discharge damage is different, if you want evil lithium metal plating stuff, then you keep it high charged. the deep discharge will still turn it from battery to resister, but from what i am reading it wont cause the "li plating", or at least not the same way. IF the attempt is to make a "dangerous battery" not just a lump of coal, the chemical experts say its on the high end.


----------



## liveforphysics (Apr 22, 2010)

http://www.electrochem.org/meetings/scheduler/abstracts/214/1282.pdf


From what I've understood, plating simply doesn't happen in cells with modern anode/cathode design unless you try to throw a very rapid charge into a cell that is in a deep freezer. 

Warm modern cells just can't get lithium plating, and IMO it's a pitty, because it's a totally reversible process on discharge, and it would be a great capacity and discharge voltage boost to do when charging a pack up for a race event. Maybe I should try sticking a pack in a cooler with dry ice, then rapid charging, and see if I can get a higher average discharge voltage out of it.


----------



## liveforphysics (Apr 22, 2010)

A bit of history that some folks might enjoy. 

The first Lithium secondary cells had better capacity, and power density than our modern cells. 

This is because they weren't lithium ion, they were lithium metal. In charge, electrolysis transfered the plated lithium metal from anode to cathode, and to discharge, it traveled back. These cells had outstanding energy and power, and were refined to be capable of a generous cycle life. Sadly, they never found a solution to the very real safety problems associated with the cells, so they had to move to using Lithium Ions rather than metalic lithium.


----------



## mdocod (Apr 22, 2010)

Howdy Luke,

I recall reading about those original lithium metal based rechargeable cells on numerous places online. IIRC they were experimenting with that tech back as early as the 1970s. I guess the conclusion was that lithium metal cells would remain primary single use cells as that was the only way to take advantage of the energy density without serious danger. It stands to reason that modern li-ion cells should be relatively safe, considering they have been in the market now for nearly 20 years. Perhaps some of the things they have learned in the last 20+ years about making li-ion cells safer could lead them to a solution for the hypothetical lithium metal secondary cells of the future. 

Hopefully this abuse testing will offer up some clues as to how "modern tech" these various flashlight oriented cells really are. 

Eric


----------



## 45/70 (Apr 23, 2010)

liveforphysics said:


> Get some more cells sent in here, and we will do a batch held at 1v while another batch is held at 4.5v, and another batch is doing 1C cycles from 4.5-2.5v.
> 
> 
> 
> I did a test yesterday running some 18650's on the cycler, telling the cycler it was a 4S NiCd pack, and to charge to 4.8v, then discharge to 0v, and keep cycling. So far, the only excitement has been slight cell warmth.



I don't think that cycling the cells the way you're doing replicates the conditions of actual use these cells see in our flashlights. As I understand it anyway, the time spent at either voltage extreme is a major factor, as far as damage that occurs to the cell. The shorter the time spent at either extreme, the less damage that the cell will incur. Racing through a number of cycles isn't going to accomplish much, as for the most part, the cells will be somewhere in between were they are happiest anyway.

You need to keep cells at both extremes for a few days, for instance, between cycles for this test to approximate actual use. Most people charge their cells up and then use them at some later time. The same applies for when a cell becomes discharged. It's fairly rare, for me anyway, to immediately use a cell after charging it, or drop it in a charger the instant it's depleted.

It doesn't look like you're getting much of a turnout. I thought again about a few of my cells, but really, they've never been exposed to any of the conditions that would affect them in a bad way, and as I said, they're all at 85%+ condition anyway. Hope you get some more cells.

Dave


----------



## NutSAK (Apr 23, 2010)

I unfortunately just recycled several 18650s and 16340s that were at 60% original capacity (my cutoff point). I would have gladly sent them in for testing. I probably won't have any others to hit that spec for another 1-2 years.


----------



## bthrel (Apr 23, 2010)

I have 10 of the IMR's salvaged from a Ryobi P104 lithium pack, all seem good, but from my research not good for typical flashlight applications as they are low capacity and designed for high current (1200mAh @ 6A/12A).

Info on these batteries here .. http://www.toolboyworld.com/eBay/Ryobi_Batt_Rebuild.htm
 
If they are needed for destructive  information gathering I gladly send them to whomever... 

Brian


----------



## recDNA (Apr 24, 2010)

Ok, I followed the directions to measure voltage on my 139 charger while charging an IMR16340 with a spacer.

Although the battery is at 4.15 volts when disconnected (immediately then drops a little), the voltage measured at the + and - pole during charging goes as high as 4.32 volts. I would normally stop charging at 4.1 volts but I wanted to see how high it would go.

So is 4.32 volts while in the charger dangerous? Remember, the second I disconnect AC to the charger the voltage of the battery is under 4.2 volts

You know what? I've had it with this. I'm buying a Pila. Tonight if possible. Can anybody recommend a good dealer who carries this charger?


----------



## mdocod (Apr 24, 2010)

recDNA said:


> So is 4.32 volts while in the charger dangerous? Remember, the second I disconnect AC to the charger the voltage of the battery is under 4.2 volts



That is the question we are all asking. Luke believes that with modern li-ion cells using charging voltages in excess of 4.25V is not a problem provided the cells state of charge is not brought above 4.25V (except where higher voltages are specified safe by the cell manufacture, some are up to 4.35V now). Luke (liveforphysics) makes an excellent argument for the case explaining that separator materials used in these cells should be able to handle a voltage differentials 10 fold what they see in normal service before problems develop. 

On the other hand, we have pretty much every consumer product that uses li-ion cells using a CC/CV method or a modified version of CC/CV that does not exceed ~4.25V during charging. We also have every manufacture spec sheet we can dig up specifying the use of a CC/CV charge method with termination based on current dropping to some a specified current or to a specified C rate. 

We have some reports that CC only charging seems to have reduced the life of cells for folks. It's possible that those cells would have lived short lives regardless of how they are charged so we will never know for absolute sure based on just reported experience from a limited number of people. 

As I originally observed, and is still true, the WF-139 is going to reach higher charge voltages on smaller, higher resistance cells. With large lower resistance cells, the charge voltage doesn't go much beyond 4.25V hardly at all. I wouldn't fret too much about a charge voltage of 4.26V (guessing it would probably be around there but not sure) on a big 2600mAH 18650. I think if there is a problem with these "elevated" charging voltages, then it is likely going to be most prevalent in the smaller cell sizes that go over 4.30V charge voltages in the 139. 

Check out flashlightz as a place to get an IBC. 

Eric


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## recDNA (Apr 24, 2010)

Thanks Eric. I finally read the entire thread. It's a little torturous taken all at once but I get the idea. Seeing that this is way over my head I don't think I really CAN make a truly informed decision.

The one thing nobody seems to disagree about is that the Pila charger IS safe. (Please don't tell me it isn't). I ordered one 5 minutes ago while still head up about it. In an hour I'll regret "wasting" the money but I'm all about the safety.

The fact is I'm pretty sure my new WF-139 IS safe. I don't really care about 300 cycles vs. 500 cycles. I'll replace the battery long before that. I'm very comfortable using it with my protected 18650. The voltage doesn't ever exceed 4.25 volts in while charging and the battery is 4.20 the second I turn off the charger.

My IMR16340 is another matter. The voltage is getting over 4.32 volts while charging and I quit before the green light came on. When I wasn't measuring voltage I charged it a couple of times to green. Goodness knows what the max charge was. When the battery was taken off it was never higher than 4.21 volts so I felt pretty safe.

IMR's don't vent with flame but they can give off stuff I don't want in my house. IMR's are not protected so there is no added safety like in my 18650 protected cells. IMR's have very low resistance so they may be especially susceptible to damage from very high voltage while charging.

I'm probably wrong in all of my "logic" because I have so little background in electronics but one thing seems clear to me...if I want to be as safe as I CAN be without spending 100's I don't have on a hobby charger the Pila is my best choice.

I often spend more than this charger cost on dinner. How can I justify NOT trying to be as safe as I can be?

Still, there is a little voice in the back of my head saying "sucker!". Oh well. It's done now. I hope the Pila works well!



*BTW, kind of late to ask but is the Pila a good choice for IMR16340? Most of the batteries discussed in this thread are protected and have higher capacity.*


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## old4570 (Apr 24, 2010)

Wow - Yeah one has to wonder about the WF-139 

Just checked mine ...

Open circuit = 4.95v 
1celll occupying = 5.15v [ empty bay ] 
Measuring circuit with cell = 0.88v 
Batt @ 4.04v 

Charging at 200-300mA [ varies ] 

Compared to Trustfire - TR-001 

Open circuit = 4.21v 
1cell occupying = 4.21v [ empty bay ]
Measuring circuit with cell = 0.18v 
Batt @ 4.04v

Charging at 170mA

Shekor Charger

Open Circuit = 4.15v and 4.17v [ each channel ]
1 Cell occupying = 4.15v and 4.17v
Measuring circuit with cell = 0.11v and 0.14v 
Batt @ 4.04v

Charging @ 140mA


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## mdocod (Apr 25, 2010)

Hello recDNA,

I prefer the Pila IBC for all cells from RCR123 (16340) size and up regardless of whether they are IMR or not.

Honestly, given that the small cells you are charging are IMR16340s, which are inherently more abuse tolerant and safer, and the large cells you are charging are not exceeding 4.25V during charging, I would have felt pretty comfortable just sticking with the WF-139 for your purposes. The Pila will give some nice piece of mind and will charge faster than the WF139 so all in all not a bad investment regardless, and if you ever need to top up more cells at once your 139 can be on backup duty. 

Eric


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## JB (Apr 25, 2010)

Quick question: I see the term "hobby chargers" mentioned a few times. And these seem to be a step above the "normal" chargers like the WF-139 or IBC. What exactly are "hobby chargers"?


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## VidPro (Apr 25, 2010)

JB said:


> Quick question: I see the term "hobby chargers" mentioned a few times. And these seem to be a step above the "normal" chargers like the WF-139 or IBC. What exactly are "hobby chargers"?


 
the chargers that the RC (radio control) people made popular
http://www.hobbypartz.com/lipochargers.html
often they will do ni-mh , ni-cd, and Lead Acid, and li-poly and li-ion, in series or singles, have charge and discharge , now have cool readouts and now balancing connections. sort of a All-In-One microprocessor controlled muti-alogrythm multi-current multi-cell possible charger thing.
even cheap ones now have CC CV , control of everything, safety max capacity or time cutoffs, and the whole gambit of charge and discharge capability.
Which just leave the HUMAN having to, and being able to, control all aspects of it.
can be made "safer than" or can be set "incorrectally" 101 ways to completly destroy something  Versatility to the max.


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## mdocod (Apr 25, 2010)

Hello JB,

Best way to explain is actually just to show them:

Hobby Chargers

Do a search for Schulze chargers if you want to see some really fancy stuff!

Eric


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## JB (Apr 26, 2010)

VidPro said:


> the chargers that the RC (radio control) people made popular
> http://www.hobbypartz.com/lipochargers.html
> often they will do ni-mh , ni-cd, and Lead Acid, and li-poly and li-ion, in series or singles, have charge and discharge , now have cool readouts and now balancing connections. sort of a All-In-One microprocessor controlled muti-alogrythm multi-current multi-cell possible charger thing.
> even cheap ones now have CC CV , control of everything, safety max capacity or time cutoffs, and the whole gambit of charge and discharge capability.
> ...



Thanks for the link. Wow's that opening up a whole new kettle of fish when it comes to chargers.


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## JB (Apr 26, 2010)

mdocod said:


> Hello JB,
> 
> Best way to explain is actually just to show them:
> 
> ...



Saw that link. Also did a search on Schulze chargers... fancy stuff indeed. Fancy price too 

What I notice is that most of these have a fancy looking "controller" (if that's the right word). But I don't see any cradle to hold the batteries. Is that optional? Or some other connection to the battery is used? I see those black/red leads... are those used to "manually" connect to the batteries?


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## VidPro (Apr 26, 2010)

JB said:


> But I don't see any cradle to hold the batteries. Is that optional? Or some other connection to the battery is used? I see those black/red leads... are those used to "manually" connect to the batteries?


 
and that is where the fun starts 
there are many cradles hand made in the forum, and using that word "cradle" in the search with "li-ion" and "charging" or "hobby", is likly to find some of the designs. Also "magnet"ic bannana leads, and battery "tray"s and all discussed fluently.


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## DM51 (Apr 26, 2010)

Here's a link to a thread by sdnative, who makes various different-size cradles.


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## mdocod (Apr 26, 2010)

Hobby chargers are normally intended for use with battery packs that are already all soldered or welded together and then shrink-wrapped up into a single unit with a bungle of wires coming out and a nice plug. Balance taps for li-ion packs are often pre-wired into the pack and right on the multi-pin plug. 

Using these chargers for loose cells requires that the user either build apparatus for mounting and connecting or buy something to assist in this particular challenge.


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## mr.snakeman (Apr 26, 2010)

Just thought I´d share my latest charging experience with you all. I thought I would measure the charging voltage of my UltraFire WF-139 (new model) charging an AW protected 14500 using the method mentioned in HKJ´s DMM user guide (see the link in post #265 above). The DMM used is a Caltek CM3900A. The voltage rose up past 4.2 volts before the diode turned green. From the time that the voltage rose above 4.2 volts until the charger diode turned green was only a few minutes, but when it did change the voltage measured 4.65 volts (remember, this was a one-off test). This was only for a few seconds as I terminated the charging process as soon as the diode changed color. The charging current fluctuated between 380-410mA. The 14500 measured 4.18 v. directly after charging and 4.17v. about ½ hour later. I think I´m going to order a Pila IRC and retire my WF-139.


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## mdocod (Apr 27, 2010)

Hello Mr.Snakeman,

Very interesting results!

Something to consider:

It's _possible_ to introduce substantially increased resistance from the charger to the cell when conducting tests with a DMM to monitor charging. Poor connections are generally the cause of this. When this happens, the charger naturally offsets this with higher voltage to maintain the charge rate it is shooting for. When the WF-139 does it's little "pulse" testing for cell voltage every second or so, the increased resistance has very little of any effect on the actual V-test because there is no significant load for the test.

It is very unlikely that the charge voltage is _actually_ 4.65V under normal charging conditions. When the actual charge voltage exceeds ~4.35V, the protection kicks in and terminates the charge. Which is probably what actually happened, considering that your final resting voltage was below 4.20V. 

It's also possible that if the contacts on your WF-139 or the ends of your cell are oxidized, that you could get these abnormal results. 

Remember: V/R=I

In the case of charging a cell, the "V" in this equation is the voltage differential between the cell and the charger. A decent protected 14500 might have a total resistance of around 0.4ohm. Your 139 was running around 400mA so here's the equation:

V/0.4=0.4
V=0.16

Charge voltage differential = 0.16V required to maintain 400mA charge rate. Cell achieves ~4.18-4.19V SOC when the charge voltage reaches ~4.35V and the PCB trips, terminating the charge. 

Hitting 4.65V charging voltage would require that your total resistance was over 1 ohm.

Eric


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## mr.snakeman (Apr 27, 2010)

Thanks for your feedback, I´ll check all the contacts and try again when I have time and see if I get the same results (or not).


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## march.brown (Apr 27, 2010)

mr.snakeman said:


> Thanks for your feedback, I´ll check all the contacts and try again when I have time and see if I get the same results (or not).


If you have another meter (or can borrow one), try measuring the resistance of your ammeter plus its leads on the different ranges ... Each ammeter range will measure a different value in ohms ... This is why some CPF'ers measure the voltage across a resistor inside the charger and work the current out from that (ohms law) ... I tried to measure charge current and had a different reading on each current range of the meter ... I gave up in the end and just check the cell open circuit voltage nowadays.

As a matter of interest , if you know the resistance of the ammeter plus leads and you know the current as measured on the ammeter , you can calculate the voltage across the ammeter and leads ... The actual voltage across the cell will be reduced by this amount.
.


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## HKJ (Apr 27, 2010)

march.brown said:


> As a matter of interest , if you know the resistance of the ammeter plus leads and you know the current as measured on the ammeter , you can calculate the voltage across the ammeter and leads ... The actual voltage across the cell will be reduced by this amount.
> .



Why not measure the voltage directly across the cell? It is much easier.


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## JB (Apr 27, 2010)

Thanks for all the feedback on hobby chargers and their accessories. Opened up a new perspective for me.


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## recDNA (Apr 30, 2010)

mdocod said:


> Hello recDNA,
> 
> I prefer the Pila IBC for all cells from RCR123 (16340) size and up regardless of whether they are IMR or not.
> 
> ...


 
Well my PILA arrived and I've tested it a few times now I like it. It only charges to 4.17 volts (IMR or protected 18650 or 16340 all quit at 4.17 volts) that's OK with me. I know I could hit reset and pack a little more energy in the cells but would the runtime at 1.5 amp be significantly increased by jacking the voltage up to 4.2 volts?

Thanks Eric

(BTW, I'll still use the WF-139 with protected 18650 when I'm charging more than 2 at time. I actually thought it was a great charger until reading this thread and I still feel pretty comfortable with it. I just find myself charging more often so in the long run I thought the PILA would be a good investment)


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## old4570 (Apr 30, 2010)

Well , I did one to completion ..

Batt 4.2v Voltage from charger 4.24v , with green light , I get no current ...

My test set up seemed for some reason to restart the charge cycle , which does not seem to happen with just a 18650 in place .. 

Just uploading the video now of the 139 completing the charge , as I said , my test rig seems to kick start the charge cycle ... Anyhow , if you like watching a AMP meter , gratuitous action video .... http://www.youtube.com/watch?v=1Gk6vevQnBY

Update : Well I was able to measure current @ 200mA setting and 20mA setting when the green light came on and there is no trickle charge ...

So , if you have a 5v open circuit WF-139 , then it does not [ mine dont ] trickle charge on completion ..

I tried it with an unprotected cell , both channels and no current on green light ...

So as near as I can tell , there are two issues ... Open circuit voltage / stand by voltage / and the way it charges [ pulsing ] 

I made a separate post as I captured the pulsing on video [ 1A meter ] 

I dont think the open circuit voltage is anything to worry about . as once the cell goes in it changes to charging voltage ...


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## JHCANDLEPOWER (Jul 9, 2010)

*WF139 reading 0 volts on open circuit*

Hi,
Bought the WF139 before reading this forum....doh!
It came with two Ultrafire 18650 blue labels. The battery both had a voltage reading of 3.8V. Just to examine the charger regarding the old vs new concept, I connected one lead from the meter to the positive terminal and the other lead on the negative sliding terminal. The meter read 0.09. Has anyone seen something other than 10-11v and 5v? I haven't seen a mention of ~0v during open circuit. By open circuit, I attached the leads as described and plug the charger into the wall (no batteries). The light flickers from red to green very quickly. I know the charger is working as the batteries are now at 4.1v after a two hour session.

Is this possibly another revision?


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## old4570 (Jul 9, 2010)

*Re: WF139 reading 0 volts on open circuit*



JHCANDLEPOWER said:


> Hi,
> Bought the WF139 before reading this forum....doh!
> It came with two Ultrafire 18650 blue labels. The battery both had a voltage reading of 3.8V. Just to examine the charger regarding the old vs new concept, I connected one lead from the meter to the positive terminal and the other lead on the negative sliding terminal. The meter read 0.09. Has anyone seen something other than 10-11v and 5v? I haven't seen a mention of ~0v during open circuit. By open circuit, I attached the leads as described and plug the charger into the wall (no batteries). The light flickers from red to green very quickly. I know the charger is working as the batteries are now at 4.1v after a two hour session.
> 
> Is this possibly another revision?



Could be , I had a feeling that a another revision may have been made . 
It would be nice if Ultrafire actually marked the chargers with the production revision .


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## Bullzeyebill (Jul 9, 2010)

*Re: WF139 reading 0 volts on open circuit*



old4570 said:


> Could be , I had a feeling that a another revision may have been made .
> It would be nice if Ultrafire actually marked the chargers with the production revision .



Yes, that and use a CC/CV algorithm. What keeps these folks, all of them that produce so called Li-Ion chargers from doing that?


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## 45/70 (Jul 10, 2010)

*Re: WF139 reading 0 volts on open circuit*



Bullzeyebill said:


> Yes, that and use a CC/CV algorithm. What keeps these folks, all of them that produce so called Li-Ion chargers from doing that?



Profit margin ($$$).  In order to accomplish this, they would have to upgrade the quality/tolerance of the components used. I wouldn't be surprised If dealers are paying $2-$3 for these chargers now. If the dealer's price went up $5, they'd have to charge $30-$45 for them to keep their margin.

I can hear people complaining now, about how they'd have to pay as much for a Li-Ion charger as they do for a NiMH/NiCd charger. Makes sense to me, but......

Dave


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## rocled (Jul 10, 2010)

My WF-139 has an open voltage of 4.9V. I purchased it 1 year ago. I only use protected cells, so will this charger be safe for me as long as I remove the batteries as soon as they are charged? Thanks for any input.....


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## 15miki15 (Aug 24, 2010)

Is WF-139 charging method good? Or it is destroying faster that "classic" method lowering current (no CC/CV)? Iam thinking to buy it. I do not plan spending a lot of money for Pila charger.


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## old4570 (Aug 25, 2010)

There is no evidence the WF-139 damages cells ..
If you buy a cheap charger , and cheap nasty batteries , and the cheap nasty batteries fail or degrade ?? Do you blame the charger , or the cheap nasty cells .

All chargers are some what safe when monitored ... 

I just tested a charger that fried itself after charging one battery , not what I would call a safe charger .... The WF-139 does the job , and it does it well for the price you pay ...


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## David Cameron (Mar 13, 2011)

I just received my WF-139. With no battery in a slot the reading is 4.25 V on each slot. When an almost fully charged battery(3.99 V) type 18650 is put in the slot the reading is 4.01 V. This charger for all intensive purposes charges to 4.2 V. People who have posted seem overly concerned about the last .05 V without taking into account the internal resistance of the battery. This resistance is overcome by charging voltage being higher than target battery voltage. This is not a sophisticated multistage charger but it does appear to safely charge the 18650 cell. There is no such thing as constant current AND constant voltage charging. Either voltage is varied to maintain a constant current through the varying resistance of the battery or the voltage is held constant and the current varies as the battery internal resistance varies. I prefer constant voltage with a current limiter


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## DM51 (Mar 13, 2011)

David Cameron said:


> I prefer...


To those who ask how it is possible for someone to run a country and still find time to try and sound knowledgeable about battery charging, my usual response is "It is not easy at all."


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## Mr Happy (Mar 13, 2011)

David Cameron said:


> There is no such thing as constant current AND constant voltage charging.


There is such a thing as constant current OR constant voltage however, which is what a CC/CV control algorithm is supposed to do.


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## 45/70 (Mar 13, 2011)

David Cameron said:


> ......This is not a sophisticated multistage charger but it does appear to safely charge the 18650 cell. There is no such thing as constant current AND constant voltage charging



This is why a charger that utilizes a two stage process is prefered (from Battery University). The first stage is CC and when the _circuit voltage_ reaches 4.20 Volts, in the case of a LiCo cell, stage 2 begins, which is the CV stage. A charger which utilizes these two stages therefore is in effect, a constant current _and_ constant voltage charger.

Dave


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## tandem (Mar 13, 2011)

DM51 said:


> To those who ask how it is possible for someone to run a country and still find time to try and sound knowledgeable about battery charging, my usual response is "It is not easy at all."


 
LOL! 

We should all be pleased to see the current Prime Minister of the United Kingdom, David Cameron, stop in to chat about a cheap sub-optimal charger. Who knew?!


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## DM51 (Mar 13, 2011)

tandem said:


> LOL!
> 
> We should all be pleased to see the current Prime Minister of the United Kingdom, David Cameron, stop in to chat about a cheap sub-optimal charger. Who knew?!


In fact, this sort of thing happens quite frequently.


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## ElectronGuru (Mar 14, 2011)

15miki15 said:


> Is WF-139 charging method good? Or it is destroying faster that "classic" method lowering current (no CC/CV)?


 
There's a table somewhere showing a list of different max charge voltages and their corresponding lifespans (number of charges). Lower the top voltage -> less stress on the cell -> more charges before the cell declines. More time before the cells need replacement.

I think of CC vs CC/CV the same way. CC/CV is more gentle, but costs more, so get the charger that corresponds with the value of your battery stash. If you have $35 in cells (a couple of 18500's), a $20 charger makes sense. Another $35 in x years, not a big deal. $180 worth of cells (10x 2900's) changes things a bit.


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## Alpinebully (Oct 24, 2012)

I just received an Ultrafire WF-139 Charger, bundled with a 2X Ultrafire BRC 18650 3000mAh and a new 2nd Generation Fenix TK35.

My brief testing of the WF-139 Charger ive received shows:

The Open Circuit / OC for the charger is 0 Volts. 

Installing moderately discharged batteries results in a charge of 0.330A being fed into the batteries. The voltage at completion is 4.17Volts.

It does not trickle charge at the end of charging and the LED indicators function as follows; Power On with no Cells installed = Solid Green. Discharged Cells installed = Red, blinks to Green every 1.5-2 seconds. After Charging has completed = Solid Green.


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## Alpinebully (Oct 24, 2012)

Sorry, just a little further information to add to my post above;

Im not sure about the CC/CV thing... not sure what my charger is doing. 

It seems like it is immediately going into a CC cycle. Install cell, current is constantly floating between 0.330-0.335A. The voltage simply slowly rises until the LED's go Solid Green. At which point the Cell voltage is 4.17V.

I havent been able to find much information online at all about this Open Circuit = 0V 'Generation' WF-139. The one and only reference i found to it, suggested it having a higher charge rate around 1-1.5Amps. Clearly mine does not.


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## razvan-l (Feb 1, 2013)

HELLO !
iam new here end i say hello to all mebers.
a received today a last version of a WF_139 , and the open circuit voltage is 4,25 volt
after complete test will post the measurement
sorry for my bad english
razvan
if you request i atach the foto with pcb


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