# General Li-ion safety



## SilverFox (Feb 16, 2009)

Here is a thread that has a lot of good general safety concerning Li-Ion cells in it.

Greatest danger using Li-Ion cells occurs during charging

There are a lot of things in this thread that can help people avoid problems with Li-Ion cells.

Tom


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## Hawkeye5 (Mar 6, 2009)

Thanks. As a new user of Li-ion cells I might say that scared me straight. I didn't know what I didn't know.


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## Trailbasher (Mar 7, 2009)

Yes, thanks....plenty of good info and links to answer some of my questions (fears)


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## llmercll (Apr 9, 2011)

*Beyond the basics for Li-ion safety?*

I've been doing a lot of reading on lithium rechargeables and must admit, I'm terrified. I ordered some cheap batteries (trustfire protected) and charger (WF-139) and would like to ask a couple questions that have been on my mind. I really would like to get more expensive chargers and batteries, but I'm not "that" into lights yet that I'd like to take that 4x 5x price increase, and even then theres no guarantees.

To make sure I understand this, the main threat is the battery releasing poison gas, the gas building up in the tube, and one end of the light blowing off with extreme force, like a roman candle and likely catching fire. Are there any additional safety measures you could take to protect from this (aside from treating your batteries well), like making a hole in the flashlight body/clicky, or not screwing on your tailcap too tight?

The stories I've read that resulted in an explosion usually have a "non tragic" ending. No one got seriously hurt, at most suffered some light wounds but no fingers lost, no blindness, no house burning down, no death. That leads me to believe that even in a worse case scenario you are given adequate warning either from hissing or heat, to chuck that flashlight and yell grenade. Has anyone heard any tragic stories caused by lithiums in flashlight? What are some more warning signs?

I'm looking for some "above and beyond" safety tips. I'm a stickler for safety and would never forgive myself if something like a flashlight blew off my hand or burned down my home.

thanks!


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## tolkaze (Apr 11, 2011)

*Re: Beyond the basics for Li-ion safety?*

afaik, the released gasses when venting are not poisonous as such (at least in the low concentrations in this circumstance)

You could try drilling a hole in your light to vent, however this would eliminate any water-proofness, and wouldn't make a huge difference anyway... it might only blow up a little bit, or just shoot a 6 inch flame out the side if it went critical. 


There are a few horror stories around, but seriously, there are hundreds of thousands of users of these type of cells, and millions, if not billions of people using lithium-ion worldwide. If it were that common, there would be far more stories to tell.

Check list:


1.) Good quality cells - Doesn't have to be AW, but it also wouldn't hurt. 

2.) Good quality charger - Can be a cheapy if you want, but you should be aware of how it works, and how it charges. If it trickle charges, or if it will feed too much current etc. Again, better known brands might be better for a reason.

3.) Get a multi-meter - This is pretty much a "must have" item. Doesn't have to be super expensive, or super accurate, but has to be consistant. Get a baseline of your cells when they have charged (around 4.2V or below) and make sure they aren't going over that level on subsequent charges. If they do, consider step 4.)

4.) Chuck cells when they need to be - If a cell is over charged, or discharged, then get rid of it. If you have charged a cell to over 4.25V then its getting a bit dangerous, and if you over discharge a cell, then it is equally dangerous. Chuck it out, and get a new cell. They are cheaper than a new house. 

5.) Use protected cells when possible - If you are new to the game, protected cells can be your best friend. Not only do they have safety features built in for when you are using them, but also when charging your cells. Can include overtemp protection, over charge/discharge, and usually include a vent for gasses.

6.) set up a charging area - a lot of us charge our cells in a metal flame proof box on a cement floor for a reason... if you are charging lots of high capacity cells, then you have higher potential for BOOM. Again, not a mandatory thing, but reccomended you at least get an area that you would consider safe to use

7.) Don't leave your cells unattended while charging. I know its a pain in the *** to charge a pair of 18650's for 5 hours, but if you leave them on overnight, you won't know how they are behaving. You should check for the temperature of the cell itself when charging, and check the charger itself. Expect a bit of warmth (10-20 degrees above body temp) but if it is too hot to touch, you got some trouble!

8.) Use the right cell for the job - if you have a high drain device, consider reading up on, and buying some quality IMR cells, if you need a cell that puts out a lower voltage, consider some LiFePO4 cells. Knowing the chemistry of the cells, and their limitations will make using and caring for your cells easier. 

Lithium Ion cells have come a long way in safety, but generally the cheapest cells on the market, can also be the most volatile. 

Anything I need to add?


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## tolkaze (Apr 11, 2011)

*Re: Beyond the basics for Li-ion safety?*

Oh, and having said all this, my first 2 chargers were WF-139's and my first cells were all ultrafires. I now have a lot of different brands, and still call on the ultrafires more often than the AW's


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## llmercll (Apr 11, 2011)

*Re: Beyond the basics for Li-ion safety?*

thanks a lot for the detailed reply!

I plan on going everything on your checklist but had a few questions =)

1. with the multimeter, max charge should be 4.2, and min discharge should be 3.7? Can I use the multimeter to test the battery while it's in the charger or will it give inaccurate result/blow up?

2. I have a little metal box I was considering using to charge in. However, how to people get the cord in there? do they just leave it cracked?

thanks!


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## pobox1475 (Apr 11, 2011)

*Re: Beyond the basics for Li-ion safety?*

I use AW protected cells, charge in Pila IBC on nonflammable surface, and use a multi meter. Don't give much thought to safety beyond that.

1) If max charge is slightly lower you will get longer life spans from cells. 4.2v is termination a lot of users go with. Charge often as letting voltage dip excessively is bad for service life too. Li-Ions are fine with simple top-offs.

2) Test cells when off charger.

3) You could use a box. Heat is enemy of all charging cells, keep this in mind. IMO a solid surface that will not burn and away from other stuff that could catch is ample.


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## VidPro (Apr 13, 2011)

*Re: Beyond the basics for Li-ion safety?*

off topic, i could have "burned my house down", and "crashed my car" by making stupid misteaks with ni-cd and ni-mh too.
some of it is just the Power, respect the power. 
Because of the ability to have high current flows enough to short a wire out and start stuff on fire, and due to cheap batteries that had no physical protection, or vents or safety of any kind, i had a ni-cd explosion, and nice fire burning in the middle of the room  and one time due to a short , a battery pack started a nice little smoldering pile in the truck while driving down the road.

it doesnt have to be lithium, to have a lot of power in it, or to be a cheap piece of junk with minimal safety features.
kids have a lot of power too, just like batteries you dont leave them alone when there Playing 

know the specs, that is one thing, a person might read the "manuel" for something they want to operate correctally, but reading a spec sheet to see how to use the battery correct is not important? if there isnt a spec sheet  then . . . that is just like getting anything else without a manuel, you use the "Try And Fail" methods till you get it right. the fail part being the problem.


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## llmercll (Apr 13, 2011)

*Re: Beyond the basics for Li-ion safety?*

Thanks for the replies =)

I have a Dilemma now. I can charge them in my room where I spend most my time, OR in my garage on the concrete floor, but I'm not going to be standing in my garage for 5 hours and don't spend much time in there.

I guess you could say what's more important, location or supervision?


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## llmercll (Apr 15, 2011)

*Re: Beyond the basics for Li-ion safety?*

bump bump!


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## VidPro (Apr 15, 2011)

*Re: Beyond the basics for Li-ion safety?*

i had to quit putting them in the garage, when the quantity of solvent, gas, paint, oil, cardboard, wood, and other stuff that would "contribute" if ever an ignition occured, there was some point where the garage was no longer "safer" .
if you have it in a tall open container where it can not "fly out", and a small fire could occur in the container and it would not cause a problem, then it is likly to be very safe.
I guess i would rather see a fire start, then to have it build up before i saw it. but if the fire will be contained, then i dont need to see anything.

odd things to add , often homes do not have smoke alarms in garages, because it can be set off by the car exhaust , here they did not put the smoke alarm in the garage, only the fire sprinklers, and the sprinklers use a different valve releace too, i did not understand. I still have not put a smoke alarm in there, but i got electric doors  where are my priorities :thinking:

Li-ion does not like to be charged in extreeme cold, but i dont know what temp that is , if it is going to be extreemly cold, then you would want to know that spec item.

i have no intention on making that descision for you, you already know enough to be aware. and it doesnt do any good to be terrified, aware and proactive, beats making error out of fear.
Had one battery in pieces in the garage, using gloves and a face mask and doing all the "right things", while i was testing something else, the garage door opened and the other person drive right over the top of my battery. :wave: sooo, you have to decide. to many factors.


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## llmercll (Apr 16, 2011)

*Re: Beyond the basics for Li-ion safety?*

I will probably do it my room then, and just have an emergency plan =)

I have a little box that would be perfect...I just don't know how i will run the wire in there. how do you guys that use fireproof boxes do it?

thanks!


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## VidPro (Apr 16, 2011)

*Re: Beyond the basics for Li-ion safety?*

you know that one of the possible RARE problems, is when the solvent gas build up in containment .
or for other batts, hydrogen and oxygen gasses, which just love to recombine quick.
like there is a YouTube with an ammobox, this ammobox had a 3-4inch gaping hole in it, running a dryer hose out, and it still freaking "blew up" harshly because the device "contained" the gasses, and was capable of "increaing the compression" on ignition of the gasses.
that is why tall and open IMO is better than this idea of trying to shut it up in safes and all.

ya got the lithium ok, but you also have a solvent , and oxigination , and its like vaporised gasses kinda thing.
now it is unlikely that you can get the kind of activity that they do when doing it on purpose, but the gasses are still a concideration.
Whoosh is better than Boom, as long as woosh doesnt lead to ketching all the other stuff you left around on fire too.


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## TyJo (Apr 16, 2011)

*Re: Beyond the basics for Li-ion safety?*

I don't think the cell is ruined if it gets discharged below 3.7 volts, as long as it doesn't stay there long. If you have good cells, good charger, and a volt meter I think its fine to charge li-ion in the house, if you are in the same room. Li-ion are used in laptop battery packs, they aren't terribly dangerous, its just most flashlights don't have the electronics in them to prevent over discharging/charging. Li-ions in a flashlight are also safe if they are single cells, or multi-cells that are matched properly (voltage, manufacturer, purchase date, etc.). From my understanding they "vent-flame" most often while they are charging after being over discharged/over charged.


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## VidPro (Apr 16, 2011)

*Re: Beyond the basics for Li-ion safety?*

Plus
shorts or reverse charge, all good reasons for effective non-shorting Added curcuit protection.
and The internal to the cell itself "mechanical protection" the anode disconnect and PTC device, and for the gassing disconnect to work a good proper seal between the anode dis-connect device and the fixings in the cell.
and internal breakdowns and shorting internally, plating of lithium , which can be via bad cell, or improperly treated, or improperly made cell.


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## llmercll (Apr 20, 2011)

*Re: Beyond the basics for Li-ion safety?*

http://www.toyrc.com/li-polymer-battery-safe-charging-bag-white-1880.html

what do you guys think about this? It says lipo so idk

thanks!


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## HKJ (Apr 20, 2011)

*Re: Beyond the basics for Li-ion safety?*



llmercll said:


> http://www.toyrc.com/li-polymer-battery-safe-charging-bag-white-1880.html
> 
> what do you guys think about this? It says lipo so idk



I have been using LiIon for a a few years and have never had a fire or explosion or even a hot cell, even when doing many charges and discharges.

With that said, I like them and has a couple of them. If an accident happens they will prevent a LiIon "explosion" to throw hot (burning) stuff around. But you might still get a local fire at the sack.

Also note that LiPo for RC use are more likely to explode than normal LiIon cells.


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## WillyB (Apr 20, 2011)

*Re: Beyond the basics for Li-ion safety?*

A lot of useful info for a new guy.

Thanks


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## llmercll (Apr 23, 2011)

*Re: Beyond the basics for Li-ion safety?*

thanks for the infos!!

I got my cells today. I measured their initial voltage and most were between 3.6-3.8. good right? After charging though, it seems my charger brings them up to about 4.21. Is that ok?

thanks!


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## jasonck08 (Apr 23, 2011)

*Re: Beyond the basics for Li-ion safety?*



llmercll said:


> thanks for the infos!!
> 
> I got my cells today. I measured their initial voltage and most were between 3.6-3.8. good right? After charging though, it seems my charger brings them up to about 4.21. Is that ok?
> 
> thanks!



Yes 3.6 to 3.8v is fine for long term storage, with 3.6v being a little on the low side for most li-ion cells. 4.21v is fine, as regular Li-ion cells should be charged at 4.20v +/- 0.5v.


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## shao.fu.tzer (Apr 23, 2011)

*Re: Beyond the basics for Li-ion safety?*

I still think all multi-cell Li-Ion lights should have a forward (bezel end) venting, one-time use safety feature, kinda like an airbag. You would lose your water proofness once it blows, but at least no one would be hurt and your light would still be intact. Then you could just buy a new "venting collar" that would slip in place of your old destroyed one... Why not? Hey... If anyone uses this idea, please cut me a little something.. like a free light and some inventing credits, hell, a small portion of your proceeds in sales... You listening Surefire?????? 

Shao


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## llmercll (Apr 23, 2011)

*Re: Beyond the basics for Li-ion safety?*

Lol I totally agree. I read a few articles about battery accidents and the lights involved almost always consisted of multiple cells =p


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## shao.fu.tzer (Apr 23, 2011)

*Re: Beyond the basics for Li-ion safety?*

Maybe a latex condom kinda membrane that would swell so you would know when your're lights about to go - then the pressure would be released through the weakest point - the membrane, instead of blowing your tailcap out or blasting your 16340 cells out the bezel into your eight year old nephew's forehead. That way you could retain water proofness. The membrane would be cheap and easily replaceable. Flashlight companies.. if you want to hire me, I am currently looking for steady work. ;D

Lol,
Shao


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## shao.fu.tzer (Apr 23, 2011)

*Re: Beyond the basics for Li-ion safety?*

DOUBLE POST


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## bestsystem (Oct 28, 2011)

*Re: Beyond the basics for Li-ion safety?*



tolkaze said:


> afaik, the released gasses when venting are not poisonous as such (at least in the low concentrations in this circumstance)
> 
> You could try drilling a hole in your light to vent, however this would eliminate any water-proofness, and wouldn't make a huge difference anyway... it might only blow up a little bit, or just shoot a 6 inch flame out the side if it went critical.
> 
> ...



good job !


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## GrimCreaper (Nov 1, 2011)

*Re: Beyond the basics for Li-ion safety?*

What kind of container would be good, and where can i get one? I have failed rather miserably on this


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## snakyjake (Nov 2, 2011)

*Re: Beyond the basics for Li-ion safety?*

If you could add:
Minimum voltage before cell damage?
Don't use multiple cells (e.g. 2xRCR123, try to use 18650 instead).






tolkaze said:


> afaik, the released gasses when venting are not poisonous as such (at least in the low concentrations in this circumstance)
> 
> You could try drilling a hole in your light to vent, however this would eliminate any water-proofness, and wouldn't make a huge difference anyway... it might only blow up a little bit, or just shoot a 6 inch flame out the side if it went critical.
> 
> ...


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## Joe Talmadge (Dec 23, 2011)

*Li-ion beginner primer*

12/27/11: I have explained the abbreviations and battery chemistries a bit at the end of the LI ION BATTERY CHEMISTRY AND SAFETY section. I added some words about using a DMM at the end of the recommendations section.
12/26/11: Added A BIT MORE DETAIL ON CHARGING, after the charging section

Hi folks, on other forums I read, I often notice a lack of info on Li Ion batteries. Most disconcerting, people have experience with alkaline and Nimh batteries, and assume Li Ion care and feeding is as simple, and the consequences of a mistake similarly (usually) small. I wrote a quick beginner primer, that may actually be useful here too, though folks here tend to be a lot more knowledgeable. In the meantime, I'm asking for feedback on this: is it factually correct? Are there important details I left out? Is it useful? Some of the emphasis in the article has been lost -- I was able to underline important points, but that underlining has disappeared in this forum (I'll change to bolding later today).

I'm going to try to make this really short, which means I'll drastically simplify and generalize. If anyone things I've oversimplified to point that the information looks incorrect, let me know and we'll discuss changing it right here in the primer. If you just want to add detail, we should let those stay as follow-ups. The reader should know that I've simplified a lot, you should be checking places like battery university and candlepowerforums for more detail; I mostly want to jumpstart you into a place where you're vaguely safe.

WHY WRITE A PRIMER?
I'll tell you first, I'm a bit conservative when it comes to things like safety. For all the positives of Li Ion batteries, the downside is that the consequences of making a mistake can be serious -- explode in your light or burn down your house serious. On the other hand, let's keep some perspective: many people use these batteries in hobbies like RC, and homes aren't burning down left and right. That said, I don't want *you* to be the statistic. I look at Li Ion batteries like a firearm: understand and follow a few simple rules, and there's no reason to fear them. But these are not the no-brainer technology that alkalines are.

I'm going to discuss the very basics of batteries and chargers. I'm going to use some examples of specific products that I feel violate the rules. And I'm going to try to give you enough info to evaluate that claim on your own. I will make specific recommendations for beginners at the end.

WHY GO WITH LI ION?
•	If you use your light a lot, rechargeables will be much cheaper to run in the long run, and easier on the environment
•	Modern lights are increasingly running at higher performance with Li Ion rechargeables. For example, the current XML based V10R is running 150 lumens on a CR123 primary, but over 400 lumens on a RCR123 or 16340 (both terms for a li ion rechargeable).
•	Even though lithium primaries have higher capacity than lithium ion rechargeables, when I walk out the door with my rechargeable, I know my light is at full charge. With primaries, I'm never sure, since I'm not going to replace a primary that seems to be running well just because I've used it for the past week, and I can't just top it up.

LI ION BATTERY CHEMISTRY AND SAFETY
There are multiple battery chemistries for Li Ion batteries. I am going to almost solely discuss LiCo, but there are other chemistries popular in lights such as IMR and Lifepo4. I will contrast with IMR occasionally.

The thing about LiCo batteries is that the chemistry is not safe. By not safe, I mean, conditions can occur where the battery goes into thermal runaway, at which point it can vent violently or explode. A safer battery chemistry might cause the battery to shut down under these conditions, but because LiCo batteries go into runaway, I am only going to be discussing *protected* batteries from here on out: those batteries with built-in protection including a protection circuit and other safeguards that shut the battery down and prevent other conditions that can cause problems. However, I'll note that I never rely 100% of mechanical protection, these are inexpensive parts that sometimes aren't perfect. Having a safety doesn't mean you can point a loaded gun at someone 

IMRs, by contrast, use a safer battery chemistry, and so don't have protection circuits. But IMRs have lower overall capacity than protected LiCos. Still, as we'll see, IMRs have characteristics that can let them outperform LiCos under some circumstances.

A quick summary of the most popular chemistries:

LiCo (LiCoO2) aka ICR batteries:
•	Are the batteries usually being discussed when someone mentions something like “protected AW 14500” without any other qualifiers
•	4.2V max charge, 3.7V nominal voltage
•	Not a safe chemistry, so can be purchased with a protection circuit that guards against overcharging and over-discharging
•	Higher energy density, but lower charge and discharge rates, than the other batteries in this list
•	Are the batteries I use in lights that can handle 4.2V and do not demand a higher current than what LiCo can deliver
•	Chemical composition is lithium cobalt oxide

IMR (LiMn204) batteries:
•	4.2V max charge, 3.7V nominal charge
•	Safe chemistry, so is not available with a protection circuit. But that means the consumer must guard against overcharge and overdischarge themselves. 
•	Slightly lower energy density than LiCo, but can sustain much higher discharge and charge rates. I use these in lights that can handle 4.2V batteries but require a higher discharge rate than LiCo can handle, like some of the newer demanding XM-L lights
•	Chemical composition is lithium manganese oxide

LiFePO4 aka IFR batteries:
•	3.6V max charge, 3.2V nominal voltage
•	Safe chemistry, so is not available with a protection circuit. But that means the consumer must guard against overcharge and overdischarge themselves. 
•	Lower energy density than LiCo, but can sustain higher discharge and charge rates. 
•	Chemical composition is lithium iron phosphate 


CHARGING 
These batteries use a CC/CV charging algorithm, where in the first phase of charging, an initial constant current is used. When the battery reaches 4.2V, that voltage is kept constant, until the current dwindles to a percentage of the initial current ... and when that happens, the charge terminates. You may be as shocked as I was to learn that the vast majority of production chargers do NOT conform to the above well-known and manufacturer-approved specs. We'll talk about a few chargers that do, later. One thing we do want to do: *make sure we use a charger that's been shown to use the correct algorithm. But we don't want to completely depend on correct operation: as a rule, put your charger on a relatively fire resistant surface, stay with it while it's charging, and take your batteries off the charger when the light turns green.* Technically, we've improved our safety by using a battery with overcharge protection and a charger that uses the proper algorithm; but if those two things go bad (and let's face it, with your luck, they might  ), bad things can happen. 

The other thing to watch out for is that a li ion that's been discharged too low is *not safe to recharge or use, in the light-your-house-on-fire sense.* Again, we're talking about batteries with protection circuits that should protect against that, but those protection circuits cost a few cents and can go bad. Do not make it a habit of letting the protection circuit trip to tell you when to recharge. There's very little penalty for topping off Li Ion rechargeables, which is a nice feature of the technology, it means you can top off often. I suggest you do so. If the protection circuit fails to trip, you may be recharging from an unsafe voltage.

The other feature of recharging: you really don't want to recharge at over 1C for smaller LiCo batteries and .7C for larger ones – *check your battery’s specs to see the safe charging rate for your battery.* C stands for the capacity of the battery. For example, a protected RCR123 currently is usually rated at 750 mAh. That means you don't want to use a charger that uses a current of greater than 750 mA, and really, you should stick with .8*750mA=600mA. Note that IMR batteries have different charging specs, with rates nearly reaching 3C.

A few examples now: the highly rated Pila IBC charger has a charging current of 600mA. That means you're good with batteries as small as a protected RCR123. But you certainly should not charge a 10440 (350 mAh) or smaller on this charger. For those of you who followed the now-recalled Jetbeam charger, you may remember me being critical in those threads. That's because Jetbeam claimed 10440 support for this charger, even though the charging current for a single battery could be as high as 1000 mAh. That's nearly 3C, and way outside manufacturer safety recommendations!!! So, I hope you now know how to tell if a charger's charging current is safe for a particular Li Ion battery: look at the capacity written on the battery, and stick to the battery manufacturer’s recommendation; .7C will usually be safe, when in doubt.

For reference, below is a chart of a CC/CV charge. The interesting points:
•	Current starts out constant, with voltage rising
•	When voltage hits 4.2V, it gets held constant, while current diminishes
•	Current reduces until it hits a cut-off threshold (50mA, in this case), at which point the charge terminates (current should be zero or close to it, at the cutoff).

Many production chargers miss the mark on a number of points, in particular, the final termination. This could lead to dangerous conditions, 

A BIT MORE DETAIL ON CHARGING
Below is a graph of a charger that correctly follows a CC/CV algorithm, courtesy of HKJ of CPF. I include it so you can see what a charging cycle should look like. Again, many chargers do not follow the algorithm properly. Among the common problems: at the end of the cycle, the charger must terminate, but many chargers keep applying what is essentially a trickle charge, which is arguably a dangerous mistake, and a good reason to choose a charger which has been reviewed and proven to follow a reasonable approximation of CC/CV, and to follow good charging practices.

Below, what you see in the first portion of the graph is the CC (constant current) stage. In this case, the current is kept constant at 1.0A while the voltage rises. When the voltage hits 4.2V, the CV (constant voltage) stage starts, where 4.2V is applied and the current naturally falls. When the current matches the termination current, you see the charger terminate at the vertical yellow line – we know proper termination has been achieved because current drops to 0 abruptly at that spot.







Another good practice is to have some way to measure the voltage of your Li Ion batteries, to make sure they’re coming off the charger with safe voltages, that you haven’t discharged to an unsafe voltage, etc. The LiCo batteries we’ve been discussing have been spec’ed to charge to 4.2V when fully charged, plus or minus .05V. Note that battery voltage will settle down a few hundredths of a volt, in the couple of hours after it comes of the charger; you can see that happening in the graph above, when the voltage represented by the red line starts sagging a bit after the yellow line indicating charge termination. If your battery is older, or you’re using a spacer, you might see lower voltages, even below 4.15V. Using an inexpensive digital multimeter (DMM), or the voltmeter that’s integrated into your Cottonpickers charger, you can check these voltages. I particularly do not want to see batteries coming off the charger higher than spec; if that happens, it’s important to figure out why, and resolve the issue immediately. Below 1.5V, these batteries start forming shunts that can internally short the battery, leading to fire or explosion; if a battery gets down that low, I retire it.



USING (DISCHARGING) LI ION BATTERIES
LiCo batteries want to be discharged at no more than 2C (read the above section if you don't remember what "2C" means). For a 750 mAh protected RCR123, that means no more discharge than 1500 mA. IMR batteries can handle up to 8C. That means for a 16340 IMR at 550 mAh, no more than 4400 mA (4.4A). By knowing the current demand of a flashlight, you can tell how a battery will run. 

More real-life examples. There are a couple of XML powered lights that run on a single CR123A or RCR123A/16340 to put out 400+ lumens. For example, Jetbeam and the Sunwayman V10R XML put out well over 400 lumens, and to reach that output, they are pulling well over 2A (2000 mA) from the battery. We know from experimenting, IMR batteries can outperform LiCo batteries in these lights, even though IMRs have lower capacity. Can you tell why, based on the discussion above? These lights are pulling way more than the manufacturer-recommended 2C for LiCo batteries, and those batteries sag quickly under the load. IMRs, which can handle the load, provide higher output for longer -- and the current requirements can be safely met by IMRs. I run an IMR in my v10r, and since IMRs do not have an overdischarge protection, I just take care to charge it often. 

HOW DO I KNOW THE SPECS ABOVE?
You'll need to research some of the specs above yourself. I get the battery's manufacturer recommendations right from them. For example, AW posts the charge and discharge ratings on his batteries right on his forsale page on cpfmarketplace. I read reviews of chargers and lights to determine things like whether a charger is following the correct algorithm, what its initial charging current is, what a particular light's current draw on high is, etc. I learned most of what I know from the battery section on CPF, a good place for more advanced topics. I strongly suggest you be self-sufficient in determing safe ranges for your batteries and chargers – as I outlined above, there are flashlight and charger manufacturers making recommendations that are contrary to the recommendations from the battery manufacturers. I typically take the battery manufacturer’s recommendations as primary, and will not use a battery in a light or charger whose specs are in contrast with the battery manufacturer’s safe ranges.

RECOMMENDATIONS FOR BEGINNER SETUPS
*Li Ion technology is not the place to cheap out. Buy quality from the beginning for both safety and top performance.* Here are the recommendations I make to my friends who are just starting:

Buy your protected LiCo or IMR batteries from these manufacturers, who have proven to have very high quality high-performing batteries: 
•	AW
•	Redilast
•	Callie's Kustoms

Buy your charger from these manufacturers, who have been shown in reviews to use proper CC/CV algorithm with proper termination:
•	Pila IBC: use this to charge 1 or 2 batteries at 600mA
•	4sevens: single-bay charger, switchable between 500mA and 1000mA charging rates
•	Cottonpickers: uses clips and magnets instead of a bay, and works off a USB port. You can order multiple configurations which have different charge rates. For example, I have a charger that I can set to 200mA or 500mA charge rates, to handle relatively bigger or smaller batteries (this is the only charger I'd use to charge a 10440, since I can charge that at a safe 200mA rate). This charger can also be bought with a built-in voltmeter so you can see the voltage on your batteries.

I specifically avoid and do not recommend any of the products from the *fire companies, etc., in my opinion they've been shown to have inconsistent quality. I'm not claiming the ones above are the only safe choices, but just ones I personally feel good about.

You also want to have a way to check the voltage on your batteries. An inexpensive Digital Multimeter (DMM) is generally good enough. The built-in voltmeter on a Cottonpickers charger is good as well. Thus armed, you can:
•	Check the voltage of your batteries off the charger, to make sure they’re not being dangerously overcharged
•	Check the voltage of your batteries after use or long-term storage, to see if the voltage has dropped dangerously low (<1.5V), or if the protection circuit has tripped (0V).
•	In multi-battery lights in which the batteries are in series, you can try to ensure you are using two batteries with about the same capacity, which will help avoid dangerous conditions that can occur when batteries are not balanced.


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## HKJ (Dec 23, 2011)

*Re: Feedback requested: Li Ion beginner primer*



Joe Talmadge said:


> But you might think twice about charging an IMR 16340 (550 mAh) on this charger



Why that, I would have no problems charging a IMR 16340 on a 1A 18650 charger?

Also note that a good 18650 cell has higher capacity than 2xCR123 cells.

One of the advantages of LiIon is the charging, they can always be charged to full capacity, without loosing any lifetime on the cell.


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## Joe Talmadge (Dec 23, 2011)

*Re: Feedback requested: Li Ion beginner primer*



HKJ said:


> Why that, I would have no problems charging a IMR 16340 on a 1A 18650 charger?



HKJ, I appreciate your response... IMRs do have a 1C charge recommendation (right?), and you're charging at nearly 2C at 1A. Isn't it very likely you're hurting battery life by nearly doubling the recommended charging rate?



> Also note that a good 18650 cell has higher capacity than 2xCR123 cells.
> 
> One of the advantages of LiIon is the charging, they can always be charged to full capacity, without loosing any lifetime on the cell.



Good points, I thought I reflected the 2nd point, I'll see if I can make that clearer. The point about LiCos potentially having more capacity than a different primary setup is a good one too


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## HKJ (Dec 23, 2011)

*Re: Feedback requested: Li Ion beginner primer*



Joe Talmadge said:


> HKJ, I appreciate your response... IMRs do have a 1C charge recommendation (right?), and you're charging at nearly 2C at 1A. Isn't it very likely you're hurting battery life by nearly doubling the recommended charging rate?



Only regular LiIon, IMR can take much more. The IMR 16340 has a maximum charge rate of 1.5 ampere.


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## Joe Talmadge (Dec 23, 2011)

*Re: Feedback requested: Li Ion beginner primer*

Thanks, I'm going to correct that in the initial post, but your response will serve to document who corrected it... I just looked up IMR specs and that confirmed your statement


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## samgab (Dec 23, 2011)

*Re: Feedback requested: Li Ion beginner primer*

Looks like good info, that should probably be stickied. 
It answers a lot of the same questions that get asked again and again and again... We could just direct people to a thread like this.
I think a lot of people go a wee bit overboard on the safety concerns and dangers of modern li-ions; but I guess it's much better to err in that direction than to be overly complacent, and have something go wrong, so I suppose that's okay. At least to make all the relevant warnings, and the user can decide for themselves.
Maybe a chart demonstrating what CC/CV looks like could be useful.
Something like this perhaps:


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## Bigmac_79 (Dec 23, 2011)

*Re: Feedback requested: Li Ion beginner primer*

I don't have enough knowledge to add a lot here, but I'll pose a question that you could answer. It would be useful to add info on how low it is safe to discharge a lion to (ICR chemistry or IMR chemistry), and how protection circuits fit in with that. Also, I know some cell manufacturers note that cells should not be stored long term below a certain voltage.

Thanks for getting this together! I was actually just thinking today how useful this would be to have available, as most people asking lion questions just get told "use the search function" and "go to batteryuniversity.com". This will be a really handy resource for the CPF community once it is completed.

:twothumbs:


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## HKJ (Dec 24, 2011)

*Li Ion beginner primer*



samgab said:


> Maybe a chart demonstrating what CC/CV looks like could be useful.



I believe that it is better with some markings on and also showing what happens after the charge current is turned off:




This battery drops to 4.18 volt when charge current is turned of and is down to 4.16 volt after an hour.


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## Cavi Mike (Dec 24, 2011)

*Re: Feedback requested: Li Ion beginner primer*

What exactly is supposed to happen when you try to charge a Li-Ion battery that has been over-drained? I've had a few Li-Ion cel-phone type batteries go under-voltage and refuse to charge but I used a pretty shade-tree method to get them back to life and I know of 3 that are still in use and function normally.


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## Joe Talmadge (Dec 24, 2011)

*Re: Feedback requested: Li Ion beginner primer*

Thanks guys, lots of good comments, I'll start reflecting some of them. I like the idea of a graph in the charging section. HJK, do you own that graphic you just posted, and if so, do I have permission to include it in the guide with an attribution to you?


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## Joe Talmadge (Dec 24, 2011)

*Re: Feedback requested: Li Ion beginner primer*

CaviMike: if you are playing some kind of trick to recharge a battery which has been shut down by the protection circuit to prevent overdischarge, and it's still sitting around 2.7-3V, I'm not exactly sure what the dangers are, I don't understand the corner cases ... but if it's too much lower than that, for too long (<1.5V for a week?), the battery can form deposits that cause shorts, and become more fragile internal and susceptible to impact etc.


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## hank (Dec 24, 2011)

*Re: Feedback requested: Li Ion beginner primer*

Something like this is worth having
https://www.google.com/search?q=battery+charging+fireproof+bag

Easier (though less protection) than using a fireproof metal box, or a big concrete patio on which to do your recharging.
A photoelectric smoke alarm over the charging location is also a good idea.

Along with a clear awareness how _not_ to try to deal with a fire when a li-ion battery starts to go up in smoke.


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## Joe Talmadge (Dec 24, 2011)

*Re: Feedback requested: Li Ion beginner primer*

Those bags look like a nice insurance policy for the super cautious among us, if they really work. If you're using something like a Pila IBC, would you just shove the entire charger into the bag? Or are they made for chargers with leads instead of bays?


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## samgab (Dec 24, 2011)

*Re: Feedback requested: Li Ion beginner primer*



Joe Talmadge said:


> Those bags look like a nice insurance policy for the super cautious among us, if they really work. If you're using something like a Pila IBC, would you just shove the entire charger into the bag? Or are they made for chargers with leads instead of bays?



They are really for RC guys, using hobby chargers, and who are charging at high rates, like 5A-10A. If you put a Pila charger or similar in the bag, you'd probably do more harm than good, because of heat. You'd be putting all the electronics in the bag, whereas they are designed to take RC battery packs where the electronics of the hobby charger remain out of the bag.


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## 45/70 (Dec 24, 2011)

*Re: Feedback requested: Li Ion beginner primer*

Hi Joe. Your looking pretty good, I'd say. One thing that may be OK as it is, but most LiCo cells of 18650 size and larger have a maximum recommended charge rate of 0.7-0.8 C, or some even considerably less. You can probably get away with charging most of these cells at a 1C rate, but it's not good for them. You may want to work this point in somehow.



Cavi Mike said:


> What exactly is supposed to happen when you try to charge a Li-Ion battery that has been over-drained?



Just to add something here. The biggest danger in over discharging cells is that at a voltage of around 1.5 Volts/cell, copper shunts can form within the cell, which as Joe mentioned, can cause the cell to short internally. These shunts may, or may not form, but the longer the cell is in a low voltage state, the more likely this may happen.

The scariest thing about these shunts is, while a short is probably more likely to occur when attempting to charge the cell, it could also happen at any time, while the device is in use, or even when not in use, such as in your pocket, or stored in a drawer. The other thing about these shunts is once they start to form, they continue to grow and the condition is irreversible. This results in a cell or battery that may seem fine one day, but may develop internal shorts the next day, after a week, or even months later. Of course, it's also possible that shunts never started to form, in which case, nothing will happen. The only way to tell for sure, is to disassemble the cell and look at it with an electron microscope.

With something like a cellphone, usually the built in protection circuitry will prevent the cell, or cells from being discharged to a low enough voltage to cause problems. If on the other hand, a battery is drained to the point where the protection circuitry has activated, and then the battery is not used for sometime, the voltage may drop lower. Then, there may be a problem.

It is important to remember, that the discharge graph of most any cell drops like a rock at a certain point. In the case of Li-Ion cells, this point is very close to the cutoff voltage of most protection circuits. So, while self discharge of Li-Ion chemistry cells is very low, it doesn't take much for the voltage to drop significantly, once you're headed over the cliff.

Dave


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## Joe Talmadge (Dec 24, 2011)

*Re: Feedback requested: Li Ion beginner primer*

gotcha on the correction about 18650s, I'll update that


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## Jackasper (Dec 26, 2011)

*Re: Feedback requested: Li Ion beginner primer*

Very good info. Thanks for taking the time to write this up. It never hurts to have a DMM to keep tabs on voltages both before and after charging. It's so difficult to know exactly where your voltages are with most cradle/bay style chargers. Relying on the protection circuit, like you mentioned, is never a good idea. By having a meter handy, it saves alot of guesswork.


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## HKJ (Dec 26, 2011)

*Re: Feedback requested: Li Ion beginner primer*



Joe Talmadge said:


> Thanks guys, lots of good comments, I'll start reflecting some of them. I like the idea of a graph in the charging section. HJK, do you own that graphic you just posted, and if so, do I have permission to include it in the guide with an attribution to you?



Yes, it is my own and you can use it. The graph is from charging a CalliesKustom 3100 mAh cell.


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## Joe Talmadge (Dec 26, 2011)

*Re: Feedback requested: Li Ion beginner primer*



Jackasper said:


> Very good info. Thanks for taking the time to write this up. It never hurts to have a DMM to keep tabs on voltages both before and after charging. It's so difficult to know exactly where your voltages are with most cradle/bay style chargers. Relying on the protection circuit, like you mentioned, is never a good idea. By having a meter handy, it saves alot of guesswork.



True .. are there standard recommendations for inexpensive multimeters for beginners, or is quality such that most will do?

An alternative question: my only way to measure voltage is using the voltmeter that's part of my Cottonpickers charger. Any reason that that's not enough?


HJK: thanks, added the graph


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## Joe Talmadge (Dec 26, 2011)

*Re: Feedback requested: Li Ion beginner primer*

I added a slightly more detailed section on charging, A BIT MORE DETAIL ON CHARGING


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## N162E (Dec 26, 2011)

*Re: New section added 12/26/11: Li Ion beginner primer*



Joe Talmadge said:


> 12/26/11: Added A BIT MORE DETAIL ON CHARGING, after the charging section
> 
> There are multiple battery chemistries for *Li Ion *batteries. I am going to almost solely discuss *LiCo*, but there are other chemistries popular in lights such as *IMR* and *Lifepo4*. I will contrast with *IMR* occasionally.


I always love "Beginner Primers" full of confusing acronyms.


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## Joe Talmadge (Dec 26, 2011)

*Re: New section added 12/26/11: Li Ion beginner primer*

Heh, I see your point. That said, does knowing what "IMR" means really enhance readability and clarity of the document? I was reasoning that I'd just use the terms they'll be seeing as they do further research (and likely have seen already as they read through the forums), and knowing what the M in IMR stands for may not be as enlightening as knowing some of the characteristics of an IMR cell. A bunch of beginners on two forums seem to think this is clear as-is. I'm not necessarily being argumentative here, it would take me 60 seconds to whip up some definitions. I'm asking, if you're a beginner, does knowing what IMR stands for have any effect on the clarity of the document or its recommendations?


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## HKJ (Dec 26, 2011)

*Re: New section added 12/26/11: Li Ion beginner primer*

Maybe you need to add something like:






Without the supported column, but with an explanation of the abilities of different chemistries.


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## N162E (Dec 27, 2011)

*Re: New section added 12/26/11: Li Ion beginner primer*



Joe Talmadge said:


> Heh, I see your point. That said, does knowing what "IMR" means really enhance readability and clarity of the document?


Absolutly. When acronyms are used over and over again with no definition it makes for confusing and awkward reading. How hard is it to spell them out the first time around? What does Lico, IMR and life4pos or whatever stand for? I don't know and I've been here almost as long as you. I do applaud your importance placed on safety.


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## Joe Talmadge (Dec 27, 2011)

*Re: New section added 12/26/11: Li Ion beginner primer*

OKay, will add some clarity to the different chemistries at the top, maybe in table form as HKJ suggestd


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## N162E (Dec 27, 2011)

*Re: New section added 12/26/11: Li Ion beginner primer*



HKJ said:


> Maybe you need to add something like:
> 
> 
> 
> ...


Specs are nice but, what do the abbreviations spell? ICR, IMR, IFR (Maybe Instrument Flight Rules) LICo2, LIMn and lifepo4.


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## samgab (Dec 27, 2011)

*Re: New section added 12/26/11: Li Ion beginner primer*

Your own paraphrased version of these two tables might be helpful:









The information drawn from these tables was taken from the book: _Batteries in a Portable World - A Handbook for Non-Engineers, 3rd Edition_, by Isidor Buchmann


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## HKJ (Dec 27, 2011)

*Re: New section added 12/26/11: Li Ion beginner primer*



N162E said:


> Specs are nice but, what do the abbreviations spell? ICR, IMR, IFR (Maybe Instrument Flight Rules) LICo2, LIMn and lifepo4.



The ICR, IMR, IFR are not abbreviations, but a coded letter system, see http://www.candlepowerforums.com/vb/showthread.php?317698-Lithium-IMR-vs-ICR-vs-IFR for more explanation.
The LiCo.. etc. is standard chemical nomenclature, you can find them in a table of the periodic system.
Generally I do not believe that it matters what these names stands for, but more what is the ability of the cells behinds these names.


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## N162E (Dec 27, 2011)

*Re: New section added 12/26/11: Li Ion beginner primer*



Joe Talmadge said:


> OKay, will add some clarity to the different chemistries at the top, maybe in table form as HKJ suggestd


TThank you Joe.


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## N162E (Dec 27, 2011)

*Re: New section added 12/26/11: Li Ion beginner primer*



HKJ said:


> The ICR, IMR, IFR are not abbreviations, but a coded letter system, see http://www.candlepowerforums.com/vb/showthread.php?317698-Lithium-IMR-vs-ICR-vs-IFR for more explanation.
> The LiCo.. etc. is standard chemical nomenclature, you can find them in a table of the periodic system.
> Generally I do not believe that it matters what these names stands for, but more what is the ability of the cells behinds these names.


Maybe I'm just plain stupid, for sure not on a par with you genius' I guess I always thought that a "Beginners Primer" was supposed to answer questions not create them. You refer to the periodic table, I always thought that was elements, not mixtures or compounds.


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## HKJ (Dec 27, 2011)

*Re: New section added 12/26/11: Li Ion beginner primer*



N162E said:


> Maybe I'm just plain stupid, for sure not on a par with you genius' I guess I always thought that a "Beginners Primer" was supposed to answer questions not create them. You refer to the periodic table, I always thought that was elements, not mixtures or compounds.



I am not writing this primer, but just tries to fill in until Joe get it organized in the primer.
Look at the upper/lower case letters: Li, Co, Mn, Fe, all of them can be found in the periodic system, the number specifies how much of that elemental is used (It is a chemical formula). This specification does only cover the positive electrode (Cathode) in the battery, but getting into much more chemistry is way beyond a primer.


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## Viper715 (Dec 27, 2011)

Periodic table reference refers to the LiCo
If you separate it 
Li=Lithium
Co=Cobalt
So you have a lithium cobalt battery chemistry.

Edit; beat me to it and better explanation.


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## samgab (Dec 27, 2011)

*Re: New section added 12/26/11: Li Ion beginner primer*



N162E said:


> Maybe I'm just plain stupid, for sure not on a par with you genius' I guess I always thought that a "Beginners Primer" was supposed to answer questions not create them. You refer to the periodic table, I always thought that was elements, not mixtures or compounds.



HKJ is correct. Anyone with very basic high-school knowledge of chemistry would recognise those symbols such as LiFePO4​; Lithium, Ferrum (Iron), (Phosphorus, + Oxygen 4) etc.
It seems that the role of this thread doesn't appear to be to teach basic chemistry, but rather a basic guide to how to use and treat li-ion cells and batteries.
The OP can correct me if I'm incorrect in that...

Edit: lol, both posts above beat me to it also


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## Joe Talmadge (Dec 27, 2011)

*Re: New section added 12/26/11: Li Ion beginner primer*

Okay, 12/27/11, I added some words to address battery chemistries and the use of a DMM. Notes as to where those sections are, are at the top of the primer. Thanks again for the help in making this better.




samgab said:


> HKJ is correct. Anyone with very basic high-school knowledge of chemistry would recognise those symbols such as LiFePO4​; Lithium, Ferrum (Iron), (Phosphorus, + Oxygen 4) etc.
> It seems that the role of this thread doesn't appear to be to teach basic chemistry, but rather a basic guide to how to use and treat li-ion cells and batteries.
> The OP can correct me if I'm incorrect in that...



The initial reason I wrote this, is because a number of times I've seen (mostly on other forums) an interaction along the lines of:
poster 1: what batteries do you run in that?
poster 2: I'm running 16340s
poster 1: what's that?
poster 2: Lithium rechargeables, same size as a CR123
Poster 1: cool, I'll pick some up and try them out. Those SchmuckFires on eBay look nice & cheap.

My concern was the number of folks walking into Li Ions who had no idea whatsoever of the risks -- and I don't blame them, chances are no other batteries they've dealt with expose the same risks, even the Li Ions in their laptop are (usually) managed by the hardware in that laptop and the charger, not managed by the user themselves. So I wanted to write something we could point brand new users at, in a short enough format to be digestable in a single sitting, that impresses upon them the risks of Li Ions, tells them the basics of good handling, and of course lets them know the advantages. Of course, once this is all written, it is an incredible temptation to go from a 2-page primer to a more detailed reference document, since it's nice to have all that info in the same place. And therein lied my concern about explaining what (say) IMR means. I've included it, but I really want to make sure that information isn't just a distraction, that the user can simply look up on their own as they get more advanced.


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## samgab (Dec 27, 2011)

*Re: New section added 12/26/11: Li Ion beginner primer*



Joe Talmadge said:


> Okay, 12/27/11, I added some words to address battery chemistries and the use of a DMM. Notes as to where those sections are, are at the top of the primer. Thanks again for the help in making this better.
> 
> 
> 
> ...



Cheers.
Maybe a bit about sizing conventions and nomenclature would be handy? Eg: 16340, 10440, 14500, 18650, 32600, 32900, and so on. About how it basically reflects the diameter and length, but not always exactly, there are tolerances either side of the exact measurements, plus extra length for a PCB in some cases. And also about how they don't always come with a button top, that some have tabs, or are just flat because they are designed for manufacturers to task in battery packs.


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## Joe Talmadge (Dec 27, 2011)

*Re: New section added 12/26/11: Li Ion beginner primer*

Yes, really good info.

Okay, I'm getting some feedback about the issue I was concerned about -- mission creep of the primer from an easily-digestible raw-beginner how-to, to something a bit more detailed and usable as a reference. If I get more feedback like that, I'm going to re-structure the document in two parts: part 1, which has the most critical & basic beginner information, and part 2, which handles a lot of what we've been discussing this week regarding abbreviations and chemistries, the detail on what the numbers mean, etc. What do you all think?


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## samgab (Dec 27, 2011)

Joe Talmadge said:


> Yes, really good info.
> 
> Okay, I'm getting some feedback about the issue I was concerned about -- mission creep of the primer from an easily-digestible raw-beginner how-to, to something a bit more detailed and usable as a reference. If I get more feedback like that, I'm going to re-structure the document in two parts: part 1, which has the most critical & basic beginner information, and part 2, which handles a lot of what we've been discussing this week regarding abbreviations and chemistries, the detail on what the numbers mean, etc. What do you all think?



Personally, I think that is a great idea. 
You could have both parts as a single post in the first post of the thread, with a horizontal rule line dividing parts 1 and 2. 
So basic info, then scroll down for more detailed info about cell chemistries and charts and tables and whatnot.


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## N162E (Dec 27, 2011)

*Re: New section added 12/26/11: Li Ion beginner primer*



Joe Talmadge said:


> Okay, 12/27/11, I added some words to address battery chemistries and the use of a DMM. Notes as to where those sections are, are at the top of the primer. Thanks again for the help in making this better.


Hi Joe, You mention DMM as "DMM (Digital Multimeter)" Why not "LiCo (LithiumCobalt)" or "LiFePo (Lithium Iron Phosphate)" I've been out of high school almost 50 years I guess that makes me old fashioned but, why is something this simple have to be so difficult. I don't think searching a periodic table is simpler than adding a few words as a definition. Once again I applaud (?) your caution warnings.


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## snakyjake (Dec 28, 2011)

*Re: New section added 12/26/11: Li Ion beginner primer*

I'm confused by the statement:
"Safe chemistry, so is not available with a protection circuit. But that means the consumer must guard against overcharge and overdischarge themselves."

If it is safe, then why do I need to guard? I wouldn't be telling someone it is safe if there is still a risk of explosion/fire.

I thought all lithium-ion batteries are the same when it comes to over dis/charge safety risks.

I've also been curious how dangerous a lithium-ion battery is when overdischarged. I would assume there isn't enough energy from a discharged battery to be very dangerous, but maybe it doesn't take much.


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## samgab (Dec 28, 2011)

*Re: New section added 12/26/11: Li Ion beginner primer*



snakyjake said:


> I'm confused by the statement:
> "Safe chemistry, so is not available with a protection circuit. But that means the consumer must guard against overcharge and overdischarge themselves."
> 
> If it is safe, then why do I need to guard? I wouldn't be telling someone it is safe if there is still a risk of explosion/fire.
> ...



The OP is correct. Chemistries such as LiFePo4 are relatively safe. You need to guard against over-charging or over-discharging - not because of hazardousness of the cell - but because either of those states can reduce the life of the cell.
So the purpose of guarding against over-charging/discharging is not for the protection of the user, but for the protection of the life of the cell in those cases.
Not all lithium-ion cells are the same in terms of safety.

With LiCoO2 for instance, the danger involved in over-discharging is not necessarily immediately when the cell is discharged. The danger is because copper shunts can begin to form internally, shorting the cell out. These shunts may not short immediately as they may take time to form. But they could short at an unknown time in the future, perhaps when the cell is fully charged and inside a piece of equipment, or when it is on the charger, etc.


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## snakyjake (Dec 28, 2011)

*Re: New section added 12/26/11: Li Ion beginner primer*

I'd also mention:

1) LiNiCoO2.

2) Anti-expolsion vent/PTC module provides an added layer of protection against gas build-up in addition to the PTC thermal protection. Unlike regular vents used by most Li-Ion cells, these modules actually stop the action by separating the electrodes inside the battery when the pressure reaches a preset threshold. The vent disc will open and release the gas plus stopping the cell from further chemical reaction.

3) Heat Resistance Layer (HRL) technology that forms an insulating metal oxide layer between the positive and negative electrodes. The layer prevents the battery from overheating even if a short circuit occurs.


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## 45/70 (Dec 28, 2011)

*Re: New section added 12/26/11: Li Ion beginner primer*

Just a note on "safe" chemistry Li-Ion cells. There are no "safe" chemistry Li-Ion cells. There are "safer" chemistry cells, such as LiMn and LiFe, with LiFe being the "safer" of the two. The difference between these two chemistries and LiCo cells is that they are _somewhat_ more tolerant to abuse. They require more extreme conditions before a "venting with flame" incident can occur. That said, there is at least one thread here on the Forums showing the charred remains of a LiFe disaster. The light was literally "toast" after installing discharged cells along with fully charged cells in series.

The "safe chemistry" slogan, I think is more of a marketing tactic than anything. All Li-Ion cells contain volatile solvents in their manufacture. It is these solvents that under the right conditions, will ignite and result in a "venting with flame" incident. There is more than one way this can be triggered, but the result is the same.

As far as the state of charge of a LiCo cell (I believe this applies to the other chemistries, as well, but not sure), if shunts have formed within the cell and there is enough power left to heat things up enough to ignite the solvent, then you have a potential problem, even with a basically, discharged cell.

Oxygen formation is one of the byproducts of a damaged Li-Ion cell, so heat (whether caused by internal short circuit, attempting to charge a damaged cell, discharging at a high rate, metallic lithium that has formed on the electrodes and begins to oxidize, or......), a volatile solvent, along with oxygen, is what creates the potential hazard in all Li-Ion cells.

Dave


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## Joe Talmadge (Dec 28, 2011)

*Re: New section added 12/27/11: Li Ion beginner primer*

You know, I'd toyed with the idea of using the term "safer chemistry", and avoiding the word "safe" anywhere. Perhaps I'll do that. In the advanced section, I'll talk a bit more about the possible failure modes, including the discussions we've had in this thread. It won't be until at least Thursday before I get to the revision, but I think we're circling in on the right information and the right format


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## snakyjake (Jan 6, 2012)

*Re: New section added 12/27/11: Li Ion beginner primer*

I'm trying to figure out capacity vs. safety: 
1) How much capacity I lose by going safer?
2) How much safety I'm gaining?

In this thread I'm hoping #2 can be answered. 
Is there a safety margin defined? 
What kind and how much more "tolerance" and "abuse" can they take? Are we talking the type of abuse from using construction tools? Or being left on the charger? Do our normal use of flashlights cause battery abuse?

45/70 mentioned "_somewhat_ more tolerant to abuse". But also says "require more extreme conditions..." I'm having troubles understanding "somewhat" meaning small, and "extreme" meaning a lot.

When I read Battery Junction's (BJ) safety description of IMR, the precautions looked identical to what I've read regarding LCO on the forum. BJ even said this about LCO: "Protected lithium rechargeable batteries are _very safe_..."

So I'm starting to draw the conclusion, for LED flashlights: All lithium-ion chemistries have the same risk. One battery chemistry is not safer than another. The "safer" definition regards to a different use, not LED flashlights. But I'm not sure if there are extreme high drain flashlights that people are using on the forum. Not sure what defines high drain either. 

So since I'm not using high drain LED flashlights, the "safer" chemistry doesn't apply?

Jake


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## 45/70 (Jan 7, 2012)

*Re: New section added 12/27/11: Li Ion beginner primer*



snakyjake said:


> 45/70 mentioned "_somewhat_ more tolerant to abuse". But also says "require more extreme conditions..." I'm having troubles understanding "somewhat" meaning small, and "extreme" meaning a lot.



Hi Jake. I think you took what I said out of context.

The attributes of both LiMn and LiFe cells are more forgiving than those of LiCo or LiPo cells. The conditions I mentioned in my previous post under which a "vent with flame" incident is likely to occur, require more extreme conditions with LiMn and LiFe cells.

For example, the temperature at which oxygen formation occurs, is higher with these cells, as compared to LiCo/LiPo. This means that under abusive conditions it will take longer and/or the current level will be required to be higher, for an incident to occur. Thus these two chemistries are in fact _somewhat_ safer. However, if the limits are pushed to the max, a vent with flame incident can still occur. So again, there really are no "safe" chemistry Li-Ion cells, just _somewhat_ _safer_.

Protection circuits which have been added to manufacturer's LiCo Li-Ion cells by third parties, are a matter for another discussion. The question here is, will they even work. Was the protection circuit added to the cell designed for your specific application? Does your application typically draw 20ma of current, or 5A? Protection circuits added to cells can't do both, at least not with any certainty. This is why the common comparison of protection circuits used in laptops, and those added to LiCo cells for use in a wide variety of our lights, is non sequitur. The PCBs added to LiCo cells are a "catch all" and cannot cover every possible usage scenario. They are installed as a last resort to help prevent an "incident", and should not be relied upon.

Dave


----------



## snakyjake (Jan 7, 2012)

*Re: New section added 12/27/11: Li Ion beginner primer*

Hi Dave, thanks for the reply. I'm still trying to find the "context" in an internet forum conversation, and respect the many posts you've made on the subject.

I'd like to understand more about the "abusive conditions" context. Is that like construction power tools, or constantly over-discharging our single bulb lights?

This brings up the next question... 

The "abuse" I commonly hear about is over-discharging, unbalanced mutli-cell, over-charging. Over-discharging is my #1 concern, as it takes the most user effort to monitor (and I never do it, and rely on protection circuit). I use singe cell lights and high quality charger to mitigate the other risks.

So does "safer" mean chemical abuse (i.e. over-discharging)? Or only physical (construction power tools) abuse?

Jake


----------



## loquutis79 (Jan 22, 2012)

*worried about 18650's*

So being new to this world of high lumin flashlights, and spending the last few weekends reading stuff in these forums [great info. by the way] my head feels like it is ready to go the way of the exploding batteries I keep reading about.
Right now I am running CR123a primary batteries in both my Fenix TK35 and TK21. The first set of primay's in my TK35 were tossed as soon as I lost my turbo level of light. That was my signal that they were getting weaker. Taking no chance, and having no single cell light, I got rid of them and put in a new set.
I am now thinking of switching to AW 18650's knowing what future costs of primay's will add up to.
Here is my question, or one of many to come, and I hope it has not been covered before as I did have a quick look.
Why are laptops not exploding all over the world. I mean alot of laptops. Most people I know have them plugged in day and night with no event of venting. Or they run them down until they are empty before charging with no need to put a DMM on them[or no way of doing so] These are the same laptop units that I keep reading about in these forums, where people are harvesting some of their 18650's from.
I will take precautions. I will buy what Fenix is offering right now, the Ultrafire WF 139 and later get a Pila. The Ultrafire charger is coming with AW 18650 3100 mAh batteries. I have a DMM which I will use, don't need the ZTS tester for these I believe?? I will pull the cells as soon as the light is green to cover my rear until the Pila is here.
I trust this is somewhat of a safe approach.
But why, oh why, are laptops not exploding?
Thanks guys.


----------



## LEDAdd1ct (Jan 22, 2012)

*Re: worried about 18650's*

A few thoughts from someone who is admittedly not an electronics expert:

1) The battery packs aren't truly being run down. The software/firmware on the OS and in the battery pack don't let you fully discharge the pack. There is a buffer. Take a bare, unprotected cell and put it in an LED light with flat regulation and no overdischarge protection and let her rip. Different story.

2) The dangers of lithium cobalt cells are very well documented on CPF, and that may make people fearful. You shouldn't be. Prudence is key. If you are ready to drop primaries and go 18650, here are my suggestions:

-buy cells from a trusted labeler (you already know who those are)

-use a quality charger (Pila IBC, cottonpickers, or hobby charger)

-don't run your cells down all the way

-don't store them in your furnace room or in a hot car

-when the cell gets weak/doesn't charge, recycle it

We have lots of members who use these cells without issue, and a few who do encounter problems. While there are no guarantees (in life or with batteries), doing the above will minimize the chances of trouble.

Again, I am not an expert in this area, and the above suggestions are just what I have gleaned from speaking with those who do know their stuff in and out. I am sure others will chime in. 

Good luck!


----------



## 127.0.0.1 (Jan 22, 2012)

*Re: worried about 18650's*

IMHO

I found through searching CPF that some 18650 have the most reliable protection for cutoff at 20% capacity.
-they actually cut off as they should. other batteries tested in that particular round did NOT cut off depletion.

so even with protected batteries there is a lot of variance on the reliability of the protection circuit itself.

dig up some CPF articles and shootouts, make an informed decision. and YES get and use a nice little voltmeter to monitor all
your rechargables.


----------



## SilverFox (Jan 22, 2012)

*Re: worried about 18650's*

Hello Loquutis79,

Welcome to CPF.

There are at least three parts to laptop power safety.

The first is that they use quality cells.

Next the laptop has thermal monitoring added to the battery pack.

Third is the power management circuits that set charge rates and maximum and minimum voltage. Some even have a cycle count. The design engineers know that a battery is only good for so many cycles, so if you count the number of cycles you can eliminate problems by simply shutting the pack off after that many cycles have passed.

Let's compare this set up to using a single cell in a flashlight.

A quality cell is usually not the most inexpensive cell that can be found. Many are more concerned with price than with quality.

In laptop use, when the temperature goes up a fan kicks on to cool things down. Most flashlights just get hotter and hotter.

In laptop use the charger is built into the unit. The charge algorithm is designed to maximize the cycle life of the battery pack. If unusual high current draw is observed (a short), the monitoring circuit shuts things down. If cycle counting is used, the battery pack is shut down when it is close to its expected cycle life.

In flashlight use you pick a charger. Once again many are more concerned with price than quality, and a low quality charger may not take good care of the cell. With some chargers you also have the option to choose the charge rate. The charge rate you choose may not be the best charge rate for the cell. In a flashlight you may end up over discharging the cell. All of these variables can subject the cell to abuse, and that can lead to problems. The battery pack in the laptop makes an effort to control all of these variables so that it won't catch on fire.

In addition, many people feel that as long as a cell can store any capacity at all, it is still good. This compounds the danger because as a Li-Ion cell ages the electrolyte oxidizes and becomes more unstable. Continuing to use a cell that is not "healthy," amplifies the possibility of having a "rapid venting accompanied with flame" event.

When a Li-Ion cell has dropped below 80% of its initial capacity, it is time to recycle it.

These are just a few of the differences between laptop use and flashlight use. Another thing that comes to mind is physical abuse. Most people take extreme care not to drop their laptop. The same can't be said for flashlight use.

In an effort to bring some degree of safety to flashlight use, some offer a protection circuit that has been attached to the cell. This protection circuit protects against GROSS over charge and over discharge, and usually has a maximum current limit. It offers some protection, but it is not as good as the management circuit built into laptops.

The bottom line is that laptops don't explode because they have a power management circuit that takes good care of the battery pack, and they use quality cells. If you take the same precautions with flashlight use, the cells used with flashlights will not explode either. (As a footnote, these cells don't explode, they rapidly vent, sometimes with flames...)

Tom


----------



## 45/70 (Jan 22, 2012)

*Re: worried about 18650's*



loquutis79 said:


> Why are laptops not exploding all over the world. I mean alot of laptops......
> 
> But why, oh why, are laptops not exploding?



Hi loquutis and welcome to CPF!:thumbsup:

I see reference to this quite often. What most people don't realize is that the protection circuitry built in to laptops and other consumer devices that utilize various types of Li-Ion battery packs, are designed for that specific device and it's associated current demands.

The best we flashaholics can do to simulate this type of protection, is purchase cells with a protection PCB that has been added onto the bottom of the cell by a third party, or only buy lights that have their own built in protection circuitry. The later, which is really the prefered method, in all cases I'm aware of, is only effective with single cell lights, however.

As for protection circuits added to individual cells by third parties, these circuits by necessity, have to cover a wide range of potential operating conditions. Will the cell be used in a light that draws 20mA, or one that draws 5A? The protection circuit added to the cell can't really do both effectively, so a compromise has to be made.

Also, there is the quality of the components used and the construction of the protection circuits. Some are made with precision and from quality components, others, maybe not. 

Li-Ion cell manufacturers do not supply Li-Ion cells at the consumer level, nor do they manufacture protection circuits. Protection circuitry is normally provided by the device, or battery pack maker, and proof of such is required before a Li-Ion cell manufacturer will provide them with cells. This is for liability reasons. So, protection circuits that have been added to individual cells is one point where a compromise has been made concerning the safety level of our lights.

In many cases (more than likely most), the individual, or "loose" as they are called, Li-Ion cells that we purchase for use in our lights are bought up as "factory seconds" that for one reason or another were deemed not useable for the manufacturing of battery packs by the manufacturer of the cells.

The last I was aware of, there is a worldwide shortage of, in particular, 18650 size Li-Ion cells, for use in the making of battery packs for laptops and other consumer products. If you search the net, you will find many trading companies, mostly in China, offering name brand Japanese and Korean 18650 cells in large quantities (eg. 1000+) from companies such as Sanyo, Samsung, Panasonic, LG, and others. With this worldwide shortage of 18650 cells, you have to ask yourself, where did these cells come from? And, who do you suppose buys them?

Many of the Chinese Li-Ion cell distributors (not manufacturers) actually relabel recycled cells, as well as those obtained from battery packs that were involved in a "recall" for whatever reason. Most of these companies go by some sort of "Fire" brand name, such as "CrapiFire", or BangiFire, or some such other nonsense name that plays upon the U.S. based SureFire company name. At any rate, here we have yet another drop in the potential safety level of the cells we obtain. Some might be just fine, but others.....?

The best we can do is buy cells from a reputable source. Due to the higher cost of quality cells, and better components used in the protection circuits (if added), cells from these distributors are going to carry a higher price. Top tier cells (whether "seconds", or not) no doubt cost more than lower quality cells, or those obtained from recalled or recycled battery packs, so the distributor/dealer has no choice but to pass this additional cost on to the buyer.

So anyway, you can't really compare the cells and associated protection circuitry used in our hobby, to those used in laptops, or any other consumer device. There are just too many potential variables for a comparison.

*EDIT:* I see that in the time it took me to write this up, Tom posted. Oh well, the more the merrier. 

Dave


----------



## loquutis79 (Jan 22, 2012)

*Re: worried about 18650's*

Ok, I will buy that. I will still make sure I take all the precautions that I have read here.

My other question, and I hope it is ok to ask in the same tread is, if I order the Pila IBC 4 Stage which I intend to, will it take AW 18650 3100mAh batteries? Is the diameter and length of this cell going to fit and charge properly? I have a local supply of AW 18650 3100mAh and as they are touted to be one of the best I would like to stick with these.

And what will give me a brighter, longer lasting light in my Fenix TK35 and TK21, primay's or the 18650's?


----------



## rick458 (Jan 23, 2012)

*Re: worried about 18650's*

tagged for reference


----------



## loquutis79 (Jan 24, 2012)

*Re: worried about 18650's*

Just wondering what "tagged for referance" means.
Did I post something wrong?


----------



## rick458 (Jan 25, 2012)

*Re: worried about 18650's*

No you Didn't
I wanted to follow this thread so i put a short response on it
But I SHOULD have just used tools to subscribe to it


----------



## c.joe (Jan 25, 2012)

*Re: worried about 18650's*

Great info guys.

So when you guys say not to "run it down" does that mean leave your light on until it dies, leaving your battery sitting on your shelf forever, or in your flashlight?

Is it safe to leave it in a protected charger? Say I'm using one for a month or so while I have another 18650 waiting in the charger to switch out. Is this safe?

Should I always discharge after use?

Thanks!


----------



## snakyjake (Jan 25, 2012)

*Re: worried about 18650's*



c.joe said:


> So when you guys say not to "run it down" does that mean leave your light on until it dies, leaving your battery sitting on your shelf forever, or in your flashlight?
> 
> Is it safe to leave it in a protected charger? Say I'm using one for a month or so while I have another 18650 waiting in the charger to switch out. Is this safe?



For a RCR123, don't let it go below 2.75v. Don't overcharge it above 4.20v. This might be the same for 18650 if using the same chemistry.



> Should I always discharge after use?



I don't want to charge the battery too many times, and lessen the life. I also keep my batteries stored fully charged.

I rely 100% on the protection circuit and charger. But others don't trust a circuit. I've never read any tests done on protected circuits, so am unsure how much to trust it. I might be asking for trouble at some point when my cells get old.

Jake


----------



## RBWNY (Jan 25, 2012)

*Re: worried about 18650's*

_""So when you guys say not to "run it down" does that mean leave your light on until it dies, leaving your battery sitting on your shelf forever, or in your flashlight?

Is it safe to leave it in a protected charger? Say I'm using one for a month or so while I have another 18650 waiting in the charger to switch out. Is this safe?""

_If your question is pertaining to protected cells... the circuit(s) will normally kick-in...around 3 for an RCR and 3.6 for a 18650. Do not leave a cell sitting in the Pila (plugged-in) until you need it. They should be removed reasonably soon after the charge light turns green.


----------



## vinny (Jan 25, 2012)

*Re: worried about 18650's*

I too was once worried about 18650's that i was using in a rop low maglite, The only thing i can recommend is aw imr 18650's, they dont have protection circuits because they are quality cells that use safe chemistry, yes there more expensive than firexxx branded cells but in my opinion id rather have peace of mind than a possible pipe bomb in my hand.

Vinny.


----------



## Rees (Jan 25, 2012)

*Re: worried about 18650's*

I think that reading stories of these going bad has stopped me from jumping on the 18650 bandwagon, but i've been researching what I can about them and seeing what would be the safest setup I can use. Another question about 18650 charging ive really have been able to find is if its safe to use the pila charger and put into something that could contain a meltdown like a metal tool box or something.


----------



## snakyjake (Jan 26, 2012)

*Re: worried about 18650's*



vinny said:


> The only thing i can recommend is aw imr 18650's, they dont have protection circuits because they are quality cells that use safe chemistry...



IMR is not "safe" chemistry and can still explode. Protected lithium-ion is the safest lithium-ion battery for flashlight use.

The safe rechargeable chemistry for flashlights is NiMH.


----------



## hellokitty[hk] (Jan 26, 2012)

*Re: worried about 18650's*



snakyjake said:


> I also keep my batteries stored fully charged.


They'll degrade fast if you leave them like that.


----------



## 45/70 (Jan 26, 2012)

*Re: worried about 18650's*



c.joe said:


> So when you guys say not to "run it down" does that mean leave your light on until it dies, leaving your battery sitting on your shelf forever, or in your flashlight?



Any one, or all of the above. If the cell discharges below a certain voltage, cell damage will occur. This is permanent damage and cannot be reversed. Depending on the manufacturer and the particular cell, damage begins to occur to LiCo/ICR Li-Ion cells at somewhere below 3 Volts OC (open circuit voltage). A LiCo cell is considered "dead" at about 3.50 Volts OC. From this voltage level it really doesn't take very long for the cell to drop below 3 volts, for whatever reason, as there is very little capacity left.

Also, a note on protection circuits that are added by third parties to loose LiCo Li-Ion cells, such as we use in our lights. These protection circuits, unlike the circuitry built into a laptop, or cell phone, are added as a last resort in order to prevent catastrophic failure of the cell when recharging, not to remind the user that it is time to recharge the cell.

The protection circuitry in laptops and such warn the user (or shut the device down) at a much higher level of remaining charge, than the PCBs added to loose cells. While it may be safe to run a cell down until the protection circuit trips (provided, the protection circuit actually works), in many cases, the cell has already been damaged to some degree. This is why it is not recommended to run cells down until the protection circuit trips, on a regular basis.



vinny said:


> I too was once worried about 18650's that i was using in a rop low maglite, The only thing i can recommend is aw imr 18650's, they dont have protection circuits because they are quality cells that use safe chemistry



As Jake said above, IMR chemistry cells are not really "safe" and actually, running IMRs instead of protected ICR cells, increases the chance of cell damage. And while IMR cells are considered "safer" than unprotected ICR cells, they still have their limits, and can be a safety concern. It just requires a bit more abuse for IMR cells to "vent".

Again though, unless you monitor cells very closely during discharge, you are more likely to damage IMR cells due to over discharging, or cell reversal, as they do not include protection circuits.

Dave


----------



## space-cowboy (Jan 26, 2012)

*Re: worried about 18650's*

Well,

When it comes to the safe levels of charge and discharge of 18650 cells - things are "little" bit more complicated.

What about Panasonic cells : for example NCR18650A 3100mAh that can be safely discharged (without protection) to 2.5V

Or

Samsung 3000mAh (LG too) model that needs to be charged (for full charge cannot be charged with standard charger) to 4.35V to get fully charged?


And these are best of the best 18650 cells.


----------



## Rees (Feb 10, 2012)

*18650s for beginners*

I want to get into using li-ion batteries but I didnt know what would be better to start with the protected aw's or the IMRs..My first light im going to use them in is my tk35 if that makes a difference.

Thread Merge - Norm


----------



## PapaLumen (Feb 10, 2012)

*Re: 18650s for beginners*

The protected AW's will be fine. The IMR's are not protected (but are safer than normal li-ion) and meant for high current devices but at the cost of capacity.


----------



## Joe Talmadge (Feb 11, 2012)

*Re: 18650s for beginners*

I tend to default to protected LiCo/ICR, unless I know that IMR is needed to handle the current requirements, or the flashlight has its own low voltage circuit. Otherwise, it's not worth having to monitor the IMR's voltage.


----------



## Rees (Feb 11, 2012)

*Re: 18650s for beginners*

Since I was looking at the AWs 3100mah, should I get some of light hounds magnet spacers for versatility?


----------



## HKJ (Feb 11, 2012)

*Re: 18650s for beginners*



Rees said:


> Since I was looking at the AWs 3100mah, should I get some of light hounds magnet spacers for versatility?



Magnets are not a good idea, they can short things out. If you have some lights that cannot use flattop batteries, get some batteries with button top.


----------



## grndslm (Feb 23, 2012)

*Re: 18650s for beginners*



HKJ said:


> Maybe you need to add something like:
> 
> 
> 
> ...


This should *definitely* be included in the OP... so that people actually understand their charger must support a variety of Li-Ion battery types! ... or at least the one(s) that they have already or are planning to purchase.



HKJ said:


> Magnets are not a good idea, they can short things out. If you have some lights that cannot use flattop batteries, get some batteries with button top.


This should definitely be the *first* thing in the " RECOMMENDATIONS FOR BEGINNER SETUPS" section. Consider adding _"I don't trust the *Fire batteries, except people have had decent luck with the TrustFire 'Red Flamers' (SKU #.....)"_

I would also move this "Recommendations..." section immediately below the "LI ION BATTERY CHEMISTRY AND SAFETY" section.

Then *most definitely, *toss out everything above "Why go with Li-Ion?"

At that point, I think you'll have a lot more people not only _willing_ to read, but also _able_ to read. The recommendations shouldn't be hidden at the bottom, past information that BUYERS don't care about. Everybody here is a BUYER; not everyone here is an ENGINEER, or even a "member" of this forum who cares to know why or why not there shouldn't be a primer.


----------



## SoCalDep (Feb 24, 2012)

*Re: 18650s for beginners*

I consider myself a beginner...maybe not even a that level. I have numerous lights, and have toyed for some time with getting into using Li-ion batteries, but confusion regarding charging (over-charging, over-discharging, fires, initial charged vs working voltage, etc.) has really kept me away. I'm currently running eneloops in my Quark AA Tactical because they were easier to understand. 

I had no problem understanding the point and content of this primer, and now feel very comfortable regarding what is needed to choose appropriate batteries (electronically*** more on this in a minute) for a device and how to charge and maintain them safely.

Though I'd love answers to my following questions, I list them more for informational purposes as someone who read the primer and still has questions before making the "plunge" to order batteries/charger/etc:

I now "get" when I would want to select LiCo (protected) vs IMR cells based on the requirements of the light. I can search or ask questions to make selections for a specific light. I am still a little confused about safe/appropriate voltages. I see my Quark was designed for up to 4.2 volts, so I'm pretty sure there is no problem using protected LiCo batteries. I'm considering purchasing a Lumapower Trust Model-1. The listing shows it will work with a 3.7 volt Li-ion. Would I need to allow the battery to "rest" and drop in voltage before use? If the battery comes off the charger at 4.2 volts will it damage a light designed to work at 3.7v? If so, is there a way to target-charge these batteries to 3.7v or are there batteries more appropriate to a 3.7v light? I know the "working voltage" of many Li-ion batteries are 3.7v but I'm still confused as to how that relates to the 4.2 volt charge and thus possible problems. Sorry for the potentially dumb questions, but I think my stupidity may actually be your target audience  .


----------



## Joe Talmadge (Feb 25, 2012)

*Re: 18650s for beginners*

Hi guys,

Thanks much for the feedback. I'll take another run at this over the next week or so and re-post. 

Just to give you my frame of mind, I do think more folks are like SoCalDep -- like and appreciate diving a bit deeper. I want to make sure that someone who would like to understand the fundamentals can get them in the primer, or at least figure out where to go next. And I don't believe you need be an engineer to understand what I wrote.

I do, however, want folks like grndslm who don't want to go so deep, and find that info distracting, to also get enough out of the primer. For that reason, I'm going to do a better job of dividing the primer into beginner and next-level sections. I am pretty firm that there's a minimum amount of info that MUST be shared. If I were teaching someone how to use a gun, and they asked me "just tell me which gun and which bullets to buy, so I could get to the shootin', I'm just a buyer and shooter", I'd pass on teaching them at all, because without some very base-level knowledge, that person could be a danger to himself and others. Obviously, Li Ion batteries aren't quite in the same league, but nevertheless, they can be a serious risk if mis-handled, and I am still going to try to get people to read through the "charging" and "discharging" sections before they get to the recommendations. But, with some of the more technical stuff moved to a "more advanced" section that comes later, I hope grndslm will find it easier going and more satisfying.

SoCalDep: to answer your question directly, I'm afraid people are sloppy about how they talk about Li Ion batteries. Sometimes they talk about max voltage off the charger (4.2V), sometimes they talk about nominal voltage (3.7V), and they're talking about the same batteries. That causes the confusion you ask. Without knowing anything about the Lumapower, I can almost guarantee you that if they talk about 3.7V Li Ion, they mean you can run standard LiCo or IMR batteries in them, they're talkng about nominal voltage. But, until you're very confident in the technology, I'd encourage you not to accept an answer from any one source, including me. If you ask on Lumapower's forum in the cpf marketplace, you'll get an answer right away. Ditto in the LED section here, etc.


----------



## grndslm (Feb 27, 2012)

*Re: Li-ion beginner primer*

I've written a number of guides, and they all start out with basic, bullet-point concepts. For example...



> INTRO
> ====
> - Lithium batts rock & roll... but if mistreated, they can potentially explode in a flashlight like a pipe bomb.
> 
> ...



Sometimes the bulletpoints start to turn into sentences and paragraphs, but a lot of times they're just left like they are. Much easier to get the point, if ya know what I mean. :wave: Your guide mostly looks like this, but I would at least make the MUST KNOWN INFO as easy to read as possible, which means that section should be ALL bullet points.

Just MHO, of course. :thumbsup:


----------



## Joe Talmadge (Feb 28, 2012)

*Re: Li-ion beginner primer*

Yes, I've done one or two of these myself also  I do agree that some bullet lists are useful, and the new version with the split beginner/"advanced" sections has a bit more of this at the end of the beginner section. Although I like your idea -- maybe a bulleted list at the end of every section would help too, I'll try that. Again, though, you and I just disagree on the overall approach. The metaphor is imperfect, but it's the best way to make my point: I wouldn't write a beginner's shotgun shooting guide with simple bulleted summarized lists up front, because I think it's important that some fundamental concepts be grasped, to ensure everyone's safety. I feel exactly the same way about Li ion batteries, and while I want a beginner to be able to read just a couple of pages and get what they need, I don't want to teach a shotgun shooter who just wants to know which shotgun and shells to get so they can "get to the shooting", while refusing to try to understand the basic concepts, and I think you're in a similar space when it comes to Li Ions. Good luck to you, but I really want most people who read the primer to walk away with some basic understanding of the most fundamental concepts, not just compatibility etc.

I'll post an update by this weekend, with the split and summarized lists, and see how it looks...


----------



## ChrisGarrett (Feb 29, 2012)

*Re: Li-ion beginner primer*

You might want to add something more about storage. I've read that storing a Li-ion cell fully charged in not a good thing, so dropping it down to ~3.9v, or a bit less, is preferable. I don't recall where I read that here, but if it's true, add something about that.

Also, we need to give a ballpark definition to long term storage. Does 'LTS' equal 3 months with Li-ion, 6 months, a year?

Also, in the same thread I read that people store their Li-ions in the refrigerator, but not the freezer, for optimal longevity?

Thanks, Chris


----------



## snakyjake (Feb 29, 2012)

*Re: Li-ion beginner primer*



> The thing about LiCo batteries is that the chemistry is not safe. By not safe, I mean, conditions can occur where the battery goes into thermal runaway, at which point it can vent violently or explode. A safer battery chemistry might cause the battery to shut down under these conditions, but because LiCo batteries go into runaway, I am only going to be discussing protected batteries from here on out: those batteries with built-in protection including a protection circuit and other safeguards that shut the battery down and prevent other conditions that can cause problems.



I found this statement to either be confusing or misleading. Isn't it true *all* lithium-ion batteries can experience thermal runaway?
Does a "safer battery chemistry" really shutdown the battery? I thought it was the protection circuit that did that.

It seems to me IMR and IFR can also go into thermal runaway, explode, and are not protected from doing this like protected LiCo. The difference I see between IMR/IFR and LiCo is that it takes 482ºF to runaway, instead of 302ºF, and IMR/IFR has nothing to prevent a thermal runaway. Sure seems to me for the vast majority of flashlights, protected LiCo is safer than IMR/IFR.

The primer is good regarding lithium-ion batteries in general, but the primer doesn't prime us for flashlight usage of lithium-ion. I doubt IMR/IFR offer any advantages over protected LiCo in flashlights. If you leave your flashlight running on IMR/IFR, the battery is subject to damage. On the other hand, a protected LiCo will shut down before the damage. This assumes the protection cell shuts down the battery, and I have never read a post where a protected LiCo cell malfunctioned. Just think how easy it is for some lights to be switched on, and run themselves down.

I'd also like to see lithium primaries added for comparison. Primaries aren't safe either (i.e. mismatched primaries in series shorting out), and I think that point needs to be abundantly clear.

Jake


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## brted (Mar 1, 2012)

*Re: Li-ion beginner primer*

Threads like this are why wiki's are so much better for storing information (and why I started the flashlight wiki). Somebody can put together the information and other people can edit, correct, or add as needed. People can discuss things on a discussion page if need be. And when there is new information *anyone* can add to it, not just the OP. If you need to have a long technical analysis but don't want to sidetrack the main article, it can be put on a separate page with a link to it.

There is some great information in this thread, but it is already spread out over 58 posts. My two cents. I do think there is some great info here.


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## hank (Mar 1, 2012)

*Re: Li-ion beginner primer*

This was news to me:

"With LiCoO2 for instance, the danger involved in over-discharging is not necessarily immediately when the cell is discharged. The danger is because copper shunts can begin to form internally, shorting the cell out. These shunts may not short immediately as they may take time to form. But they could short at an unknown time in the future, perhaps when the cell is fully charged and inside a piece of equipment, or when it is on the charger, etc. "


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## stickydoorknob (Oct 14, 2012)

*Re: worried about 18650's*

thanks, very helpful advice.


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## Shadowww (Oct 14, 2012)

*Re: worried about 18650's*



snakyjake said:


> The safe rechargeable chemistry for flashlights is NiMH.


Also LiFePO4 (18650 cells from A123Systems and Samsung, 26650 cells from A123Systems).


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## -Falk- (Nov 22, 2012)

*Some questions about different brands of 18650 batteries*

I have read and heard about exploding\popping or malfunction, smoking, burning flashlights (also chargers burning down houses when charging batteries). But I have some questions, I get the impression that it is usually cheap batteries and people who fail in using multimeters and do other bad things (or not doing the right thing) with there cells that this is happening to. But my question is, is there any cases where a 18650 panasonic cell has made an explosion or taking fire? even with neglect? I know AW cells are regarded as very safe cells, but what about other brands like Keeppower, Orbtronic, AmpMax, Enerpower, EagleTac, RediLast, Callies Kustom and Xtar? Have there been any reports of accidents with any of these brands recorded? And another quick question, when using a flashlight with multiple batteries in one flashlight, what are the chances of something goes wrong even if you should use a cheaper brand of batteries (like Trustfire/Ultrafire) if you treath them right (including using same brand only together, using a quality charger etc) and regularly monitor their health with a multimeter?


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## naiter (Nov 27, 2012)

*Re: Some questions about different brands of 18650 batteries*

Great thread!
Questions I still had would be use with multi-cell lights.


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## arjay (Feb 11, 2013)

*Help with Li-ion Batteries*

Hello Everyone, I'm an old member who has dropped off the Flashlight scene for 2 years now. I just popped my head up and boy has the Flashlight scene changed. I've been reluctant to jump onto the Li-ion bandwagon a couple years back for fear that they have yet to fully mature. Looking around I see that Li-ion batteries are the future and a lot of brands are embracing them. I'm looking for upgrades and think I'm about ready to hop on but have no clue where to start. I have a couple of questions that I hope the gurus here can answer for me. I plan to invest on the system, multi-cell/single cell lights, chargers and batteries. 

1. Are Li-ion cells safe enough to use in multiples? (i.e. Tk75 w/ extenders with 12 18650 cells.)
2. Do I have to keep their voltages within a small tolerance or the protections will take care of that? (0.1v?)
3. What precautions do I need to take?
4. What 3400mah cells would you recommend? (read that Keeppower is the OEM producer of many name brands, last I remember was AW brand was the best 2 years ago.)
5. If I want the capability to charge 6-8 batteries at a time, what charger/s should I purchase? (something that has the right charging algorithm for Li-ion cells, 2 years ago was the Pila charger.)

Comments and suggestions are welcome, Thanks!


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## pinkpanda3310 (Feb 11, 2013)

*Re: Help with Li-ion Batteries*

This might help - http://www.fortbendrc.com/tips/LithiumBatterySecrets.pdf


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## snakyjake (Feb 11, 2013)

*Re: Help with Li-ion Batteries*

While weighing the benefits/risk, also read up on LiFePO4.


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## arjay (Feb 11, 2013)

*Re: Help with Li-ion Batteries*

Thanks for pointing me to the right direction, but it seems that only one of my question was answered. 

My biggest concern is with questions 1 and 2. Could someone please give me a definite answer. I'm worried that I might run the batteries down too much and one would reverse charge. I'm not sure if the protection circuit would kick in and cut power to the light. 

1. Are Li-ion cells safe to use in multiples? (i.e. Tk75 w/ extenders with 12 18650 cells.)
2. Do I have to keep their voltages within a small tolerance or the protections will take care of that? (0.1v?)


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## snakyjake (Feb 11, 2013)

*Re: Help with Li-ion Batteries*

Protection circuits will protect from short...if the protection circuit doesn't fail. I think protection circuits have been reliable; except for some cell phones, laptops, and a $32 billion dollar plane.

I'd rather use IFR/LFP and not worry about it. Plus my light won't cut-out like protected batteries. There's no way I want to manage 12 ICR's. 

The general consensus is that protected ICR isn't "safe"...but low risk. The question is how low is the risk? The answer is that no one knows, but most accept the tiny risk.


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## alexandrul (Feb 15, 2013)

*18650 maintenance questions*

I have recovered a few 18650s from laptop battery packs, and they are in various states of charge, ranging from 4V down to 0.16V (these ones are assumed dead and disposed of). Also, I can't tell for how long they have been stored.

Google helped me to find a 1.5V reference value, under which is dangerous to attempt charging. Another common reference is the 2.8V, which is the level that should trigger some form of protection. However, I have quite a few with 1.9, 2.1, and 2.25V which are in a somewhat gray area, and I have no idea at this point which ones are worth keeping.

So, what is the voltage limit under which a given 18650 should be discarded, assuming a storage periond of at least 3 months at that level?


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## SilverFox (Feb 15, 2013)

*Re: 18650 maintenance questions*

Hello Alexandrul,

The 2.8 volt reference you find is for a cell under load. When you remove the load and the cell is not connected to anything I like to see this "resting" voltage in the range of 3.0 - 3.2 volts at a bare minimum and ideally around 3.5 volts.

Tom


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## alexandrul (Feb 16, 2013)

*Re: 18650 maintenance questions*

Thank you for the information, Tom. I wasn't aware of the "under load" condition for the 2.8V reference.

However, the cells that were stored for months at 1.9V and 2.1V should be discarded, or are they still usable, that is the question.


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## VidPro (Feb 16, 2013)

*Re: 18650 maintenance questions*



alexandrul said:


> Thank you for the information, Tom. I wasn't aware of the "under load" condition for the 2.8V reference.
> However, the cells that were stored for months at 1.9V and 2.1V should be discarded, or are they still usable, that is the question.


Silverfox already indicated there is nothing Grey  about a cell that is sitting at 2.8v after the load is removed. Meaning they *all* sound like a waste of time to deal with.
They could "work" but if they are bad, they could cause problems when charging or using at high discharge rates. So at the least you should not trust them at all. I have slowly re-charged cells that were low, and it is quite a waste of time to deal with them. Experimenting is fun though if you can do it all Safely, and have nothing to lose.

If your sorting out the good and the bad out of a Pack, the low ones are usually bad, the high ones are usually "ok" . By high i mean ones that are still showing a 3.5+V . Only bad cells or a parasitic drain occuring would sit lower than that. Even after many months.

Only a seires of testing will determine if they are somewhat usable and slightly safe and not poor. During that time they should be treated as totally suspect.
safely charge them, some way that a full out thermal overload would not be a problem.
Check them for self-discharging over time, this usually only takes a few days to find ones that are internally degraded.
then discharge them and check for the total holding capacity.

at the least there are better "discarded" pack cells out there than these, read more Laptop battery dissasemble threads, and check things on the web, they often will list the voltages they get. If there are good cells in a dead pack it is more often when ONE (per series set) cell item fails, and the rest are usable. If the pack is instead full of a bunch of Iffy cell items, it probably isnt a good candidate for cells at all.

should they be recycled or tossed? probably all of them.


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## SilverFox (Feb 17, 2013)

*Re: 18650 maintenance questions*

Hello Alexandrul,

As VidPro mentioned it looks like they are all crap.

However, if you want to play and don't mind the dangers involved...

You can start a charge at a very low current and see if they will come up a little. Use something like 100 mV for about 15 minutes. Let them sit overnight and measure the voltage again.

At this point the cell may be up to a decent voltage. The next step involves charging the cell. You must make sure that you fully attend to this charge because there is a possibility that things could go south on you. Check the cell every 15 minutes to make sure it stays cool to the touch and terminate the charge if the cell gets hot.

If you manage to get a full charge on the cell, remove it from the charger and let it sit overnight. The next day measure the voltage again. If it is over 4.0 volts you may have some life left in the cell, but be cautious while charging.

The final step is to do a controlled discharge and make note of the voltage under load during the discharge. At lower loads you expect the voltage to be in the 3.6 - 3.7 volts range at the midpoint of the discharge. 

If all this works out, you have recovered the cell.

Tom


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## alexandrul (Feb 17, 2013)

*Re: 18650 maintenance questions*



VidPro said:


> Silverfox already indicated there is nothing Grey  about a cell that is sitting at 2.8v after the load is removed. Meaning they *all* sound like a waste of time to deal with.
> They could "work" but if they are bad, they could cause problems when charging or using at high discharge rates. So at the least you should not trust them at all. I have slowly re-charged cells that were low, and it is quite a waste of time to deal with them. Experimenting is fun though if you can do it all Safely, and have nothing to lose.



I saw that Xtar WP2 II can charge cells below 2V, but I had no idea how dangerous such cells can be, so I had to ask 
Thank you for your patience, I was 100% noob on this subject until last week.



> Below 2 volt the charger charges with about 0.5 mA, this is enough to reset a protection pcb (Note: The led is green).
> Between 2 volt and 3 volt the charger charges with about 80 mA.
> Between 3 and 4.15 volt the charger is applying regular charge current (See curve below).





SilverFox said:


> As VidPro mentioned it looks like they are all crap.
> 
> However, if you want to play and don't mind the dangers involved...
> 
> ...



Thank you very much for the very clear instructions, I will give it a shot with an Xtar WP2 II, under constant supervision. While it might be a waste of time in the end, it will be educative (and it's better to experiment with these recovered cells than with more expensive ones).


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