Help! My 18650 lost it's charge!

[Ogg Vorbis]

Hi everyone...

I went to turn on my Ultrafire Alpha C1 i got from DX which uses Ultrafire protected 18650's and it didn't turn on. I thought that it was rather weird cause it was fully charged up and was working only a couple of days ago. So I started tinkering and finally measured the voltage of the battery... it read 0.3V! I've no idea how this might have happened. I mean I would have noticed if it was turned on as it lives on my desk and has a pointed bezel so light would have been pouring out...

It's probably worth mentioning that I had to remove the plastic wrapper for it to fit in the flashlight, but I replaced it with a layer of scotch tape/sticky tape (I think that's what you guys call it!). I did however manage to short it out before i put this coating on so i'm thinking that could be the cause... only it happened a few weeks ago and was fine for all the time after that.

Can anyone shed some light on why this happened for me? Oh and I have read the safety threads on li-ion batteries...

Thanks,

Danny

 

[VidPro]

if it was "protected" then the curcuit should keep the CELL ITSELF from going below about 2.4v , which it usually recovers from to higher after you stop draining it.

the protected cells have thier own caveat, which you have discovered just when you peeled the insulation. there is a wire (flat piece of metal) that MUST run to the protection curcuit from the opposite pole of the battery. this creates a slight possibility of a dead short of the cell itself.
wether the protection is on the bottom or the top, this opposite pole connection has to get to the protection curcuit, and that means it gets close to the other pole. i assume you have seen this wire, and the insulation under it.

this wire depending on which pole it comes from, could also potentially connect to the body of the flashlight, and cause a short, or a discharge of the cell, if your tape insulation broke through somewhere.

once any of that stuff shorts, the protection curcuit itself can fail permenently, or the cell could dead short (and that wire gets red hot) or the cell could just get discharged completly , making it trash. OR, it could have just discharged to the protection low, and the protection disconnects the battery.

umm now what?
ok first if the protection kicks in, in certian cases , it can take putting it on the charger before it will reconnect. so if the battery is below 2.5v (for example) the curcuit will disconnect.
Putting it back on the charger will start it again.
BUT
if its shorted, then putting it on a charger would be a really bad idea. and if it discharged below "spec" it could be dangerous to charge it.
SO
umm, check all the connection, try and get a voltage reading on the cell itself minus the protection, see if there are any char points anywhere. see if everything is still connected correctally.
if your sure the cell is all connected right, and any short NOW doesnt exist, put it on the charger for a short time, and see what happens via the charger light, and re-check the voltage. if its shorted, dont leave it on the charger for time.

then i gotta say again, if the cell ITSELF went below the 2.4v it becomes a HIGH RISK for starting a fire during charge.

so EITHER the cell is discharged and ruined and unsafe, or the protection is broken, or a connection is broken, or the protection is just engaged., and/or a short might exist.
lotta help that was, i might as well have said, It Could Be Anything. Pictures help.

 

[Ogg Vorbis]

i might as well have said, It Could Be Anything. Pictures help.

But you didn't!
:bow::bow::bow:

I have just taken a reading from the side of the cell (-ve) and the +ve end and it reads 3.9V so you were right sounds like the protection has gone crazy

So should i stick it in the charger? everything looks to be ok? There is however a recess near the top and there's a couple of brown spots. Could these be burns or corrosion?

 

[VidPro]

I have just taken a reading from the side of the cell (-ve) and the +ve end and it reads 3.9V so you were right sounds like the protection has gone crazy

So should i stick it in the charger? everything looks to be ok? There is however a recess near the top and there's a couple of brown spots. Could these be burns or corrosion?

ok, so the cell is not low at all. so that helps reduce the posssibilities, now i would say chances are very good that the protection is ruined.

if you have a power supply, it would be better than a charger, just because i dont know how your particular charger would react if there was some problem. I would put it on the charger, but i dont know if i can tell YOU to put it on the charger i dont wanna mess anything up.

brown spots, browned components on the protection board, or charred components that turn to carbon dust when you slide a fingernail across them, would indicate that the protection curcuit might have been shorted, and is certannly toast.

Protection curcuits are $1.59 so you could fix it, but what Caused the original problem would be more important to me , than what it takes to fix it.

 

[VidPro]

oh i got it, there is some sort of insulator under the protection board. Can you tell if that insulator, has been breached, has a hole in it or charring there?
the insulator which is sometimes plastic and usually paper, and shoulda been that special thin electronics cardboard, is sometimes barley enough to insulate, and IF something connected through that, you could proably see.

 

[Ogg Vorbis]

I've just removed my make shift insulation and then i pulled the what looks to be a cardboard insulator away from the cell and pushed it back down. I took a reading from the protection circuit and the +ve end and success! 3.9V!

As for the brown stuff... i scraped it off with a screwdriver and it looks like some kind of corrosion. I dont think it's anything serious.

So how do i prevent all this from happening again?

 

[VidPro]

I've just removed my make shift insulation and then i pulled the what looks to be a cardboard insulator away from the cell and pushed it back down. I took a reading from the protection circuit and the +ve end and success! 3.9V!

As for the brown stuff... i scraped it off with a screwdriver and it looks like some kind of corrosion. I dont think it's anything serious.

So how do i prevent all this from happening again?

OK well i assume from that , some insulation is not insulating, prevent it by putting better insulation in., make sure the insulation under the board stays in place (because the original wrap is off the cell)

 

[scott.cr]

I've gotten quite a number of defective 18650s that "self discharge" down to unreasonable levels and end up being useless right out of the gate.

So far the best luck has been with LG brand 18650s... no defects yet. All the other brands have had high numbers of faults, and not just the 18650 sizes... all sizes have high rates of defects.

 

[VidPro]

duhh, there is one i missed.
to check for the short, VRSES a disconnection, you would use the DMM on continuity or OHMS, and see if the 0Volt reading you got, was also a Infinity Ohms reading, or a ~0 Ohms reading.
if it read ~0 Ohms then it would be shorted, if it reads infinity (usually flashing) then its a disconnection.

but dont try and read ohms or continuity if there IS power on what your testing.

 

[robm]

I think all you did was trip the protection circuit. I have the same cells and once it 'trips' the output appears to be approx 0v.

When the first occurred I thought the circuit had failed, but once in the charger it started to charge and then reported over 3.8v - I think the act of charging resets the circuit.

 

[Fallingwater]

I think all you did was trip the protection circuit. I have the same cells and once it 'trips' the output appears to be approx 0v.

When the first occurred I thought the circuit had failed, but once in the charger it started to charge and then reported over 3.8v - I think the act of charging resets the circuit.

That is true.
I once mistakenly shorted a protected RCR123. After a brief moment of panic I measured its output and it tested open. I thought I had killed the cell, but after putting it in the charger for a few seconds the circuit reset itself and the cell was alive again.

 

[Ogg Vorbis]

Just when i thought i had fixed it, had it reading 3.9V i put it back in the light and clicked it on... except it didn't turn on! So i took it back out and it read ~0V. I had a tinker with it again and once again it read 3.9V. So i put it in, turned it on, and nothing.

So i decided to stick it in my charger. I left it there for 5 mins and tried it again. Success! It lit up!

So what i'm thinking now is that perhaps the protectioon circuit kicked it cause the voltage was getting too low (even though it had a good charge previously). It also leads me to think that the protection circuit was kicking in at around 3.9V?

So problem solved... for now at least...

Thanks VidPro for all your support!

 

[VidPro]

still sounds like either the protection keeps retriggering off, which shouldnt happen once the "short" is removed, it just depends on what style of protection is used.
take the example of protected li-ion used in incadescents, when they need to hit the switch many times to get it to work, because the cold filiment draws to much current. it doesnt have to be put back on the charger then.

or something is still connecting that isnt supposed to.
or something is disconnecting, like one of them tiny hair legs on the chips in it.

really the only time the protection should stay completly disconnected is if the charge is low on the battery, hmm, and the charge could LOOK low if the cell was disconnecting from the protection curcuit . and the low on most of that stuff is set at ~2.4-2.5

nevermind, i am going to go back to my nancy drew mystery

 

[Bullzeyebill]

Discard the 18650. Life is too short to be working with a questionable LiIon battery. That brown stuff you scraped off is another reason to dump the battery (safely).

Bill

 

[sysadmn]

Discard the 18650. Life is too short to be working with a questionable LiIon battery. That brown stuff you scraped off is another reason to dump the battery (safely).

Bill

That'd be my vote also. Protected 18650's run $10 / pair - not having a flashlight blow up in my pocket is worth waaaay more than that to me.

 

[Fallingwater]

Perhaps the protection circuitry is defective and is draining your cell.

I agree with the guys up here ^^^ who say to discard the cell.

However, just in case you decide you want to try restoring it anyway, you could maybe cut off the protection circuitry and see if the cell works fine as an unregulated one.

 

[DM51]

I would most definitely NOT encourage the OP to experiment with this cell by cutting off the protection circuitry.

This is the sort of thing that happens with inferior cells, and is a perfect example of a false economy. Luckily, it has not vented and no damage has been done, except to the OP's wallet in wasting his $$ on bad cells.

You will save money in the long run if you buy all your Li-Ion cells from AW.

 

[Fallingwater]

Eh. I would.
Outside, with a bucket of sand nearby and wearing fire-resistant gloves, but I'm too curious not to do something like that.

Ogg Vorbis: you know, DM51 is probably right. Do what I suggested only if you're very curious and you know how to handle a lithium fire, otherwise (or even if you have mild doubts) trash the cell.