# greatest danger using li-ion cells occurs during re-charging



## cy (Apr 16, 2007)

unfortunately inherent dangers of using li-ion cells are not always apparent. cpf'ers are on bleeding edge of technology, using consumer grade loose li-ion cells. 

greatest danger using li-ion cells occurs during re-charging, not during use. most lights are constructed well enough to prevent dead shorts. use bare li-ion in series with extreme caution. protected li-ion cells are always preferred. 

some li-ion cells are indeed protected for high & low discharge. overcharge protection is where it's needed the most. Pila's contain overcharge protection. (According to AW all of his protected cells contain overcharge protection.)

if you are not going to invest in a hobby grade charger. safest li-ion cells to use is with overcharge protection. 

new Pila chargers will terminate charge at 4.2v. most low end chargers will trickle charge after light turns green. a trickle charge will eventually overcharge. 

li-ion cells have a narrow charge widow of 4.10v-4.20v, without a natural termination point. And will accept charge long as you feed current to cell. until thermal runaway is reached... rapid disassembly of cell (explosion) if other cells are close by (secondary explosions) possibly burning down your home. 

it's not possible to charge li-ion in series and stay balanced without individual leads going to each cell. This requires charger with multiple channels or balancer module. safest way to charge li-ion cells is in singles! multiple li-ion cells can be charged in parallel. make sure cells are within .5v of each other to prevent excessive currents as cells start to balance each other. charge rate should be set to 1c of lowest rated cell in stack. http://candlepowerforums.com/vb/showthread.php?t=161299

personally I would not use low end chargers. Invest in a good hobby charger. I use schulze and triton. lots of other choices. it may be worth reading balance cradle thread. http://candlepowerforums.com/vb/showthread.php?t=158121&highlight=explosion

it's a relatively new trend to use multiple li-ion cells to drive hotwires. li-ion cells when discharged in series at high rates will become unbalanced. there's evidence dentrites will form during slow charge after cell reaches 4.2v and during high discharge exceeding mfg recommendations. these sharp formations could cause an internal dead short. 

if you charge those same series of unbalanced cells. charger will charge up to correct voltage/termination point for number of cells. but internally some cells will be undercharged, some will be overcharged. if unbalance condition becomes bad enough you will reach thermal runaway (explosion). 

C & D sized li-ion cells have been available in limited numbers with little guidance of dangers during re-charging. accidents with C/D sized li-ion cells will not be minor events. (AW's C li-ion contain protection PCB)

The RC community has been using and recharging lithium polymer packs for sometime. there's been a number of explosions documented. mostly during recharging. http://www.rcgroups.com/batteries-and-chargers-129/

So far we have only one documented instance of a li-ion cell exploding on cpf. this was caused by operator error, selecting an incorrect setting on the charger. http://candlepowerforums.com/vb/showthread.php?t=152013&highlight=explosion
charger involved in this explosion caused by user error is http://candlepowerforums.com/vb/showthread.php?t=117653&highlight=norm
fortunately no one was injured and house didn't burn down. but results could have been much worst. 

it's extremely hard to cause a NMH battery to explode. VS it's relatively easy to cause a li-ion cell to explode by overcharging. 

until A123 type cells become available in sizes cpf'ers can use. it's my desire to raise awareness of inherent dangers of li-ion use and avoid series of explosions and fires RC community has experienced. 

apologies for length of post. I've tried my best to avoid technical mumbo jumbo....for more details http://candlepowerforums.com/vb/showthread.php?t=106242&highlight=explosion

If any information needs to be updated or corrected. please let me know and I will get it done. due to evolving nature of state of li-ion cells. this post is subject to revision. 

if I had to make a few recommendations for using li-ion cells:

DISCLAIMER/CAUTION: I am not a battery expert nor do I pretend to be one. Please verify this information for yourself. Use this at your own risk. Not responsible for anything. Information for consumer use of loose li-ion cells is constantly evolving.

1. recognize greatest danger of using li-ion cells occurs during re-charging. 
2. invest in a hobby grade charger and avoid use of low end chargers.
3. use li-ion cells with internal protection circuits (overcharge, over-discharge). especially when used in series. 
4. don't charge in series without balancer leads going to each cell. w/independent channel for each cell. 
5. safest way to use/charge li-ion cells is in singles. 
6. don't use li-ion cells in series without protection circuits.
7. beware of dead short dangers. li-ion cells discharge at high rates
8. never charge li-ion cells unattended
9. charge li-ion cells in a protected area, so if fire should occur. your home will not burn down.
10. discharge larger li-ion cells to 3.4v before shipping. this removes almost all stored energy in cell.


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## Josey (Apr 16, 2007)

Thanks for the information, Cy. I've been charging my AW Li-Ion C cells at 2 amps, which is the highest my Tenergy balanced charger can go. But that's the initial charging rate. The last three hours or so, the charge rate drops down slowly from 1 amp to 0.4 amp, when the signal to stop charging beeps. Since this charge rate is well below 1C, how much of an issue is it?


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## cy (Apr 16, 2007)

josey, that's normal... a good hobby li-ion charger will ramp up current (.1C) slowly until a set voltage is reached, then ramp to max current selected by user or charger. then at a set voltage charger will step down current to a low level until final voltage or 4.1 or 4.2v is reached. at that point charge will terminate. 

you can fast charge at 1C up to aprox. 90% of total capacity of cell, but then it will take longer to reach final termination point. or you can charge at .5C up to aprox. 90% slower, but then it's shorter to reach final termination point.



Josey said:


> Thanks for the information, Cy. I've been charging my AW Li-Ion C cells at 2 amps, which is the highest my Tenergy balanced charger can go. But that's the initial charging rate. The last three hours or so, the charge rate drops down slowly from 1 amp to 0.4 amp, when the signal to stop charging beeps. Since this charge rate is well below 1C, how much of an issue is it?


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## Led_Blind (Apr 16, 2007)

Josey said:


> Thanks for the information, Cy. I've been charging my AW Li-Ion C cells at 2 amps, which is the highest my Tenergy balanced charger can go. But that's the initial charging rate. The last three hours or so, the charge rate drops down slowly from 1 amp to 0.4 amp, when the signal to stop charging beeps. Since this charge rate is well below 1C, how much of an issue is it?



it is all about overcharging. If after the charge cycle has stopped 0.4a is still delivered to the cell then there is a definite chance of overcharging. Dont worry about the 2a, those C cells are almost double that in capacity.

I have blown a lipo, it puffed up like a ballon on a normal charge cycle. Got to full charge fine, flew the heli fine but after that it was recycled


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## cy (Apr 16, 2007)

cpf'ers are on bleeding edge of technology, using consumer grade loose li-ion cells.

until recently loose li-ion cells have not been available direct to consumers. most li-ion mfg still refuse to sell large loose li-ion cells to consumer. 

JSB was directly responsible for this trend by financing the original protected R123 li-ion cells. JSB suffered huge financial losses due to this. We owe a debt of gratitude to JSB and should try to support him by purchasing products from JSburleys. 

For the record Siverfox, Newbie and JS are the real experts of battery technologies. I've posted this information separate from first post due to length. there's so much information to cover... it's incredibly hard to be concise.

with C size li-ion cells available and used in series for hotwire applications. As these newbie users of li-ion cells attempt to re-charge these C li-ion cells in series without proper precautions. 

the safety issue has become acute!

direct sellers of larger sized li-ion cells are almost all from far east. which for all practical purposes sellers from far east have zero liabilities from accidents. If say someone's house was to burn down from a defective product. it would extremely difficult, if not impossible to hold those folks accountable.


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## balazer (Apr 16, 2007)

As far as I've read, the DSD charger is one inexpensive lithium ion charger that will not overcharge your cells.

If you use such a charger, are you really at any more risk than if you use any other lithium ion devices, like a cell phone or laptop? Those devices, too, have occasionally been shown to explode or start fires.


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## brightnorm (Apr 16, 2007)

Cy,


This is important information that should be seen by every CPF member. IMO it should be stickied, and not just in this forum.

Brightnorm


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## cy (Apr 16, 2007)

low end li-ion chargers are notoriously fickle on actual point ending charge. I've taken 5 separate nano chargers and ended up with 5 slightly different termination points. 4.12v to 4.3v

further all of the low end charger shown in pic didn't truly terminate, but continued to trickle charge after green light came on. New pila charger are among the few exceptions. 

a safe way to use low end chargers is recognize you cannot leave cell charging in cradle for long periods. charge attended and remove cell after light turns green. then quickly measure final charge a few cycles to determine actual voltage. 

if you want to experiment how quickly trickle charge builds up. simply leave cell in cradle for a set number of hours, then retest for voltage. don't allow cell to go above 4.20v

correct operating range for most li-ion cells is 4.10 - 4.20v range. look to your mfg for exact spec's. best choice if you charger gives one, is to charge to 4.1v termination. only charge to 4.2v when you need max capacity. 

low end chargers typically charge at aprox. 500 milliamps or less. note as li-ion cells sized go up, amount of current needed to charge at most mfg is .5C to 1C. smaller chargers simply cannot supply enough current to meet these needs. 

cell phone and laptop are usually UL approved devices and contain a host of protections built in. laptop battery packs comes with protection and most monitor cells in series of three. explosions are rare but do happen. as you know loads of recalls involving laptop batteries. 

part of the safety issue with using loose li-ion cells is directly related to the perception that it's safe to plug in a li-ion charge and forget about it. 

some li-ion cells and chargers sold contain little to no protection. for instance the explosion reported on cpf was caused by user error. charger in question contain no protection if user selected wrong voltage setting. http://candlepowerforums.com/vb/showthread.php?t=152013&highlight=explosion

so if you selected two cell setting and proceeded charge one cell. this would result in serious overcharging and likely explosion. there will be no warning... charger will simply overcharge cell(s). http://candlepowerforums.com/vb/showthread.php?t=117653&highlight=norm

you can do the same thing with hobby chargers too. it much harder for warnings will be issued several times by triton and schulze wrong chemistry is selected or wrong number of cell is selected etc. 

but fooling any charger can be done. you can cause a li-ion cell to blow up by chargering it at say NMH settings. 

note: you cannot safeguard against stupidity! It's no problems to safely use li-ion cells. once you realize the consequences of overcharging loose li-ion cells. 








balazer said:


> As far as I've read, the DSD charger is one inexpensive lithium ion charger that will not overcharge your cells.
> 
> If you use such a charger, are you really at any more risk than if you use any other lithium ion devices, like a cell phone or laptop? Those devices, too, have occasionally been shown to explode or start fires.


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## SilverFox (Apr 16, 2007)

Hello Cy,

The actual maximum voltage for Li-Ion cells is more precisely stated as 4.200 volts, plus or minus 0.05 volts.

I think it is better to target 4.200 volts and understand that there is a little room for error, than to target 4.25 volts and forget that the $10 volt meter being used may not be totally accurate.

I hope you can understand this subtle difference.

Tom


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## cy (Apr 16, 2007)

Tom, thanks for the correction and edited accordingly to 4.1v - 4.2v

the 4.15v to 4.25v range come from white papers, depending upon mfg. 

totally understand why it's much better to state 4.2v with a .5v room for error.


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## MrAl (Apr 16, 2007)

Hi there

I build all my chargers with a built in difference circuit that constantly monitors
the voltage and cuts back current more and more as the voltage gets closer
and closer to 4.2 volts. For example, at 4.100 volts the cell might get a full
1 amp of current (max for that cell) but at 4.190 it may only get 250ma and
at 4.199 volts it may only get 5ma. If the cell could ever really reach exactly
4.200000 volts it would get a theoretical zero amps of charge, effectively 
cutting it out altogether. If there is any little self discharge which brings the
cell down to 4.199999 volts for example then perhaps 1ua of current would
then begin to flow, but this isnt really strictly speaking a trickle charge because
it's not constant...it's directly related to the cells voltage and its internal
resistance. A true trickle charge could eventually cause an overcharge condition,
but be aware that some manufacturers *may* call a charge that is indeed related
to cell voltage (as with all my chargers) a trickle charge, when really it isnt.
To find out for sure i guess you would have to measure your charge current
when the cell is right up at 4.200 volts. If the charge current is extremely low
then it's ok...if it's still 50ma then it isnt ok to leave on charge.


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## SilverFox (Apr 16, 2007)

Hello Al,

I am afraid your set up is what is considered as trickle charging. 

When the cells are healthy, this should not present any problems, however as the cells age they will be subjected to a trickle charge for an extended period of time.

First, let's take a look at a typical specification sheet for ah Li-Ion cell. Here is one from Panasonic. Notice that in the charging reference they refer to a 50 mA cut off for these cells.

The range is from 0.2C to 0.5C for the cut off current. 

This means that when the current falls below the cut off value, the charge shuts off. The charger remains off until the voltage drops to around 4.05 volts. Then it starts up again, and once again completely stops when the current drops below the cut off current.

Back to the aged cell. The cell is considered "dead" when its capacity drops below 80% of its initial capacity. The reason the capacity drops is because the internal resistance of the cell goes up. This increase in internal resistance limits the maximum voltage of the cell. This means that it spends more time holding the constant 4.2 volt as the current tapers off. If your current never shuts off, you can effectively trickle charge it for quite a while as the cell struggles to stay at 4.2 volts. 

As soon as you remove the cell from the charger, the voltage will drop on a cell with increased internal resistance. Your cell may have been charged to 4.2 volts, but when you take it off of the charger it may drop down to 4.12 volts, or something like that.

The lithium metal plating occurs when the cell is at its highest potential and has a very slight charge continuing to go into it. When you review a typical charging curve, you should see about 1/3 of the time spent in the Constant Voltage phase, 1/3 of the time the current will be tapering off rapidly, and the final 1/3 of the time is a very slight taper off in current until the current shut off value is reached.

Aged cells respond to charging differently. They will have a reduced Constant Voltage phase, a similar taper phase, and a greatly extended "trickle" charge phase.  This is also what happens during charging at higher charge rates.

The extended amount of time spent during the last phase of charging is not healthy for the cell because it promotes the plating of lithium metal out of the electrolyte solution. This can also become a safety issue.

It just so happens that when cells are at 80% of their initial capacity, the third phase takes around 2 - 3 times longer to complete. This results in more time spent in this potentially "dangerous" zone.

Some of the hobby chargers have a fixed cut off of 100 mA. When the charge rate drops below 100 mA, the charge stops. Others use 0.05C of the charging current you select. You end up with slightly less charge, but avoid any issues of lithium plating. The other plus is that the charge time is reduced.

I would suggest that you add a charging current cut off to your charger.

Tom


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## 65535 (Apr 16, 2007)

Standard CC/CV charging in parallel banks IMHO is the best way to charge, you can set the desired voltage you want, lower voltage increases cell life expentancy. Also the charge terminates itself once the current trickles to nearly nothing the cell is charged, works great on LA batteries, and lithiums, of all types, a Good CC/CV transformer, coupled with both a current and voltage measuring device of high accuracy make one of the best chargers out there.


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## mdocod (Apr 16, 2007)

this is a great and informative thread. Thankyou!


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## jumpstat (Apr 17, 2007)

So what recommended for a highend li-on charger that have all that is required to safely charge and take care of batteries? For your info I use AW's protected cells and Tekin charger with direct charge mode at 250-350mA CC, overcharge handled by the battery circuit.


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## SilverFox (Apr 18, 2007)

Hello Jumpstat,

You need to start using a charger designed for Li-Ion cells.

Using a charger designed for NiCd cells and relying on the cells protection circuit to stop the charge is not recommended. A NiCd charger is capable of blowing the protection circuit on your cells.

The NiCd charger charges at a constant current and the voltage ends up where ever it does. The charge is terminated on a drop in the peak voltage.

A charger designed for Li-Ion cells uses a Constant Current to raise the voltage to 4.200 volts, then clamps the voltage at 4.200 volts while the current drops off. The charge is terminated when the current drops below around 50 mA, or 0.05 times the charge current. This is called Constant Current/ Constant Voltage charging. It is similar to what is used for lead acid batteries.

Pila has a very good charger that follows the CC/CV algorithm and it shuts the current off at the end of the charge. It is called the Pila IBC charger. Do not confuse the old style Pila chargers with the IBC one, the old ones were designed for the old style Pila cells only. The IBC Pila charger will charge all cells, protected and unprotected, safely.

Tom


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## LuxLuthor (Apr 18, 2007)

It is obvious that there are still an unknown number of people who have not yet heard about the dangers with Li-Ion charging. Once you hear about it and understand, then you can take the proper steps to ensure safety.

There are some that believe any of these threads talking about the explosions and fires that can happen relatively easily with Li-Ion charger is like Big Brother trying to shove something down everyone's throat. In reality, it is a thoughtful campaign to simply make people realize that charging Li-Ion cells is not like charging NiCad or NiMH.

Thanks for all the information in this thread.


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## petrev (Apr 18, 2007)

What Lux said - Info everyone should know

Thanks cy

Newish Thread

*Day to Day - DN/Tenergy4P, FMA-Cellpro/HD6S and Voltcraft Balanced Sys. Charging*


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## MrAl (Apr 18, 2007)

Hello Tom,



> Hello Al,
> I am afraid your set up is what is considered as trickle charging.


What is there to be afraid of 
As i said in my previous post, some people call it trickle charging
and some dont. You or anyone else can call it that if you like, and
that's fine.
I dont call it that because i dont call a charge algorithm that can
eventually reach near zero current trickle charging, although i 
dont think i ever let it get that far in actual use because i 
always take it off charge before long anyway. Proabably the longest
i have ever left a cell on charge like this was 24 hours.




> I would suggest that you add a charging current cut off to your charger.
> Tom


Well, in one of my chargers i built in a circuit to detect end of
charge at some low level like 50ma, but with my other charger it's
a matter of taking a circuit that works fine the way it is and
adding to it more parts and more board space. I would quickly do
this if i ever found it to be critical to the operation of the
unit, but for years now it has worked just the way it is and it
doesnt seem to bother the cells that i have been using.


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## SilverFox (Apr 18, 2007)

Hello Al,

I understand that you are pleased with your battery and charger performance, however the question still remains...

Why do the Li-Ion battery manufacturers specify a low current cut off at the end of the charge?

Tom


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## cy (Apr 18, 2007)

I've noticed as li-ion cells age, their ability to receive a full charge goes down. so a charger that keys on voltage alone will keep attempting to charge until set volt is reached. 

when you remove cell from charger after termination to end voltage. cell will quickly drop. 

just repeated this with a protected R123 cell charged to 4.1v and repeated to 4.2v. both instances cell dropped to 4.02 after removal.



SilverFox said:


> When the cells are healthy, this should not present any problems, however as the cells age they will be subjected to a trickle charge for an extended period of time. ~
> 
> Back to the aged cell. The cell is considered "dead" when its capacity drops below 80% of its initial capacity. The reason the capacity drops is because the internal resistance of the cell goes up. This increase in internal resistance limits the maximum voltage of the cell. This means that it spends more time holding the constant 4.2 volt as the current tapers off. If your current never shuts off, you can effectively trickle charge it for quite a while as the cell struggles to stay at 4.2 volts.
> 
> ...


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## MrAl (Apr 18, 2007)

Hi Tom,

That's a good question, and my best guess is that they simply seek to define what
is a fully charged cell and what is not. Not all specifications are there to protect
the product and by specifying some low charge current cutoff point they also
provide some reasonable length of time that they can call the "required charge time".
If it were not for that cutoff point (which is easier to measure by current level)
the charge time could be many hours, with the many hours after the cutoff point
contributing little to the total charge.
For example, it may take two hours to reach the low current cutoff point, but
another four hours to reach say 1ma. Would you rather say your product charged
in two hours or in six hours? This doesnt mean the cell is going to warp into another
dimension if it's charged for six hours, but it does give the manufacturer a nice
selling point which is competitive with other cells like it.
Another way of saying this is that if the little green LED lights up after 2 hours
most people will be more happy with their charger than if it takes 6 hours and
the last 4 hours of that time didnt do much.

There are other good examples of where the spec's are a bit misleading, and another
very good one is about charging this very kind of cell...
The spec says something like: "Charge with a constant current and then with
a constant voltage". The misleading part is the 'constant current' part because
a constant current is a current that is fixed at one specific level, and that level
does not change. In actual practice there is no reason why this current can not
change however, as long as it does not exceed a certain upper level. In this
case the upper level point is more critical but the better way to define this is to say
it is a "current limit" and not a "constant current". The main point is that
either way the cell gets charged and there is no damage to the cell, but the
selling point here is that with a constant current the cell does in fact charge
somewhat faster than with a current limit in some designs, although the difference
can be very small.
Designing a constant current can be much more costly than a current limit,
but then again even a current limit is a bit misleading, because it should
really read "approximate current limit", where the upper set point is 
roughly near the max for that cell (within maybe 20 percent or so).
Some people could even think that 'constant current' means
"precision constant current" or that "current limit" could mean
"precision current limit", where neither of these are correct.
Maybe it should read, "Charge with any dang current, just dont go
too high above the max spec, and then switch to voltage mode".
The only drawback would be if 'any dang current' was too low it 
would take much longer to finish the charge.

These are both examples of where the specification seems to take on more
meaning than it was originally intended to have. This is something like where
a parts tolerance is over specified, making a project much more costly than it 
should really be.

Of course some specs must be taken as exact and should not be changed,
such as the max voltage spec of 4.2 volts, which is allowed to go as
high as 4.25 volts but not any higher no matter what or damage can
be done to the cell.

We thus have to recognize these two different kinds of specifications
so we can design cost effective products that are also safe to run.


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## PhantomPhoton (Apr 19, 2007)

Is this the Pila IBC charger that you are talking about?

Pila IBC Charger

jsburlys seems to be the only place selling it on my list of flashlight bookmarks. Feel free to add in more places that offer it but this one was the only one I could find without significant hassle.


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## Led-Ed (Apr 19, 2007)

That's the one, Phantom.Great charger that I use for all my Li-ion cells.


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## LuxLuthor (Apr 19, 2007)

The Pila 2 slot charger is well designed, but limited by its 600 mA per slot charging rate which takes a long time. I think the next best charger is the DN/Tenergy setup with AC power adapter, but you still need to get the Voltcraft cradle sent from Europe and modify it. Beyond that you are into the Triton, Schultze, Hyperion, or other brand of Hobby chargers & balancers...but still need the cradle.


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## cy (Apr 19, 2007)

yes this is the correct model, but please note this is not valid for early Pila chargers. which were completely different. 

early pila chargers were dumb chargers and contained no termination electronics. they depended completely on pila cell to terminate charge. charger puts out aprox. 4.8v. 

it's amazing how many different versions of loose li-ion cells and li-ion chargers that's been available through cpf sellers for the last two years. 









PhantomPhoton said:


> Is this the Pila IBC charger that you are talking about?
> 
> Pila IBC Charger
> 
> jsburlys seems to be the only place selling it on my list of flashlight bookmarks. Feel free to add in more places that offer it but this one was the only one I could find without significant hassle.


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## Phredd (Apr 19, 2007)

cy said:


> 1. recognize greatest danger of using li-ion cells occurs during re-charging.
> 2. invest in a hobby grade charger and avoid use of low end chargers.
> 3. use li-ion cells with overcharge protection if you are not going to invest in a hobby grade charger.
> 4. don't charge in series without balancer leads going to each cell.
> ...



Is #7, "don't over-discharge"?

I'm new to unprotected lithiums. My first Orb is in the mail. I thought the most danger was in over-discharging, because then the cell could explode during charging.

Phredd


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## cy (Apr 19, 2007)

many thanks for pointing out #7 is missing. shows how difficult editing you own writings is. 

#7. be aware of dead short dangers. li-ion cells can discharge at high rates. 

this includes dead short dangers while handling cells. check to make sure there will be no internal dead shorts. positive nipples on li-ion veri widely in width and height. 

if you discharge a bare li-ion cells below 3v internal damage may occur. discharging below 3v is not dangerous, but will damage li-ion cell. 

firefly and other lights that uses a metal clip to hold sammie in. larger nipple of R123 could cause a dead short. 

HD45 is designed for 18650 and/or 2x CR123 primary cells. combine extra width for 18650 with kilroy spring and extra wide nipple of smaller diameter R123 could bridge center contact with kilroy spring. note if you put 2x R123 in HD45 you will kill board. 



Phredd said:


> Is #7, "don't over-discharge"?
> 
> I'm new to unprotected lithiums. My first Orb is in the mail. I thought the most danger was in over-discharging, because then the cell could explode during charging.
> 
> Phredd


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## hburner (Apr 30, 2007)

Great thread and very imformative cy.

I never divulged this bit of information, mainly becaue I knew it was my fault.

I had 2 17500 cells that I was using in series my C3. They where freshly charged and placed in the light the night before. The next day I had to go in early and was going to use my C3 (surefire) becuase the maintenence guys always shut off the lights when I go in on Sunday mornings by myself it is dark as crap in there(me and the plant manager).

Anyway, prior to leaving the house I turned on the C3 and nothing. Dead. This was beyond me at the moment. So I just grabbed my L5 and went out the door. 

When I got back home I tested each cell. 1 cell was at 4.0v and the other was 0.00. ZERO? how in the heck did that happen? I still do not know. Like a complete idiot, I knew better but was hard headed and going to try anyway to recharge this cell. My MAHA would not start a charge on it. So I switched it another voltage sensitive charger and it would not charge it either. So I put it in serises charge with the other cell and after checking it about an hour later it had a charge of about 3.0v

I thought I can save this thing. I went into the living room and left it charging in series with the other battery, fell asleep and was awakend by a .410 gun shot going off in the back bedroom and my wife screaming somethings on fire.

Sure enough when I got back there the one cell had exploded and was cherry red and parts of it were going thru my computer desk, printer, and external burner. Luckily none of it got on the carpet. I put water on the red parts of it and cleand up the black crap that had gotten everywhere within 3 feet.

Just a little story to add cy's very important message, signed, anonymous.


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## cy (Apr 30, 2007)

Yeooooo.... glad your house didn't catch on fire and most importantly no one got hurt!!!

operator error or course, but which charger did you use to set it off? 
and at what setting? 

what brand 17500 cell and was it a protected cell? 
got any pictures? 

this makes the second documented li-ion explosion posted on CPF. 

DISCLAIMER/CAUTION: I am not a battery expert nor do I pretend to be one. Please verify this information for yourself. Use this at your own risk. Not responsible for anything. Information for consumer use of loose li-ion cells is constantly evolving.



hburner said:


> Great thread and very imformative cy.
> 
> I never divulged this bit of information, mainly becaue I knew it was my fault.
> 
> ...


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## VidPro (Apr 30, 2007)

its funny how you say you wouldnt use a cheap charger, kinda suggesting that normal people need to plunk down $100 for a charger, with some cute brand name, and complex capacity to do things.
yet when they blow up the cells in TESTING, what do you think they use ? A High amperage hobby charger.

because these overpriced chargers need a expert practicaly to operate them Correctally, and CAN exceed the specs for a cell, mabey a expert would want to use them, but there is no need for the consumer to try and charge FASTER to be safer.

lots of these cells are tested to 5V <--- yup WAY over, to see if they will start a fire, and they do not, untill you increase the AMPerage too.

while telling people to avoid cheap chargers, that go OVER spec when charging, is a good idea. The TOO high ones need to be identified, but the current on a cheap charger is so low, that catastrofic failure is LESS likly than a improperly used FAST charger.

if people aint gonna plunk down the cash , and time , and read manuels, they are better off with a LOW amp rate, then a High amp rate charger.
look at the specs for the Caused Fires, they are always pumping in some major juice.

ID the junk, and stop the sale of it alltoghether, its not good enough to say "pull it when its green" , it should be the thing sucks send it back, dont use it.

there are a lot of good SLOW chargers, and the day you see people setting them up out back to blow up batteries, you can convince others that they will. 
Wheras the high end hobby chargers Misused are what you CAN/DO start a fire with.

we need good chargers, consumers dont need FAST chargers, nothing good will come of that, and proof of that is What exactally were each Fire causing event using? High end RC fast chargers, and fast high amp laptop chargers.

if i was staging a fire event, the last thing i would use is a nano.
ID the junk , but dont increase the rate.


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## LuxLuthor (May 1, 2007)

VidPro, you make some good points...and I agree with most everything you say. However, in reality there has not been much use or testing of the type of Li-Ion cells we are using from AW over a long time, and in larger diverse applications, chargers, and with the kind of sample size you have in the RC community with LiPo's. I don't know how long AW has been selling his Li-Ion's here, but as the cells age, there may be more problems develop with them.

I think it is very reasonable that it would be the "Hobby Chargers" that have the higher amperage which would be more likely to cause problems, but we really don't know how much of the Li-Ion problems will be related to those stronger chargers. I don't expect to see as many disasters with the Li-Ion cell users not being as likely to push their cells as compared to the RC users with LiPo, but it is fair to extrapolate with their experiences.

I suspect there are a few others who had this type of "clandestine explosion" like hburner posted...and just don't want to talk about it. We don't know what his charger setup was but it seemed to be something from MAHA and some other charger or two. It would be nice to get more specifics so we know what was used.

In the case of Norm's exploding Li-Ion cell post here, remember he only was charging a single 14500 cell with the Alin universal Lithium charger set on "2 cells" and *that charger only outputs 500 mA*, so it is not necessarily a high amp charging issue. The new example is apparently combined with a questionable/defective cell....but I'm guessing he was using a low amp charger.

The problem is whether people will know they have a defective cell, and then how it then behaves with even a low current charger.


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## SilverFox (May 1, 2007)

Hello VidPro,

Here is the reason people move up to more powerful chargers for Li-Ion cells...

To keep track of things, you need to attend to your charge. A good charge rate is around 0.5C - 0.7C. The maximum charge rate is 1C. At 1C it usually takes an hour and a half or two hours to complete the charge. At 0.5C, this time is extended.

Some people have lots of time and can attend to their charging all day while charging at low rates. Others, prefer to spend a couple to three hours charging, then they have other things they want to do.

I am charging an 11.6 Ah Li-Ion battery right now. Charging at 10 amps means that the charge will be finished before I am ready to go to bed. If I were charging at 500 mA, it would take around 32 hours. I am not staying up that long to baby sit the charge.

Now, when I go to charge my 330 mAh or 600 mAh cells, I set things up a lot differently, and charge at lower rates. It is nice to have the capability to also charge large batteries when you need to.

I think the problem is that people jump on the Li-Ion bandwagon without thinking the whole thing through. People are interested in a lightweight light that is very bright and that draws them in. All of the sudden they have a light that is using Li-Ion cells, now they have to figure out how to recharge those cells.

I believe this is what LuxLuthor ran into. Fortunately, he is taking the time to learn about Li-Ion chemistry and is proceeding cautiously while he is figuring things out. 

Slow charging has its place, but it isn't a universal answer. 

Tom


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## cy (May 1, 2007)

most may not realize it, but we on CPF are on the bleeding edge of consumer use of loose li-ion cells. 

information concerning safe use of loose li-ion cells is still constantly evolving. 

I'm not a battery expert, nor do I pretend to be one. but I do know who the battery experts are. IMHO Silverfox, Newbie and JS are some of the most knowledgeable folks around. 

due to the bewildering combinations possible with loose consumer li-ion cells and chargers. safety with li-ion cell use has to start at the cell level. 

Meaning protection needs to be at cell level in the form of built-in overcharge protection for loose consumer li-ion cells. 

loose bare li-ion cells are originally meant for professional battery pack builders who will place protection circuits in final product. 

when you purchase loose li-ion cells from US companies. typically requires signing off of safety disclaimers. here's one Tenergy uses http://www.all-battery.com/datasheet/TenergyProductSafetyandUsageAgreement.pdf

VS overseas li-ion suppliers require no such disclaimers. for all practical purposes, they operate without liability for possible accidents. 

this is a good thread for information about DSD and new Pila chargers. https://www.candlepowerforums.com/threads/130249&page=1&pp=20

can you pick out 14500 li-ion cells from identical looking AA NMH cells?


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## VidPro (May 1, 2007)

LuxLuthor said:


> In the case of Norm's exploding Li-Ion cell post here, remember he only was charging a single 14500 cell with the Alin universal Lithium charger set on "2 cells" and *that charger only outputs 500 mA*, so it is not necessarily a high amp charging issue. The new example is apparently combined with a questionable/defective cell....but I'm guessing he was using a low amp charger.
> 
> The problem is whether people will know they have a defective cell, and then how it then behaves with even a low current charger.


 
it might put out 500ma, but then it was at 7.2V, and it probably had a much higher voltage differential than intended, and might have pushed more like 750 or 1000ma.
but indeed that is a good example. doesnt relate to trashing a little weasily nano charger that ONLY charges to a max of ~4.2, and would not have that problem. those types of chargers wont even go to 36V at 4amps 

I have charged "defective" cells for DAYS, and DAYS, with them heating up, at .4-.5C rates, and they heat up. this particular set of cells was trash from age, and deep discharge, and was heating up, but keeping the rate low, i could not get multiple cells to even open up, let alone fire.


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## VidPro (May 1, 2007)

SilverFox said:


> Hello VidPro,
> 
> I am charging an 11.6 Ah Li-Ion battery right now. Charging at 10 amps means that the charge will be finished before I am ready to go to bed. If I were charging at 500 mA, it would take around 32 hours. I am not staying up that long to baby sit the charge.
> 
> ...


 
in the same sence while i was slow charging HUGE D cells with no problems for weeks on end and now for years, the first time i handed it to a "shultz/triton" user they slammed 1C into it and had a massive fire in "a few minutes" (thier words).

it isnt a universal answer at all, experts , and people who Learn everything they need to know, indeed SHOULD be using a great charger like that. but from what we have seen, the average person and the person having a lot of FUN  can have more problems fast.

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

reguardless , its like this with everything, sombody plunks down 250$ for a light, a charger, a car, some knife, some cool gadget, and EVERYONE should do the same thing. so just for the practicality of plunking down 250$ everytime somone on a forum thinks its the "best thing in the world", WHEN its great for experts, and people in the know, and people with to much money.

its not a reason to trash every other item out there that costs 1/12th that and can do the job.
meaning my 1litre car , would never pass the muster at a monster truck convention, but it still leagally does what any car can do, and it aint got a scratch on it 

there are some people who overclock thier 2500Mgz Cpu to 5400Mgz, dance all over the forum telling how wonderfull it is. but the rest of the people following thier advice, tried to return thier fried $200 processor .

sometimes experts forget how much time and effort and thought went into thier knowlege, and how dum the rest of us can be.


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## VidPro (May 1, 2007)

take another example, just for the sake of examples.
people had been charging ni-mhys for some 20 years, then along comes the "best charger in the world" those 900 and 9000 untested digital masterpieces. plunking down huge sums, charging at high rates. suddenly things are melting .
set these digital items incorrectally, or use them evil crap batteries that everyone in the world owns, and it Could be a bigger problem, than the "crudiest charger in the world".

i am not saying that ANY of it is "bad" , but that "improvements" often have as many ramifications, as the old stuff. so recommendations for moving way up in a world that you dont yet understand, are not going to "solve" problems by themselves.

one more point to the side, wasn't it high end RC chargers that were doing SEIRES charging without balancing? if these companies and thier chargers were so great of items, why did it take them so long to get balancing taps?
To compare what THEY DID, to your simple little parellel non-series charger, is crasy, it was thier seires charing without balancing, by those brand name chargers that caused loads of the problems that everyone gets all worried about.
ok Charring, charging , same differerance  you get the idea.


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## uk_caver (May 1, 2007)

VidPro said:


> in the same sence while i was slow charging HUGE D cells with no problems for weeks on end and now for years, the first time i handed it to a "shultz/triton" user they slammed 1C into it and had a massive fire in "a few minutes" (thier words).



I was thinking about what various people have written regarding overcharging, and was wondering if it's possible that extended low-rate overcharging might well not be enough to blow a cell, but could put a cell in a state where it was then particularly vulnerable to high-rate charging it might normally not have problems with?


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## VidPro (May 1, 2007)

uk_caver said:


> I was thinking about what various people have written regarding overcharging, and was wondering if it's possible that extended low-rate overcharging might well not be enough to blow a cell, but could put a cell in a state where it was then particularly vulnerable to high-rate charging it might normally not have problems with?


 
overcharging CAN indeed cause the same issues that over-discharging can, set the cell up for overheating when its charged.
overcharging even very very slowly, for a Long time will puff a li-poly, or open up a cell.

but most of the junk china slow rate chargers were Not going over 4.25, ever, green light or not. some are based on cheap protection curcuits.
and really ALL the batteries should have thier OWN protection, reguardless.

they wouldnt even SELL me cells , long ago, untill i defined what type of protection i would use on them. Seperated unprotected cells are for pack replacments, and pack making, packs that would have not only protection but thermal disconnect of some sort.
but heck protection curcuits are 2$ what was the problem? other than hotwires 

if some of them are going +-.05v of 4.20, then they are still in spec, if they are going to 4.35v, then we should be saying "Dont Use it" if its a problem. we know of one that people claim that is what it does, can we call a hoe a hoe?

besides who puts the name "FIRE" on a li-ion battery or charger anyways  thats just asking for it.


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## ckthorp (May 6, 2007)

Phredd said:


> Is #7, "don't over-discharge"?


I think #11 should be Phredd's "don't over-discharge". Hburner's story is a good reminder of that. See Tom's info here: http://candlepowerforums.com/vb/showthread.php?p=1990837#post1990837


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## cy (May 6, 2007)

many thanks for posting that excellent link! 

it's also covered under 
#6. don't use li-ion cells in series without protection circuits. 
#3. use li-ion cells with internal protection circuits

there's so many different gotchas with li-ion usage. it's extremely difficult to point all of them out without information overload! 

due to myriad of combinations possible with loose cells, lights/packs without protection circuits cells goes into and all the different chargers available. protection for loose li-ion cells is best at cell level. this safeguards against dangerous combinations. 

unfortunately hotwires can draw current in excess of 3C. 
internal protection PCB in cells see this as a dead short. 

soft start circuits, double clicking, larger number of cells in series, larger cells with higher current ratings, pilas ($18ea) and using bare cells are some of possible solutions being explored. 

safest use of li-ion cell is in singles. this includes picking a light that uses one cell and re-charging in singles. 

if you are using bare li-ion cells... yank cell at first sign of dimming. immediately measure cell voltage for first few uses to establish if over discharge is occurring. for all practical purposes, cells is empty under 3.5V. your goal is to yank cell before it goes below 3.5V. 

cells can recover if exposed briefly below 3V. damage can occur with ONE overdischarge. which will not show until you try to recharge cell. 

there's evidence dentrites can form during discharge at higher currents than mfg spec's and during extended charging at low charge rates. most mfg recommend .5C to 1C charge rates. 

dentrites form as sharp crystals which can pierce internals, leading to dead shorts. which will not show up until cell is fully charged. 



ckthorp said:


> I think #11 should be Phredd's "don't over-discharge". Hburner's story is a good reminder of that. See Tom's info here: http://candlepowerforums.com/vb/showthread.php?p=1990837#post1990837


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## LuxLuthor (May 6, 2007)

More good information. I think cy is right about us being on the bleeding edge of loose Li-Ion cell use. Scary thought. I think the best answer is the Saphion technology being used in more common loose cell sizes.

I think you should make #11 "Do Not solder the contact ends of Li-Ion cells." If Li-Ion packs are desired, only apply solder to the manufacturer welded contact strips, keeping heat away from contact terminals.


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## ckthorp (May 6, 2007)

Could always build one of these instead of soldering: http://www.philpem.me.uk/elec/welder/


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## LuxLuthor (May 6, 2007)

ckthorp said:


> Could always build one of these instead of soldering: http://www.philpem.me.uk/elec/welder/



LOL...yeah right, just what we all need to be experimenting with....on top of using Li-Ion loose cells, and in series, now we should try making a "Mr. Wizard - Li-Ion contact welder." God help us.


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## CDI (May 8, 2007)

Just a thought - what about making a housing for a Li-Ion charger so that any explosion/fire is confined so that it does minimal damage? 

This could be as simple as sitting your charger in a .50 ammo can, and place the charger on a firebrick. No lid, of course....but a kB/meltdown would probably be well contained in the can.


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## cy (May 8, 2007)

already discussed and covered many time on RC forums. 

do a google on lipo bag.. they also make a ceramic charge pot. these mostly contain, but sometimes not... fumes are not contained. 

a fireplace insert with steel doors may be one of the best spots to do charging. it'd contain any fire and vent too. 



CDI said:


> Just a thought - what about making a housing for a Li-Ion charger so that any explosion/fire is confined so that it does minimal damage?
> 
> This could be as simple as sitting your charger in a .50 ammo can, and place the charger on a firebrick. No lid, of course....but a kB/meltdown would probably be well contained in the can.


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## LuxLuthor (May 9, 2007)

I do all my Lithium charging now in the garage with concrete floor, or fireplace, or outside if warm enough. The toxic fumes are a concern that the various enclosures & Lipo Bag don't address alone.


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## SilverFox (May 9, 2007)

Hello LuxLuthor,

This might be a good time to discuss cold temperature Li-Ion charging.

Li-Ion cells should not be charged at ambient temperatures of 32 F or below. There is some concern that there may be some issues at ambient temperatures below 50 F.

I am not sure what the temperature is in your garage, but if it drops below 50 F, you may want to rethink your charging procedure.

Fred Marks at www.fmadirect.com limits the maximum voltage on Li-Po batteries to 4.1 volts per cell when the temperature is cool. He claims that the normal 4.2 volt charge can damage cells when the temperature drops. 

I have not done any testing on this, so I can not directly comment on it. Fred does a lot of testing, and is a trusted resource.

I believe the damage is similar to slightly overcharge cells. You loose cycle life. I don't believe this causes a rapid vent with flame incident.

Tom


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## wptski (May 9, 2007)

Well, kind of hard to contain the fumes or gas because you'd be containing the pressure too. If something like the Battery Bunker that can contain the explosion but if you made it airtight too, it would explode in a million pieces. How do you vent pressure without vent the toxic fumes??


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## ckthorp (May 9, 2007)

wptski said:


> How do you vent pressure without vent the toxic fumes??


Could you build a stiff but slightly stretchy enclosure (to reduce the peak pressure) and then just use a couple/three of those P100+organic+chlorine respirator filter canisters that they sell at the hardware store to filter the exiting fumes? What kind of volumes are we talking about here (I've never personally witnessed a vent-with-flames incident)? What kind of pressure profile is there? During unenclosed charging, is it typically "*boom* and done" or more of a half second/few seconds flaming+hissing kind of event?


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## wptski (May 9, 2007)

Yeah! Go ahead and build one then. Stiff but stretchy material? What would that be?? There is a rather long thread here with video/audio of 123 lithium explosions/fires to view.


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## ckthorp (May 9, 2007)

You don't consider something like heavy rubber to be stiff but stretchy which provides compliance but is much less likely to have a hole burn through it by a stray small piece of debris? Why the sarcasm?

I've watched a few videos now. It seems like *boom* is restricted to enclosed cells (though I haven't seen any videos of that). The unenclosed cell videos that I've now watched seem to be a fairly prolonged burning process. The LiPoSack people even set one off inside of a glass fish tank with weighted down cardboard on the top. So there really isn't much of a shockwave, just reasonable gaseous volume produced on the seconds order-of-magnitude time scale.

The way I see it, a battery charging safe needs to have a number of attributes. These include: non-flammable construction, power inlet for charging leads, volume compliance in order to absorb the gas produced by a rupturing battery, and either a lot of volume to hold the entire gaseous output or an output filter to reduce the concentration of output fumes.

There was a spark-and-flame filter I built for some model rocket parachute ejection tests. That filter was to stop the sparks and flame produced by burning black powder. It was essentially a wad of very coarse steel wool inside of a PVC pipe which stopped flaming particles from burning the 'chute. A similar device could be used to connect a sealed charging enclosure to a weatherbaloon.

What battery can I use to test such a device with, as cheaply as possible? I assume people are testing with batteries near their end-of-life?


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## LuxLuthor (May 9, 2007)

ck, I didn't think wptski's comment had sarcasm in it....just questioning what could there be that would be stiff but stretchable.

The problem I see with anything rubber or flexible is the flames/heat which would melt & catch it on fire....which is why the Lipo Sack was more of a non-flammable cloth fiber type thing. Don't know if they used a Kevlar type fabric...but must have been something like that....and which doesn't control the smoke/fumes.

It seems you would need an industrial type ventilation fan to contain the amount of smoke I have seen in several videos, including this one at PC PitStop with the computer battery pack. I believe those were individual Li-Ion cells similar to what we use....I doubt they used LiPo for those batteries.

There is actually a very good read by the guys that did that video at PC Pitstop here. The guy they are interviewing was the VP of Engineering at Gateway, and he covers a lot of good points.

I don't know of anyone who has done an intentional blow up of individual Li-Ion cells to see if they sometimes smoke/fire like the lipo's. We never heard back from that person posting the second example (besides Norm's example) as to more details of what happened.


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## ckthorp (May 9, 2007)

Ok. If no sarcasm was intended, I apologize. Regardless, I think that the spark and flame arrestor I used with my rocket ejection device could actually work well in this application. I'm going to give it a shot when I have time.


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## ckthorp (May 9, 2007)

Here's some good info on CR2 and CR123 battery gas volume output. http://www.fire.tc.faa.gov/pdf/04-26.pdf It indicates that in a 10-cubic-meter air-tight chamber, the pressure increase caused by 16 burning CR2 batteries, ignited via a firepan underneath, was about 2psi. The temperature rise was about 15 deg F. So I believe that we are dealing with volumes which could reasonably be contained.


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## LuxLuthor (May 10, 2007)

ckthorp said:


> Here's some good info on CR2 and CR123 battery gas volume output. http://www.fire.tc.faa.gov/pdf/04-26.pdf It indicates that in a 10-cubic-meter air-tight chamber, the pressure increase caused by 16 burning CR2 batteries, ignited via a firepan underneath, was about 2psi. The temperature rise was about 15 deg F. So I believe that we are dealing with volumes which could reasonably be contained.


I don't think I read the same report as you....or I have a different understanding of some of the information. 

I do not remember my physics enough to figure out the various effects of Charles Law, Boyles Law, etc....but this result of 2.6 psi increase in pressure from exploding 16 CR2 cells inside of a 10 cubic meter (or 33 cubic foot) chamber would translate to a much higher pressure when contained in a smaller volume box that a person would use for battery charging.

I am not sure how their ignition with a container of alcohol with that heat, flames, consumption of oxygen maps onto our battery charging scenario.

They were not able to produce a Lithium fire/explosion with their one laptop battery pack with their technique of heating them over alcohol. The PC PitStop video uses the more typical overcharging voltage technique, and it sure looks in this video like a much more dramatic pressure, temperature, and explosive damage outcome than this DOT test describes. So we have no idea what if any effect may be produced by a rechargeable cell triggered with overcharging voltage in an oxygen rich container...but something is not making sense here.

They really only used small disposable Lithium CR2 & 123A cells, so I'm not sure how that chemistry compares to what we are doing, but my reading of this pdf talks about an increase of 650° F in a 64 cubic foot chamber with vents and using alcohol to trigger.


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## ckthorp (May 10, 2007)

LuxLuthor said:


> I don't think I read the same report as you....or I have a different understanding of some of the information.
> 
> I do not remember my physics enough to figure out the various effects of Charles Law, Boyles Law, etc....but this result of 2.6 psi increase in pressure from exploding 16 CR2 cells inside of a 10 cubic meter (or 33 cubic foot) chamber would translate to a much higher pressure when contained in a smaller volume box that a person would use for battery charging.
> 
> ...


Ah, that's what the weather baloon was for. It's the space for the extra volume. I've got one on order. They're reasonably priced and have plenty more volume than a 10 cubic meter box.

I suspect burning the lithium is burning the lithium however the fire is started.

I suspect that on the FAA laptop battery, there was probably insufficient heat.

The 650 Deg. F increase was a peak temperature directly over the burning batteries, not an average temperature increase over the entire chamber. Also, the temperature testing chamber was only 64 cubic feet, or only about 2 cubic meters.

There were two different testing chambers. The first was a 64 cubic foot peak temperature, video filming, and airline cargo bag material testing chamber. The other one was a sealed 10 cubic meter chamber for testing the average temp increase as well as pressure increase from combustion byproducts. While only using small CR2 and CR123 batteries, 16 of them probably is more active mass than one 18650 cell. Anyway, I was just pointing it out as a reasonable baseline for exploding batteries, not that it was going to be 100% comparable to a rechargable fire.


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## LuxLuthor (May 10, 2007)

You looked at that video I linked, right? Good luck on this, I don't think anyone else is gonna try to put together all the elements you are talking about. I just use my fireplace or garage/outside if warm enough.


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## ckthorp (May 10, 2007)

Yup. I looked at the video. I think I'll still give it a shot. $40 for safe indoor charging really isn't that much expense.

Problem is, that in MN, there really isn't an alternative to indoor charging in the winter. The garage is certainly below freezing. The fireplace would be below freezing pretty quick after I opened the flue without a fire lit in it. That, or I'd be letting dollars worth of heat out, negating the main selling point of rechargable batteries -- reduced operating costs.

I'll start a new thread once I get things together. What's the cheapest way to start testing this rig? Tearing apart used laptop batteries from eBay?


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## wjb3 (May 10, 2007)

LuxLuthor said:


> but this result of 2.6 psi increase in pressure from exploding 16 CR2 cells inside of a 10 cubic meter (or 33 cubic foot) chamber would translate to a much higher pressure when contained in a smaller volume box that a person would use for battery charging.


 
Hi,
10 cubic meters is 353 cubic feet.
If you used a wood stove insert in your fireplace, it might be 28 inches x 18 inches x 22 inches (about 6.41667 cubic feet).
+2.6 psi x 353 cubit feet
= 6.41667 cubit feet x +143 psi
With +143 psi (or 10 atmospheres), you will need some serious seals and hinges if it was airtight.

-wjb3


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## SilverFox (May 10, 2007)

Hello Ckthorp,

In a cold garage, you can take an ice chest with a low wattage lamp in it and charge inside it. You may even be able to move the whole thing outside.

You are looking for a temperature in the 60 - 80 F range.

Tom


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## LuxLuthor (May 11, 2007)

SilverFox said:


> Hello Ckthorp,
> 
> In a cold garage, you can take an ice chest with a low wattage lamp in it and charge inside it. You may even be able to move the whole thing outside.
> 
> ...



Tom, I read what you said about the charging temperature, but this 20°F narrow range seems very unrealistic in general....so I'm wondering if it really needs to be this regulated. (I have not read anything on this yet).


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## SilverFox (May 11, 2007)

Hello LuxLuthor,

I was indicating an ideal target temperature range for charging. 

The "allowable" range is 32 F to 113 F, however there has been raised some concern with charging at temperatures below 50 F.

Tom


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## ckthorp (May 11, 2007)

Tom,

Thanks for the good info, as always!

-Chris


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## LuxLuthor (May 11, 2007)

SilverFox said:


> Hello LuxLuthor,
> 
> I was indicating an ideal target temperature range for charging.
> 
> ...



Tom, I was just looking at the instructions on a new Black & Decker 14.4V portable Li-Ion drill I bought yesterday, and it had these guidelines which reinforces what you said:*



Do NOT charge the batteries in an air temperature below 40°F or above 105°F. This is important and will prevent serious damage to the batteries. Longest life and best performance can be obtained if batteries are charged when air temperature is about 75°F.

Click to expand...

 *​


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## cy (Jul 8, 2007)

found it.. old links no longer works


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## LEDAdd1ct (Jul 18, 2007)

I've been reading this thread for the greater part of the last hour, and with an Ultrafire C2 and Tiablo A8 on the way, I am ready to buy my first 18650 charger. It seems that the Pila IBC is the best of the lot in the around U.S. $50 range. So, if I charge on my garage floor or on the driveway as a precaution...Here are some questions that have been on my mind:

1. Once the battery is charged and is sitting in my flashlight(s), do I have to worry about a spontaneous explosion? I mean, if I keep the light on my dresser next to my bed so I can use it at night, is the cell safe at rest?

2. With the Pila IBC, is the consensus that it will stop at 100% 4.2 volts with absolutely NO TRICKLE CHARGE whatsoever? This is probably the largest concern to me, and seems to be the "feature" (or in this case, lack thereof) that most other chargers lack.

3. What brand of 18650 protected cell in 2.2 aH capacity is most widely recommended? Is any protected Chinese cell okay, or is there a CPF favorite?

~Thank you!

LEDAdd1ct


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## DM51 (Jul 18, 2007)

LEDAdd1ct, using your question numbers:

1. Once charged as you describe, it is safe.

2. Correct. The Pila IBC charger cuts off correctly and there is no danger of trickle charge. That does not mean you can plug it in, load it up and leave it completely unattended, though - there are other causes of cells blowing up while recharging, as you will have read in this thread.

3. There are numerous opinions, but common consensus on CPF seems to be that AW, Wolf Eyes and Pila cells are the best brands. Cheap Chinese cells bought on eBay from random online dealers are asking for trouble.


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## LEDAdd1ct (Jul 18, 2007)

DM51, thank you very much for your succinct answers.

:thumbsup:

LEDAdd1ct


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## LEDAdd1ct (Aug 5, 2007)

I have since picked-up three AW protected 18650 cells, and one Pila IBC charger, and am really thrilled with both.

I have my Ultrafire C2 sitting on a shelf right now illuminating 2/3 of my bedroom as I type on my laptop, and the cells/charger work great!



LEDAdd1ct


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## LuxLuthor (Aug 6, 2007)

LEDAdd1ct said:


> I have since picked-up three AW protected 18650 cells, and one Pila IBC charger, and am really thrilled with both.
> 
> LEDAdd1ct



:thumbsup:


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## IgorT (Oct 26, 2007)

cy said:


> direct sellers of larger sized li-ion cells are almost all from far east. which for all practical purposes sellers from far east have zero liabilities from accidents. If say someone's house was to burn down from a defective product. it would extremely difficult, if not impossible to hold those folks accountable.


 
This is very true.

For example, i was considering becoming a retailer for a chinese helicopter manufacturer.

During the "negotiations" my sales man Sally kept repeating "single cell battery safer and not explode when charging".

When i asked if they EVER had ANY problems or accidents with two or more cell LiPos, (s)he just repeated the above statement.

Then i asked if they're batteries have protection circuitry onboard. (S)he said "yes it has protection and is safer and not explode when charging".

Then i took a cell apart and found only two wires connected directly into the cell. No small SMD elements.

Now i'm getting worried.. Who's gonna be held accountable if a customers house burns down....


BTW: The heli's electronics do shut down, when voltage is too low. The wall charger stops charging at 4.20V after an hour. But i'm still worried.


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## hank (Oct 26, 2007)

Who's going to be responsible? The family that bought the product are going to be out of luck, most likely. There's a case called "Daubert" that says the judge's personal opinion gets to decide what's allowed in evidence --- if the offered expert opinion is "scientific fact" --- and if not, like the local fire department's opinion on the battery charger fire below, the jury never gets to hear the case, it's thrown out.

Google something like: lawyers engineers "battery charger" house fire

You'll find ads lawyers like this one, they're real proud of their work.
Count on it, the battery charger is still out there in other people's homes.

http://www.milesstockbridge.com/PA/...12&PHPSESSID=8676d76df504ef19ff9ca83c461fc93c

"We represented The Black & Decker Corporation in a case that arose from a house fire that killed a grandmother and her one-year-old grandson. The plaintiffs’ expert witnesses claimed that a battery charger had caused the fire, and the local fire department agreed. The plaintiffs retained both a Ph.D. electrical engineer and an experienced fire origin and cause expert, and we conducted discovery designed to support a challenge under Daubert v. Merrill Dow Pharmaceuticals, Inc. Our Daubert challenge was successful, the Court struck the testimony of the plaintiffs’ expert witnesses and granted our motion for summary judgment. Knotts v. Black & Decker, Inc., 204 F.Supp. 2d 1029 (N.D. Ohio 2002). ...."

Just one example of many.


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## IgorT (Oct 26, 2007)

hank said:


> Who's going to be responsible?
> 
> You'll find ads lawyers like this one, they're real proud of their work.
> Count on it, the battery charger is still out there in other people's homes.
> ...


 
I don't live in the US. I'm from Slovenia, Europe.. So i don't know if that would work here..

I thought it would be obvious from my bad englisch that i'm not a native american speaker...  (if the pun doesn't work i blame it on the language barrier)


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## IgorT (Oct 30, 2007)

cy said:


> greatest danger using li-ion cells occurs during re-charging, not during use. most lights are constructed well enough to prevent dead shorts. use bare li-ion in series with extreme caution. protected li-ion cells are always preferred.


 
Hi cy!

Since you seem to know a lot about LiPos, i'd like to ask you a question..

For my laser i used a LiPo, that i scavanged from a broken helicopter..

It's a FullRiver 2 cell LiPo, but i wired it in parralel, cos i only need 3.6V and wanted more capacity..

I thought i would leave half of the protection circuitry attached, but it seems just the half doesn't work.. So i put a warning LED there, with built in circuitry, that warns me when the LiPo's voltage drops too low..

But today i had to charge it, so i did the following:

I set my lab PSU at 4.1V and limited the current to 130mA - 0.5C. It's a hobby grade LiPo and is usually charged at 2C...

I connected the PSU to the LiPo, and the current limiting immediately went into action. The PSU dropped the voltage to 3.4V, to compensate..

Then, as the LiPo was charging, the voltage slowly started raising, untill it got to 4.1V, then the current slowly started falling, untill it got to zero.

I measured everything, and set the PSU to 4.2V, and connected it again.
The same thing happened, only faster this time, and the current started dropping as the LiPo was starting to become fully charged..

The results i described are exactly what i expected to happen, and it seems to me, it is safe to charge it this way.. The LiPo didn't even get warm, unlike on the original charger..


What do you think of this? Are there any dangers here, that i'm not aware of?

I don't think so, since i'm being much (4x) gentler with the battery than the original charger was.. Any thoughts?


Thanks!

Igor


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## SilverFox (Oct 30, 2007)

Hello Igor,

Sounds like normal charging to me...

Charging in parallel is very safe, you don't have to worry about balancing the cells. About the only thing you have to watch for is damaged to the cells. If they puff up or drop below 80% of their initial capacity, its probably time to retire them.

Tom


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## cy (Dec 2, 2007)

here's an interesting chart showing characteristics of different types chemistry's. 
http://www.batteryuniversity.com/partone-3.htm

note chart showing li-ion as not tolerant to trickle charge.


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## VidPro (Dec 4, 2007)

cy , do you figure the reason they say " no trickle charge" is because you cant go over voltage, no mater HOW you go over voltage you cannot, the design of the li-ion doesnt allow for gas pressure of any sort from an overcharge. the other stuff copes with some levels of pressure or boiling off, without croaking

There in that data they did not say you couldn't Slowly come up to the max, trickle up to the 4.2v as opposed to rush up to it. 

they are more indicating that you cant shove 5v at some tiny (trickle) current , cause it will still die. unlike the other stuff, where you can keep topping off very slowly without it dying completly. ex 5v at 25ma with 3 ni-mhy wont DIE, li-ion will. Assumption you cant trickle, but does that stop you from slow topping?

in a few sony charge alogrythms , they fast charge to about 80% then they literally "trickle" thier way up to full charge using CV, the last little bit taking hours on end, just like the voltage control method does. if your just topping off the sony battery pack , it is also done at a slow trickle, just not a "trickle charge" by definition, more of a taper, because of the voltage.

there might be some need to stop at some slow trickle/float point anyways, as most of the stuff stops charging alltogether when the trickle is so slow. but i think in that chart they are saying that in COMPARISON, to the other chemestries and encasments which they CAN keep overcharging slowly, li-ion design is that it can never overcharge ever, so a (overvolt) trickle alogrythm cant be applied.

I have used the Volt MAX (4.2) tapering method that IGOR mentions sucessfully, for enough cycles and age to figure (for myself) that the low slow charge rate neer the end (which could be classed as trickle) is not a problem. i just dont use say 4.6V to do that  cause then it fails.


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## Rzr800 (Dec 21, 2007)

Can't thank cy and other fellow members enough up here for taking the time to educate us newbs on these issues.
Got up and charged my new AW18650's on my new WF-139 for the first time this morning. Spent a lot of time searching for the average amount of time this would take (didn't want to leave the charger unattended per all your good advice) and came up with everything between 4 to 12 hours.

To my surprise; I gave it a look in maybe an hour or a little better...both lights were green (let them sit for a bit and came up with somewhere between 4.1 and 4.2 volts).

Just wanted to voice my appreciation once again and remind folks of what I've obviously already been told...don't let that charger out of your sight in regards to these cells.


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## Rzr800 (Dec 21, 2007)

....with (I suppose) the follow up question being...is this fast charging time 'normal' for an 18650 fresh off of the factory floor?


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## SilverFox (Dec 21, 2007)

Hello Rzr,

Li-Ion cells are sold with some charge in them. Your first charge time should be quite a bit less that charging a fully discharged cell. However, if you frequently top your cells up, it could become normal.

Tom


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## Rzr800 (Dec 21, 2007)

Thanks for the reassurance, Tom. I went back over one of these threads for the umpteenth time and found a post of yours back in March where you cited 4 hours and 20 minutes for an 18650 top-off charge (85-90% depleted) so I don't know where I came up with those earlier charging times.
Again, it's really nice to be playing with fire here (so to speak) and receive genuine quality advice to calm your nerves a bit. Very much appreciated.

John


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## Dances with Flashlight (Dec 22, 2007)

Rzr800 said:


> Can't thank cy and other fellow members enough up here for taking the time to educate us newbs on these issues.



Ditto!


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## cy (Nov 2, 2008)

it's old news now... but cpf'er's were among the first folks in world to use loose li-ion cells. 

look at what JSB started with his seed $$$ investment in producing protected R123 cells. without that kick from JSB... we may still not be using loose (consumer) li-ion cells. 

don't forget the debt we owe to Newbie for his diligence in successfully duplicating CR123 venting with flame conditions.


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## LuxLuthor (Nov 3, 2008)

Just so I know who to appreciate, who is JSB ?

I really miss Newbie's contributions if that is him.


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## 4sevens (Nov 3, 2008)

LuxLuthor said:


> Just so I know who to appreciate, who is JSB ?
> I really miss Newbie's contributions if that is him.


No they are different entities. 

I miss both of them. Newbies been banished into never never land - actually
he resigned.

JSB is busy with his other ventures.

Both were and still are respected members of this community. :twothumbs

From Newbie I learned so much about led die fabrication and inductor choice and the technology thats going into them these days

From JSB I learned to treat customers right even at a loss and the results will be reaped over time. The free shipping idea is from him


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## SilverFox (Nov 3, 2008)

Hello LuxLuthor,

JSB is none other than Jon Burley...

Tom


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## cy (Nov 3, 2008)

waaaay back... long ago... or at least it seems that way. 

actually it was only a few years ago... Pila was the only game in town for loose li-ion cells. officially designed for Pila's own line of lights... pila cells made their way else where. 

CR123 have been with us for some time, but R123 cells have only been readily available for a short time only. 

JSB raised the seed capital for a chinese mfg to produce a protected R123 cell. the chinese of course took his ideas and investment and started producing R123 cells.... this R123 venture took most of JSB's life savings to pull off.... which he never recouped his investments. it was a pretty large sum $$$ for an individual to invest. 

the first R123 cell were pretty marginal... but from there... the dam broke! 

we on CPF were the principal initial buyers/users of loose consumer li-ion cells. guinea pigs if you will...

now days ... we don't give it a thought about using a loose protected li-ion cell. vs the old days... for a li-ion supplier even think about selling you loose li-ion cells... they'd required a disclaimer and proof you were going to mfg a pack with protection circuits.


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## WDG (Nov 4, 2008)

SilverFox said:


> The "allowable" range is 32 F to 113 F, however there has been raised some concern with charging at temperatures below 50 F.



Hi, Tom;

Could you elaborate on why this is? Does the cooler temperature make accidental overcharging more likely?

I've been loosely following lithium charge/discharge issues, but don't recall seeing this before. If one of the threads already goes into this in more detail, what would be the best search terms to get to it?

Thanks!


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## moldyoldy (Nov 4, 2008)

LEDAdd1ct said:


> I have since picked-up three AW protected 18650 cells, and one Pila IBC charger, and am really thrilled with both.
> 
> I have my Ultrafire C2 sitting on a shelf right now illuminating 2/3 of my bedroom as I type on my laptop, and the cells/charger work great!
> 
> ...



Wonderful! a like-spirited flashaholic! I normally work on my laptop with a backlight of an LED flashlight. I get ready for work in the morning mostly via flashlight. my wife thinks I am crazy. maybe I am per conventional electric consumption in the US.

Not to sidetrack this discussion, but, I lived in Germany for 3 years, and am well aware of what they do to limit electric consumption. If the US had their electric costs of Euro 0.20/KWH instead of maybe $0.08/KWH, the average US citizen would be shocked out of their indifference! Here in the US, I have driven my household electric consumption down to consistently about 150KWH per month, and last month it was 126KWH. That puts my single-story 1100 sq ft house with walk-out basement at about 2000KWH/year. The goal is 1500KWH/year, although that will be difficult! For that I would have to replace all fluorescents with LED "bulbs". Unfortunately, any LED system that comes close to 60 watts costs over $60. 

more to the thread subject, I am slowly switching back away from Li-Ion cells more because the Li-Ion technology is not ready for a plug-in and forget mentality that the Ni-Mh cells have reached. There are still far too many cases of incompatible cells and chargers, much less the inherent danger of lithium-something batteries. The Pila charger seems to be closer, but there was one thread identifying something like 4 different chemistries all using the name of Li-Ion. For the LEO, CR123 is the king, minus the ability of a Maglite to make a car window disappear quickly. For the average consumer, Ni-MH is the answer. The flashaholics and hobbyists are pushing the edge - and that is good. just remember that we are on the edge!


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## SilverFox (Nov 4, 2008)

Hello WDG,

At cooler temperatures, the lithium ions can plate out as lithium metal inside the cell. This results in an unstable cell, and greatly reduces the capacity available from the cell.

When lithium ions are plated out as lithium metal, the cell can "rapidly vent with flame" during discharge or during charging.

Tom


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## WDG (Nov 5, 2008)

Thanks, Tom. That sounds vaguely familiar, so it must be in one of the posts on them I've read in the past. Touchy little devils, ain't they?


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## LuxLuthor (Mar 8, 2009)

Pretty interesting to read back two years ago when cy started this thread. Man, that seems so long ago.


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## Turbo Guy (Mar 8, 2009)

I have used LiPoly batteries from 2 cell 360 mAh to 4S 3700 mAh charged at .7C throught 3C and discharges at up to 30C (12C average) for over 4 years and many thousands of charges and discharges. 

I have also used LiIon and LiFePO4. The LiFePO4 cells of choice for me are manufactured by A123 Systems and IMO are every bit as safe as Nicad or NiMH and in some respects are even safer. Quality LiFePO4 cells are also manufactured by K2 Energy Solutions. They are not quite as well suited to extremely high rate discharges or charges as the A123 Systems cells and do not last as well in such applications. The A123 Systems cellls are only available in two sizes. 18650 ,1100 mAh and 26650 ,2300 mAh capacity. K 2 has the 18650 in 1250 mAh capacity and the 26650 in 2500 and I believe 3300 mAh capacity.

I routinely charge the A123 Systems 1100 and 2300 capacity cells at 5C and take no more precautions with them than I do with NiMH AA cells.

On the other hand I use many safety precautions while charging LiPoly batteries, such as only batteries with balancing leads, balancing chargers, LiPolySack , constant monitoring.

Like Tom I use only high end hobby chargers. I need to know how many mAh, the voltage of the battey while being charged and at the end of charge. With LiPolys I need to know the voltage of each cell throught out the charge and how much inbalance (voltage difference) there is. All of my hobby chargers will terminate the charge if the inbalance becomes to great or any cell exceeds 4.235 volts. Several of my chargers also provide battery / cell IR reading which lets me keep close tabs on the cells health.

Hi,LuxLuthor


Charles


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## wayne21 (Apr 2, 2009)

Have you ever seen a battery explode ? an 18650 or a c size lithium ion cell, will the explosion be strong enough to hurt someone? bad enough to loose a finger or what ever.. I like to know all about the explosive properties of any chemicals or items I am working with. Knowledge can stop problems before they start. also knowing the strenght of an explosive will give you a good enough out look to make a safe container to do your charging in, but it has to be strong enough to contain it ,or it could add to the power of the explosive force. I would like to hear your thoughts on this. thank you for your time . wayne Farrar P.S You can reach me , if you will reply at {[email protected]} this way I will not miss your reply if you send one. I have personally seen many explosions, one blew my cousins hand off when we were 16 years old. I told him not to use the mixture he used for a rocket ,but he did not take my advice, and payed dearley.


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## baterija (Apr 2, 2009)

wayne21 said:


> Have you ever seen a battery explode ?



You can see one burn from overcharging here.


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## Patriot (Apr 2, 2009)

Li-po's are pretty wicked when they fail for whatever reason. A guy who I was flying RC with at the park recently had a speed controller failure which caused his plane to crash. Upon crashing the 3S 2600mAh li-po burst into flames. The wind was pretty strong that day so it was a scramble to run out and stomp out the flames. We eventually had to put out the battery fire with a 44oz water since it wasn't going out on it's own. The plane was completely burnt to a crisp and was a total loss...about $400 bucks worth.

I'm flying one plane with a 6S 6000mAh and I'd hate to see that thing go up in fire. I think I'd run the othe way. :duck:


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## Deathyak (Jul 18, 2009)

OK quick question...

I have a $5 smart charger that automatically chooses the voltage, and charges about a little under 200 mAh I hear... Its supposedly rated at 380, but it appears to take longer than 2 hours to charge a 14500. Furthermore, it won't charge past 4.17 volts. It'll stop, wait for the battery to drop below 4.17, then charge it back to 4.17. Left if for hours on end and it won't get any higher.

Is this a "safe" charger for unprotected 14500s?

[BTW sku.14885]


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## recDNA (Jul 18, 2009)

What scares the heck out of me after reading this thread is the potential danger of even primary lithiums let alone rechargeables.

Has anybody ever determined at what temperature primary lithiums ignite?

Have there been any recorded cases of primary lithiums exploding in flashlights?


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## Black Rose (Jul 19, 2009)

recDNA said:


> What scares the heck out of me after reading this thread is the potential danger of even primary lithiums let alone rechargeables.
> 
> Has anybody ever determined at what temperature primary lithiums ignite?
> 
> Have there been any recorded cases of primary lithiums exploding in flashlights?


Yes, there have been recorded cases of primary lithium cells exploding in flashlights. There are several threads around here about those incidents.

With brand name cells, it was caused by using mismatched cells (different voltage levels) in a multi-cell light. That results in the stronger cell reverse charging the weaker cell.

With cheap no-name Chinese cells, they were caused by QC issues. 

I've been following your posts and concerns you've raised about lithium cell safety (primary & rechargeable). 

I can relate to your concerns about rechargeables. It took me close to a year of reading various threads on here before I decided to get into Li-Ion rechargeables. 

It was only after reading and absorbing all of the information and knowing full well what I was getting myself into did I get into Li-Ion cells.
I am glad I did, as it opened up many new lighting possibilities that I otherwise would have missed out on.

Keep in mind that these issues, while they can happen, are rare.
You as the end user need to take precautions and be aware of what you are doing.

My father-in-law absolutely loves my Solarforce L2 lights and would love to have one, but there is no way in hell I would ever get him kitted out with one simply because he is so careless when it comes to batteries, especially rechargeables.


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## Black Rose (Jul 19, 2009)

4sevens said:


> JSB is busy with his other ventures.
> 
> Both were and still are respected members of this community. :twothumbs
> 
> ...


In case others reading this weren't aware, JSB has fallen on hard times lately.

You can read about his recent 700 mile walk  over at EDCF.


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## VidPro (Jul 19, 2009)

Deathyak said:


> OK quick question...
> 
> I have a $5 smart charger that automatically chooses the voltage, and charges about a little under 200 mAh I hear... Its supposedly rated at 380, but it appears to take longer than 2 hours to charge a 14500. Furthermore, it won't charge past 4.17 volts. It'll stop, wait for the battery to drop below 4.17, then charge it back to 4.17. Left if for hours on end and it won't get any higher.
> 
> ...


 
automatic is never "safe"  but then again neither is some peoples manuel  
from the specs you presented this is (about) how you would want it to work, just you should not leave it on the charger anyways, that is just asking for some high tech piece of junk to bite you.
also manually check your cells for self discharge (especially the 14500s) to insure that they are still alive, most do not last good time, although at the RATE of charge it is unlikly to cause any ignition, still a user knowing that the battery still works before jamming it into any charger is some of the safest things you can do.
AND 
NEVER use this auto junk on an SERIES set, specially with Un-protected, you always want *balancing* or singular channel charging or finishing at least. you CAN "get away with" series charging with protected cells, but not at all with unprotected. 
Protected cells will just not be all charged the same,
unprotected the charge differential has no singular cutoff, 
so although the TEAM could be within the (say) 8.4V for 2,
3.8V+4.6V still equals 8.4v and i think you can see the problem with that.


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## LOUSYGREATWALLGM (Jul 19, 2009)

Can you tell me what are the things to do to determine that the batteries are still good to recharge?


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## VidPro (Jul 19, 2009)

LOUSYGREATWALLGM said:


> Can you tell me what are the things to do to determine that the batteries are still good to recharge?


 
the voltage "holds" on li-ions when they are good, normal good cells have very very low self discharge, in fact i can have one sit charged for 6months, and not even know it wasnt fresh charged.
(some protection curcuits can have a tiny parasitic discharge of the cell, so protected is different)
they should not heat on the charger , this goes hand in hand with the rest of the stuff, a bad one will not "accept" a charge as readily, depending of course on the rate.
The capacity should be at LEAST 50% (if not 80%) of what it was when it really was new, this also goes hand in hand with higher self discharge, and charge acceptance.
if the capacity or your runtime with it compared to what your used to, drops severly, then it is suspect. 

li-ions that the voltage has dropped below 2.4v and been that way for a long while, usually are not going to be good after that, even if they seem ok at first.
(protected cells that read 0v could be cut-off and at ~2.4-2.7v depending on the curcuit)

14500s (because that was discussed previous) that are neer 2 years should be suspected, most of the 14500 i have tested over long term do not hold up :-(


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## recDNA (Jul 19, 2009)

Black Rose said:


> Yes, there have been recorded cases of primary lithium cells exploding in flashlights. There are several threads around here about those incidents.
> 
> With brand name cells, it was caused by using mismatched cells (different voltage levels) in a multi-cell light. That results in the stronger cell reverse charging the weaker cell.
> 
> ...


 
Yes, I intend to stick to SINGLE 18650 or the thinner version (17 something) flashlights to diminish the odds of an incident. I'm leaning toward Trustfire cells rather than AW because they are half the price and folks here seem to favor them over Ultrafire when it comes to safety.

I like pocket rockets so no need for a double 18650 flashlight. I have my TK40 when something bright and big is required. I haven't been able to find the Stanley HID at any local Walmarts but that's in my future as well.

I do have lots of lithium primaries in AA and CR123A size and now I'm worried about them as well. They do get hot in the flashlight and the ones in my car get very hot in the sunlight. It appears up to 140 degrees is safe from what I've read but car interiors can go to 150. 

My TK40 with ultralithiums doesn't get very hot but the MG PLI does get pretty warm with lithium primaries. It's not too hot to hold but I need to check battery temperature to make sure it stays below 140 F. I think the PLI will be a little safer with 18650's than lithium primaries when in high mode.

It would be cool to conduct a poll of all CPF members to see how many have had serious incidents with Li-ions and LiMnO cells. I don't dare do it because somebody will jump down my throat for repeating some old thread but with your credibility it could get a good response.

I don't think you will hiding it in this section though. It will have to be in the LED section to get the viewership we need for good data analysis. Of course if I post such a poll in the LED section it would be moved but if YOU did....

If I were an EE doing a graduate thesis on this subject I know I would want to tap this pool of users for a scientific survey.


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## recDNA (Jul 19, 2009)

I've seen threads about batteries venting in flashlights or exploding in chargers but have any flashlights actually been turned into shrapnel?

Oh, and is the dual pocket charger in batterystation now the same as the Yoho 122?


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## Rexlion (Jul 19, 2009)

I bought a modded 18650 light in the marketplace and it came with a battery. I tried putting it in the charger and it didn't want to fit. In the process of trying, the top button got slid over to one side. I recentered it with my finger, then got to looking at the battery... and realized it was not a 18650 but a 18700. :huh: It says SenyBor CGR18700A on it.

My main question is, may I have damaged the battery when the top button got shoved over?

The seller suggested that I could recharge it by running wires from the charger contacts to the battery ends. What is the general feeling on this?

FWIW, the battery feels like it has a protection strip running down the side.

Oh, I just remembered one more question: is it ok to touch multimeter leads to the contacts while a battery is charging? I wasn't sure if it might damage the meter or do something else. I was curious about trying to take a voltage reading a bit before the charge cycle ends, if possible.


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## Black Rose (Jul 19, 2009)

recDNA said:


> Oh, and is the dual pocket charger in batterystation now the same as the Yoho 122?


Yes it is. I bought two of those in the last few months.


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## Rexlion (Jul 21, 2009)

Rexlion said:


> I bought a modded 18650 light in the marketplace and it came with a battery. I tried putting it in the charger and it didn't want to fit. In the process of trying, the top button got slid over to one side. I recentered it with my finger, then got to looking at the battery... and realized it was not a 18650 but a 18700. :huh: It says SenyBor CGR18700A on it.
> 
> My main question is, may I have damaged the battery when the top button got shoved over?
> 
> ...


 
>> Bumping these questions, still hoping for some answers. . . . . . . . :wave:


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## flasohollic (Jul 21, 2009)

Rexlion said:


> >> Bumping these questions, still hoping for some answers. . . . . . . . :wave:



Your battery should be fine..

Yes if the battery have protected circuit it would have a metall strip on the side,, this make the circuit.

Running wires to side is noe issue,, but be carefull nor to make them contact each other (shorting)

its very clever to use a multimeter to check the voltage and current if you dont trust the charger\battery, doing so is no issue at all.


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## flasohollic (Jul 21, 2009)

Rexlion said:


> >> Bumping these questions, still hoping for some answers. . . . . . . . :wave:



There is noe issue to use a multimeter, its a must if you dont trust the charger\batterys voltage ore current.

It doesnt mather how you contact the batterys to the charger, just make sure not to make a short circuit and + and - is correct


The battery is a metall casing so i dont think you have damaged it


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## Rexlion (Jul 22, 2009)

Thanks very much, I appreciate the answers. I definitely wanted to be cautious and ask before doing something with lithium rechargeables that I hadn't done before.


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## 325addict (Jul 22, 2009)

Just because these accidents (selecting wrong number of cells in a misty menu) can and WILL happen now or in the (near?) future, I decided to design and build my own charger.
It meets ALL criteria for a safe (and by that, I mean a SAFE!) charger:

1. Charging voltage: exactly 4.200V
2. NO trickle charge
3. charging cutoff at point where current falls under 3% of rated capacity
4. charging doesn't start when cell voltage (in rest) is under 2.5V
5!! an extra protection is built-in: as soon as the voltage comes above 4.25V for ANY reason, the charger will shut down for as long as this error occurs.

Furthermore, charging current can be selected: 250mA, 500mA or 1A. This is the ONLY user-selectable setting and won't cause fires as long as you don't try to charge a 10180 cell at 1A.
LED's will tell you:
1. CC charging at the moment (red)
2. CV charging at the moment (yellow)
3. ready (green)
4. < 2.5V (no charging possible then!) RED LED
5. error (charging voltage is above 4.200V maybe due to an internal defect)
RED LED too.

This one I will leave unattended at night if it has to be. Of course, I'd rather keep an eye on it, but WHEN it sometimes just has to do without that eye, I know it's protected with that extra safety-circuit.

By the way, I got a batch of DSD chargers that charge up to 4.26 Volts!
So.... SAFE??? Not really :mecry:

Timmo.


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## recDNA (Jul 23, 2009)

What would be the best thread for me to read about the df between Li-Ion and Li-Poly batteries? I've read a few that weren't very good.


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## cy (Jul 24, 2009)

ah... my old thread... back from the dead


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## Kestrel (Jul 24, 2009)

cy said:


> ah... my old thread... back from the dead


Well, quality never goes out of style... :thumbsup:


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