Using Li-ion cells in LED flashlights safely

gmf2010

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I'm sorry if I missed this somewhere, but what is the best way to store Li-Ons that aren't being used?

I just purchased 2 AW14500s, a WF-139 charger, and a Nitecore NDI R2 for EDC.

I intend to keep one cell in the light and the other charged, at home, for a spare.

What is the best way to store the charged spare?

Also, if this isn't straying from the topic too much, I also have a box of CR123 batteries sitting in my desk drawer. Should I be storing these someplace else, like my refrigerator?

Thanks so much.
 

garden

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Mate, I think you've got yourself a bit too hypo about battery safety. I will admit I am not an expert on chemistry or batteries but the possibility of a li - ion battery exploding or firing up is probably the same as winning the lottery. For the battery to explode, it needs to reach some extreme temperature. The autoignition ( set on fire by heat alone, no fire no spark) for li -ion is probably somewhere around 500 degrees C. For 3.7 volts to do that in a short circuit, the short circuted battery needs to somehow destroy the ac dc adaptor and a 240 v current would be needed to create a fire. However the chance of this happening is low and most houses have a main switchboard that would switch off the mains electricity upon short circuit.



So overall I'm saying that the chances of fire from overcharging is very unlikely
 

SilverFox

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Hello Garden,

Welcome to CPF.

The reason for the emphasis on safety comes from the way we are using these cells. In a laptop or phone, we take great care not to drop or damage them. With a flashlight, it is easy to drop a cell, or the whole light, or sometimes you run the cell into an over discharged condition.

Most of us are not in the proximity of extreme heat, but if a cell suffers internal damage it can short out internally. Also, over discharging causes metal lithium to plate out within the cell. This metal is extremely unstable.

Now we have a situation where the next charge could cause a local problem where temperatures could get out of control resulting in rapid venting with flame. Since this initiates on a micro level within the cell, the household circuit breakers offer no protection at all.

The potential energy of this chemistry is high, so it is prudent to ramp up the safety measures when using or charging these cells.

Tom
 

Magic Matt

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I don't mean to be rude here, but surely there must be some massive errors in that information. If the chargers and batteries were anything like as dangerous as they are being made to sound, then they wouldn't even be allowed to go on sale in the UK. As it happens, I sit here with a laptop that has a battery with a whole bank of cells which take a hammering in terms of charging in the laptop and physical journeys in backpacks and bags. The warning make it sound as if I'm holding a stick of lit dynamite.

With my laptop, charging its bank of Li-ion cells, it is frequently left on charge overnight on the desk and I know of hundreds of people that leave their laptops on charge from a Friday afternoon until a Monday morning.

Most people charge their mobile phones overnight and don't worry about them blowing up. We carry them in our pocket the same way we would do a wallet, and you could argue a mobile phone is far more likely to short out internally from being in a wet coat than a torch would.

If you buy cheap cells from a country that doesn't have the same rules and regulations as far as safety standards go, then you need to take extra precautions... of course that goes for a lot more than just Li-ion cells. Any cells on sale in the UK have to confirm to fairly strict safety standards by law and it's illegal for a UK retailer to sell any that don't - as far as I know the US is the same, but feel free to correct me if I'm wrong. I believe the current standards insist on a fairly high degree of impact resistance as well as protection from over charging and over discharging.

If you bought a good charger conforming to the safety standards required, and cells to match, there's no reason you should be worried using them in off-the-shelf products that are designed to take them.

If you're going to start messing around putting components together that aren't designed to be used that way, then you need to take every precaution possible.

If we're talking about making our own circuits and modding torches, then yes we should take a lot of extra precautions, test everything, test it again, and then just to be safe, test it some more.
 

tsmith35

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The only real danger when comparing loose cells vs. battery packs really boils down to a few things:

Loose cells have a relatively large amount of terminal surface area exposed, increasing the possibility of accidental contact/shorting.
Battery packs have a relatively small amount of terminal surface area exposed, and generally have some form of electronic protection between the terminal surfaces and the actual battery terminals.

Loose cells generally have no protective container on them.
Battery packs generally provide a protective container to help protect the internal cells.

Loose cells are easily handled badly. They roll off tables, get dropped in trash cans, get dropped into boxes.
Battery packs are generally handled as well as the object that it is powering: laptops, cell phones, cameras, etc. They're treated better.

Loose cells generally have no protection circuitry.
Battery packs are generally protected by electronic circuitry designed to prevent overheating, overcharging, under-voltage use, and shorting.

Loose cells may be called upon to provide high amperage levels.
Battery packs generally provide lower amperage levels and have regulation circuitry to prevent excessive current flow above a specified level.

Loose cells may be dropped into any halfway compatible charger in any orientation.
Battery packs must generally be plugged into a specific charger that provides a physically keyed charge polarity, current level, and voltage. Actual charging is regulated electronically by a device-specific circuit.

Exploding batteries are not normal. They're not an everyday occurrence. It likely won't happen to you. But ignoring the possibility of injury due to an exploding battery is foolish. Do you drive with a seatbelt on? Do you have a smoke alarm in your house? Have all family members been taught to dial 9-1-1 in an emergency? The possibility that your life will be saved by a seatbelt, that you'll ever need your smoke alarm, or that you'll ever have to dial 9-1-1 are all extremely remote. But it's generally thought that it's better to be safe than sorry.

Learn what lithium batteries are capable of. Learn how to handle them safely and what to do in case of a fire or explosion. And hope you never need to deal with it. Sure, you can stick your head in the sand and say, "It'll never happen to me". There's a good chance you'll be right.
 
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SilverFox

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Hello Magic Matt,

I am not sure how things are in the UK, but in the US you can't run down to the local store and buy a Li-Ion loose cell, and a charger to charge it.

The reason the local stores don't sell loose cells is because Li-Ion battery manufacturers won't sell them to them. Battery manufactures are even hesitant to send out samples for evaluation, unless you provide them with details on the battery pack construction and the safety measures you have in place to protect the cells from over charge, under charge, and physical damage.

Cell phones and laptops are engineered, designed, and have safeties to protect the battery pack. Loose cells in a flashlight are many steps below this, and thus the main battery manufacturers don't sell loose cells.

Even with all the safeties in place, you will recall that a few laptop battery packs ended up rapidly venting with flame.

Here is something you can do to verify all of this. Contact Sony, or Sanyo, or GP, or Panasonic, or LG, and tell them that you are interested in purchasing some loose cells for your flashlight, and see what kind of response you get...

The proper way to charge a Li-Ion cell is to use a CC/CV algorithm with the voltage limited to 4.20 volts (+ or - 0.05 volts) and have the current shut off when it drops below about 50 mA. If the cell voltage is below 3.0 volts, the charger should start off with a very low charge rate until the cell reaches a voltage of around 3.4 volts, then it can continue on with the CC phase. Another safety built into the charger is a timer. If the charge has not completed in the alloted time, the charge is terminated. There are a few other safety checks done to make sure the cell is OK to charge as well.

How many chargers available to the CPF community follow this charge method? Your cell phone does, as does your laptop. The Pila IBC charger comes close, but even it doesn't have all the safeties required for "safe" charging.

12 volt automobile batteries are generally considered safe as long as you take the proper precautions when handling them. However, if you have ever witnessed one explode, you would think twice about their safety. Fortunately this does not happen very often. I have witnessed this, and it was very sobering. I have also witnessed some 18650 cells rapidly vent with flame, and have a great respect for the energy contained within the cell.

The reason the battery manufactures don't sell individual cells for the local shops to pass on to you is because of these safety concerns, and liability. We understand these concerns and take them very seriously. We have taken the stance that education is the best way toward safety and try to explain the safe use of Li-Ion cells.

When you use a piece of equipment that is well designed and has all the safeties built into its operation, you can plug it in and forget it. When you don't have this, you have to take safety into your own hands and act accordingly.

Tom
 

Magic Matt

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I agree with most of your points, tsmith, but these I disagree in part with...

Loose cells generally have no protective container on them.
Battery packs generally provide a protective container to help protect the internal cells.

The only cells I've seen have some sort of protection on them - usually a plastic vacuum wrap or similar, which is surprisingly resilient to scratching and moisture. No way near as touch as a solid casing, but I wouldn't class it as no protection at all.

Loose cells are easily handled badly. They roll off tables, get dropped in trash cans, get dropped into boxes.
Battery packs are generally handled as well as the object that it is powering: laptops, cell phones, cameras, etc. They're treated better.

I totally disagree there. Having seen many battery packs abused to the point where they're scratched, scuffed, batterred etc. I would say most of my cells are handled better than my battery packs! I've certainly dropped my battery packs onto a concrete floor trying to change them in near blackness before, and not thought much of it (except to check for cracks).

Loose cells generally have no protection circuitry.
Battery packs are generally protected by electronic circuitry designed to prevent overheating, overcharging, under-voltage use, and shorting.

I may be wrong, but I thought all Li-ion rechargable packs or cells had to have the circuitry before they were allowed to be sold in the UK. This may in part be why they're so hard to find.

Loose cells may be dropped into any halfway compatible charger in any orientation.
Battery packs must generally be plugged into a specific charger that provides a physically keyed charge polarity, current level, and voltage. Actual charging is regulated electronically by a device-specific circuit.

A charger that has no reverse polarity protection, even on something as basic as a NiCd cell, shouldn't be used anyway IMHO. As far as I know, cells are usually keyed, and a good charger also takes avantage of that (I can't physically put my AA cells in the wrong way into my charger for example - they wont touch the contacts if I do).
 

Magic Matt

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Hello Magic Matt,

I am not sure how things are in the UK, but in the US you can't run down to the local store and buy a Li-Ion loose cell, and a charger to charge it.

I was going to post this... then looked again in shock as I realised it's not an RCR123, it's a CR123 and charger!!
http://uk.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=5109376

(I should add I usually run screaming from anything branded Uniross - I'm not even convinced their NiMH chargers work that well).

You have to hunt around to find Li-ion chargers, but you can get them. I've not seen anything that takes or charges 18560 cells, only ever (R)CR123. I wish I had picked up the Panasonic RCR123 cells and charger when I saw them, but I wasn't as educated then as I am now - I've never seen it again since and had people tell me it doesn't exist - it could have been a CR123 charger I guess, but it was definately Panasonic and came with two cells.

If the cell voltage is below 3.0 volts, the charger should start off with a very low charge rate until the cell reaches a voltage of around 3.4 volts, then it can continue on with the CC phase.

That surprises me - I didn't think you were supposed to charge them at all below 3.2V!

What we really need I guess, are universal Li-ion battery packs and chargers as opposed to loose cells.
 

Magic Matt

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"RCR123" is a conventional designation, but by no means standard. "CR123 rechargeable" means exactly the same thing.

Ahhh, thanks for clearing that up. :)

Still, an off-the-shelf rechargable CR-123 with charger ... and they also sell spare cells ... part of me is curious to know how it stacks up against other chargers recommended on here. If RS sell it, then that means a high street retailer could stock it if there were a demand.
 

45/70

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Removed original content of this post.

Due to the distraction caused by "holiday cheer" (at least that's the excuse I'm giving :)), I somehow:thinking: thought I was responding to another thread about RadioShaft RCR123 chargers.

Dave
 
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rmteo

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I'm wondering, since Matt is from the UK, if he was referring to RS Components - a British distributor of electronic components and the like, kinda like an equivalent to our Mouser, Digikey, etc.
 

45/70

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I'm wondering, since Matt is from the UK, if he was referring to RS Components - a British distributor of electronic components and the like, kinda like an equivalent to our Mouser, Digikey, etc.

Ah, after looking at Matt's link, I find you are correct rmteo. My apologies yet again! :candle:

And to be totally politically incorrect (I live in the U.S.)

Merry Christmas All! :santa:

Dave
 
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LeifUK

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There is a post on this site from someone who placed normal Lithium batteries in a charger and one exploded and vented toxic fumes.

Anyway, I am surprised at the apparent danger of these Li-ion cells. The laptop batteries that caught fire were faulty, very few caught fire (relative to the number sold), and all affected units were recalled.

Rechargeable Li-ion cells are used in cameras, many millions of which are sold each year, and in iPods and other devices. These are dropped routinely, and used by juveniles. I am unaware of any incidents from kosher units. (I have read posts from several photographers who bought cheap third party camera batteries and experienced fires. In one case the battery caught fire duing charging and the owner's house was partially burnt down.)

According to the original post torch/flashlight cells are very dangerous. Surely no normal person would watch a charging cell, and check it every 15 minutes. It's madness. According to this thread torch/flashlight cells are unstable due to poorer safety measures. Why is that? Why not force them to adopt the same standards. It all seems weird. Sorry for my tone, but it does not make sense.

The reason why they are so hard to obtain in the US is probably due to the litigeousnous of the country. After all you people can sue a company because they sell a cherry tart without a warning that it is hot. (I like to think that our judges would class the customer as a moron, and dismiss the case. I fear I am wrong. When you cough, we catch a cold.)
 

tsmith35

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The only cells I've seen have some sort of protection on them - usually a plastic vacuum wrap or similar, which is surprisingly resilient to scratching and moisture. No way near as touch as a solid casing, but I wouldn't class it as no protection at all.

The shrink wrap doesn't provide much protection against physical damage, i.e., distortion of the cell case, like a battery pack's physical case would. It will protect against minor damage, but that's about it.

I totally disagree there. Having seen many battery packs abused to the point where they're scratched, scuffed, batterred etc. I would say most of my cells are handled better than my battery packs! I've certainly dropped my battery packs onto a concrete floor trying to change them in near blackness before, and not thought much of it (except to check for cracks).

But that's just it: the plastic case helps protect the cells from physical damage, whereas a bare cell may have a corner dented, end impacted, etc. If the impact doesn't crack/break the plastic case (and physically damage the cells), the cells are likely okay.

I may be wrong, but I thought all Li-ion rechargable packs or cells had to have the circuitry before they were allowed to be sold in the UK. This may in part be why they're so hard to find.

Packs, maybe. But individual cells probably don't have any protection unless specified.

A charger that has no reverse polarity protection, even on something as basic as a NiCd cell, shouldn't be used anyway IMHO. As far as I know, cells are usually keyed, and a good charger also takes avantage of that (I can't physically put my AA cells in the wrong way into my charger for example - they wont touch the contacts if I do).

A charger without reverse polarity protection shouldn't be used, but they are certainly available. Poke-yoke dictates that a charger shouldn't accept a cell backwards, but I own several chargers that will happily accept backwards cells. Bad design. Since I know the dangers of inserting cells backwards, I'm very attentive when I put batteries in my chargers. I'm sure the possibility of fire/explosion would be much greater if I didn't pay close attention.

Knowledgeable folks such as yourself and most others on the forums won't ever have problems with their lithium batteries. But most folks in the general public simply don't know any better, so it's worthwhile for all of us to caution friends and family as to how they should treat lithium rechargeables.

I know I have kept lithium batteries on-charge for years (literally) until I found out how dangerous that practice is. Now I plan ahead and charge my lithium cells/packs as needed to maintain a long cell life and provide a safer environment for me and my family. There's the possibility that I could have continued the practice of leaving lithiums plugged in for the rest of my life and suffered no ill consequences. But why chance it?
 

JBorneu

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Hi all

I'm very busy at the moment, so I haven't been able to check CPF for a while. Looks like there has emerged a whole new discussion within this thread.

The thing is, folks, Li-ion cells can be very dangerous. That is an irrefutable fact. If you think li-ion cells cannot pose any danger, you don't know what you're talking about. It's that simple.

The key word here is "can". When lithium cells are treated the way they are supposed to be treated, they are not dangerous. That is why there are millions of consumer electronics which run on li-ion cells used daily without any accidents. The manufacturer designs a device and designs a battery pack to go with it. As long as the proper pattery pack is used in the proper device, the manufacturer controls every single step: the power source, the charging algorithm, the maximum charging voltage and current, the maximum discharge current, the overdischarge protection, the quality of the components, the various safety measures, the capacity and quality of the cells, the packaging ... Basically, he can make sure himself that every single component is a perfect match for the cells and the rest of the device, be it an MP3 player or a laptop. That is why he will sell you a li-ion battery pack for your laptop: because he knows he did everything right himself and nothing will go wrong as long as you don't tear the battery pack open and start playing with the individual cells and putting them in different chargers and making a charger out of a mobile phone / laptop / power supply / circuit of resistors (like a lot of people do here on CPF). Those are all things which can be done without accidents, but they all require a level of knowledge far above that of the regular consumer.

Now, when you start playing with loose cells, the manufacturer has no control whatsoever about the way the cells are used. He does not want the responsibility of selling loose li-ion cells to regular people who don't know what they are or how to use them, so he won't sell them at all. Remember, whe are putting loose cells in flashlights, often in series, often without protection circuitry, often draining the cells near or over their maximum rated current. This is "edgeplay", as you could call it: we are pushing the boundaries of safe behaviour. Having to carry responsibility for that is the nightmare of every battery manufacturer. That is the reason he only sells battery packs and not loose cells. People are stupid and careless, and he knows carelessness will cause serious accidents with li-ion cells. It WILL cause serious accidents. No "can" this time. Ignorance and carelessness go hand in hand (and expertism and carelessness sadly do too) and they don't mix with li-ion cells without catastrophical consequences.

My first post tells nothing but the truth. Li-ion cells are dangerous when used improperly but when you do what I write in the first post you will not have a problem. Remember people, the average IQ in the western civilization is 100. Everybody with any form of higher education (post high school) has at least 110-120. Most members of CPF have an IQ above 100. However, that means there is an equal number of people who have an IQ (sometimes far) below 100. Those people have an internet connection too, and most of them can read and use a credit card, which makes them capable of buying and mistreating li-ion cells. I sincerely hope my first post scares away everybody who is not intelligent enough to use li-ion cells in a safe manner. I think it does, and that is part of what it is intended to do. I'm not going to put a number on who is and who isn't intelligent enough because common sense is not measured in an IQ test so a 90 can have it while a 110 can lack it. When I consider all the kinds of people who can read this thread: child, elder, dumb, smart, male, female, factory worker, deskjob, tradesman, nanny ... I can tell myself honestly that any of these who follows my advice will not have an accident. Some people think they can be safe with less safety measures. If you think you can, feel free to do so, but it is entirely your own responsibility. I am not an expert, but I know for a fact that the advice in my first post is sound and will prevent accidents. And anybody who is heavily overwhelmed and scared away from li-ion cells by my first post shouldn't be using loose li-ion cells anyway.

I don't have the time right now to join the discussion about what is and what isn't safe with li-ion cells and packs etc, althoug it is a very valuable one, but now you know why I stand by my first post and will not lighten it.
 
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45/70

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Just to add a bit to what JBorneu said (I'm not too sure about the IQ thing, I think folks with a higher IQ are more likely to stretch the limits, myself), here are two posts that I recently made in another thread, that deal with why loose Li-Ion cells can be a higher safety risk.

Dave
 

LeifUK

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Quite frankly it sounds as if these things are not safe for sale to consumers, and I am surprised the companies can sell them to the general public. I'm not sure IQ comes into it. I know very clever people who are rather distracted, and would surely not last long with these cells. One aspect of clever people is the ability to pursue an idea and ignore distractions. Such as smoke from a nearby charger .... :eek:
 

DM51

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Quite frankly it sounds as if these things are not safe for sale to consumers, and I am surprised the companies can sell them to the general public. I'm not sure IQ comes into it. I know very clever people who are rather distracted, and would surely not last long with these cells. One aspect of clever people is the ability to pursue an idea and ignore distractions. Such as smoke from a nearby charger .... :eek:
LeifUK, please do some reading on the subject before making such lofty pronouncements.

Li-Ion cells are not sold to "the general public" in the way you suggest - you can't just walk off the street into a store and buy loose Li-Ion cells.

They are only on sale to those who specifically look for them. It is completely unnecessary for people to be subjected to alarmist posts such as yours, claiming that they are dangerous. They are quite safe as long as you understand them and observe basic safety precautions.
 
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