Harvested 18650s from laptop battery... now what?

[DrScum]

So, perhaps this discharge test should be done outside?

 

[SilverFox]

Hello DrScum,

That is not necessary. Most of the danger comes during charging.

Tom

 

[Poppy]

Hello DrScum,

That is not necessary. Most of the danger comes during charging.

Tom

I am also relatively new to all this, and have done a bunch of reading. I believe that you Silverfox have a lot more knowledge that you can share that would be beneficial to the lot of us. One sentence responses are helpful, but in many respects, are not much more than a tease.

I don't have a "dischargeable" charger. I bought a XTAR WP6II as recommeded by some on this forum. It will charge from AC or 12 volt DC from a car cigar lighter. I am not inclined to buy another charger that will also discharge, in retrospect, that might have been a better choice, maybe. I do however have a number of flashlights that will discharge batteries. So along with DrScum's line of thought... I have tested some batteries relative capacity buy putting them into the same flashlight and turning it on high then I checked the voltage of the battery each fifteen minutes or so, when it got too low, I stopped the test. I then logged THAT particular battery.[edit] That particular battery and how long it took for it to reach under 3.0 volts. I could then compare it to other batteries [end edit]


Tom,
Other than suggesting buying a hobby charger/discharger would you please make some other suggestions to the average Joe who may already have a charger? In addition, do you have a hobby charger/discharger that you would suggest to someone who is just starting this sport?

 

[DrScum]

Charging a bad cell is the most dangerous... but it would have to be charged to run a discharge test to determine if the cell is bad... but, it was in a laptop cell, albeit with protections for things going wrong, getting charged and discharged... presumably discharging at a much lower rate than a 10 bazillion lumen XMLMNOP light would.... so.... ??

Most of my battery knowledge is with NiCads in RC cars, though I do know a bit about Li-Ion cells and their dangers... i.e., hydrofluoric acid, venting, etc.

Perhaps some suggested reading material would explain the discharge test reasons a little better.

 

[tatasal]

I bought my chargers in this order: C9000 (because my first light was a TK41), then a Pila IBC (because of my XT11 and SC600). However, I got to know the fun (and most importantly the suspense) from harvesting laptop cells. For me, it's a lot more fun experimenting with laptop cells than buying brand-new ones, so I bought a hobby charger. (iCharger 106B+) It's all part of the learning (and spending) process in a flashaholic's life.

So it's up to the individual. If you think you are the type who has the interest and patience for such things (ie: hobby charger), it can be a second hobby. You can see 'life' in the cell itself as the digital display gives you real-time information, not just waiting for a red light turning into green.

 

[DrScum]

I'm nerdy, but not that nerdy... nor am I a flashaholic; more of a gearhead type. I'm not looking to grade, sort, match, etc. these cells... want to charge them and use them in a flashlight... and more than likely in a sub-400 lumen flashlight. I use my lights for EDC work, walking dogs, etc... not signaling aircraft.

 

[VidPro]

I am also relatively new to all this, and have done a bunch of reading. I believe that you Silverfox have a lot more knowledge that you can share that would be beneficial to the lot of us. One sentence responses are helpful, but in many respects, are not much more than a tease.

I don't have a "dischargeable" charger. I bought a XTAR WP6II as recommeded by some on this forum. It will charge from AC or 12 volt DC from a car cigar lighter. I am not inclined to buy another charger that will also discharge, in retrospect, that might have been a better choice, maybe. I do however have a number of flashlights that will discharge batteries. So along with DrScum's line of thought... I have tested some batteries relative capacity buy putting them into the same flashlight and turning it on high then I checked the voltage of the battery each fifteen minutes or so, when it got too low, I stopped the test. I then logged THAT particular battery.


Tom,
Other than suggesting buying a hobby charger/discharger would you please make some other suggestions to the average Joe who may already have a charger? In addition, do you have a hobby charger/discharger that you would suggest to someone who is just starting this sport?

Silverfox has written BOOKS on this stuff, I am not one to herass people with a "do a search" but at least check out the One stickey at the top http://www.candlepowerforums.com/vb...ronics-Batteries-Included-Threads-of-Interest

In this thread the item is UNPROTECTED, a cheap hobby charger will do a discharge test, even any hobby charger that can STOP at a voltage that would keep the battery within specs. Otherwise the other methods are a total pain in the butt. keeping the cell from discharging low by checking manually is almost impossible. Why? because when the cell is "depleated" it tanks fast, it does not put out much current and under load the voltage Drops fast. so at this tiny area of criticality the cell can get damaged.

In respect for the cell either protect it, buy protected cells, or a hobby charger (even cheap) is a very logical choice. I have all kinds of Stuff for working with batteries, and my stupid $39(type) china hobby charger is the best AND the cheapest way to do a discharge, when the cell is unprotected. for a few bucks the cell can be protected, and wrapped.

If you only have a charger:
With that said, and without a discharge testing to be SURE of what you have, testing the Self-Discharge of the cell is another possibility to see if the cell is in good shape or not. In Most situation (not all) a cell that is bad or going bad, will drop in voltage in a few days from its full charge state. Rest the cell after a charge, test the voltage, then test the voltage again in 2 days. the voltage should not change by more than .01 even.

Same basic thing, the charger should stop charging. on these cells that do not reach full charge, and discharge at the high end, it can be noticed when a charger will not stop putting power in, because the voltage did not get to the around 4.2v. if a light or a meter on the charger shows that the cell isnt finishing, it might be bad.

Li-ion cells have a high acceptance of the charge tossed at them, they should not get warm when charging properly let alone getting hot. In the usual chargers that were using at normal rates, Subtract the heat that the charger might have, and the cell should be cool. any unusual heating that occurs in the cell when charging can identify one that has internal shunting. it could have been damaged from low discharge, or just too old.



All the cells that are in all the consumer products are protected, even these Were protected originally by some sort of pack protection (if it worked right, without that protection, ya pretty much gotta know the specs, and need some sort of equiptment, anything else is a usefull Learning process

 

[DrScum]

It sounds like all you can do with these batteries is watch them charge and discharge with a hobby charger. They're getting a lengthwise wrap of electrical tape and going in the battery recycling bin at work.

 

[Poppy]

Charging a bad cell is the most dangerous... but it would have to be charged to run a discharge test to determine if the cell is bad... <snip> though I do know a bit about Li-Ion cells and their dangers... i.e., fluoric acid, venting, etc.

Perhaps some suggested reading material would explain the discharge test reasons a little better.

DrScum,
You may find the info in this sticky informative.

http://www.candlepowerforums.com/vb...6-123-Primary-Lithium-cell-info-testing-links

I don't recall the exact low voltage point, but if I understand the info correctly, the problem occurs while charging a Li-Ion when it has been discharged too low (below 2.4 volts or something like that) none of the cells that you listed above are that low.

Also it seems to me that a hobby charger that can also do a capacity test on a battery is helpful but not necessary. If a battery gets too low in voltage, dispose of it and don't charge it. Problem solved.

 

[VidPro]

There are many (now) led flashlights that will take a single 18650 that will stop operating, or purposfully cut-out at a low voltage. If you know the specs of a flashlight, or test it, or check out a review with a discharge graph, you can find lights that would not damage a li-ion , or as easily.

Not a light with a "boost curcuit" because it would need protected for sure. more often it is lights that had "buck" type curcuits, and use 2X123 lithium primary cells.

That is what people will use an unprotected in, and "get away with it" because it will not discharge the cell beyond specs.

 

[VidPro]

none of the cells that you listed above are that low.
.

That is what I thought too, there is good chance that DrScum has some usable cell items from the pack.

 

[Poppy]

Silverfox has written BOOKS on this stuff, I am not one to herass people with a "do a search" but at least check out the One stickey at the top http://www.candlepowerforums.com/vb...ronics-Batteries-Included-Threads-of-Interest

<snip>

VidPro,
Sorry If I crossed any lines.

Your thoughtful response contained more helpful info than many of the others in this thread. Thank you!

If a cell is BAD, wouldn't it drop off really quickly compared to other GOOD cells? If it drops off too quickly, there's no sense in trying to charge it, to use it, that just wouldn't make sense.

I don't want to argue, obviously the best thing is to have a hobby charger that will discharge too. IIRC the hobby chargers that I looked at were in the $80 range. I personally didn't want to spend that to check the capacity of batteries.

 

[VidPro]

VidPro,
Sorry If I crossed any lines.

Your thoughtful response contained more helpful info than many of the others in this thread. Thank you!

If a cell is BAD, wouldn't it drop off really quickly compared to other GOOD cells? If it drops off too quickly, there's no sense in trying to charge it, to use it, that just wouldn't make sense.

I don't want to argue, obviously the best thing is to have a hobby charger that will discharge too. IIRC the hobby chargers that I looked at were in the $80 range. I personally didn't want to spend that to check the capacity of batteries.

No lines crossed, i was just trying to indicate that silverfox sorta said it all :shrug:, eventually if you mess with this stuff you will end up with a voltmeter and a hobby charger, to get the fact of the cells.

Yes drops faster the worse it gets, usually would be dead (too low) in the pack to begin with. The sence in charging it would be to test those 3 parameters. So yea i do charge them to check that stuff , when it is unknown i just charge it in a way safer place.

Tenergy and accucell and other cheap chargers they are pumping out are very similar in operation, cheap and more functional and long lived than i would have thought. While a $100 one will still be better built and better long term choice, i am just glad that the cheap ones did the job. With some shopping you can probably get a usable one for about $30 but it would be the one that needs 12V power , power supply or battery.

 

[Poppy]

Yes drops faster the worse it gets, usually would be dead (too low) in the pack to begin with. The sence in charging it would be to test those 3 parameters. So yea i do charge them to check that stuff , when it is unknown i just charge it in a way safer place.
.

Emphasis mine.
Outdoors and away from the house would be a good idea. If a cell were to demonstrate its badness while charging, would it likely destroy the charger? I'm asking because I really do not know.

I guess one could use magnetic connections, and place the questionable cell away from the charger by a few inches.

 

[VidPro]

I have a bunch of ways to do safer. the garage cement used to be a good way, but then I realised there are a lot of flamables stored out there.
an old aluminum pan (tall) , or a kitchen size metal garbage can, making sure to not short anything on the metal. outside rarely, because of dew moistures, but that works during the day, in the shade.

The chances of anything happening are very very low, when they are shunted internally it takes quite a bit of current/power to get enough heat, most of the cheap chargers wont fire a cell unless there was lots of things going wrong.
IF anything did occur, it would be toxic gas releaces, explosive gas forming (like wood gas), fire comming out of the top like a rocket or fireworks. So a open container (no contained gas combustion) high enough that it cant fly out. simple cheap and should cover any incidentals.

i dont worry about the charger, the hobby charger has the wires, the cheap consumer charger is to cheap to care, when the chances of anything occuring is so low. I have "popped" some cells with gas, but they were good cells and the only popping was the anode disconnect thing working. the anode disconnect (built into cylindrical cells) disconnects the power when the pressure in the cell gets to high.

 

[Poppy]

OK... so I guess MY concern is this. I believe that my charger puts out 300 ma. Could that cause a bad battery to go on fire? I read about the poisonous gases, so I don't charge any in the house (although I do in the attached garage) . IF it could cause a fire, I want to be sure to put it far enough from combustables that there is no danger.

ANy ideas? I agree that the chances are very low or there would be hundreds of "news" reports of the dangers of batteries.

 

[VidPro]

it is just not likly at these low rates. Although when people say it is "impossible" I cant discount the idea of a very localised tiny area in the battery that ALL the power is going to one bad short in it, and some lithium plating. Some electronics in the charger/adapter going bad, sending AC into it or some such crasy possiblities.
For my normal charging, it IS in the house, when i am here. I have had a few fires from ni-mh and ni-cd , i was around, put it out and went on. i wouldnt be the first sciencegeek that messed up I have extinguishers.

 

[Poppy]

Sorry, I got side tracked. I don't want to destroy my charger with a questionable battery. If I question a battery, should I put it in a carrier, or somehow separate it from the charger while charging?

 

[VidPro]

Sorry, I got side tracked. I don't want to destroy my charger with a questionable battery. If I question a battery, should I put it in a carrier, or somehow separate it from the charger while charging?

I wouldn't , I didnt even with known bad ones i was testing for how much heating they will do. But I couldnt decide for you.

 

[Poppy]

Thanks VidPro, I don't recall reading any warnings or precautions, that came with the charger, regarding charging fully dead batteries, so I guess I will have to go with that.

Have a great day, and thanks for your time!