Finally had a Li-Ion battery failure

[fyrstormer]

I opened my Jetbeam TC-R1 tonight to discover...that I couldn't open it. It was sealed shut, like someone had twisted the two halves together with all their strength. I ended up having to use two strap-wrenches to get it open, and when I did, I found the head of the battery and the inside of the battery chamber were both discolored, and there was some corrosion on the brass contacts inside the head. The red plastic around the head of the battery had been bleached almost white by whatever had gone on inside the light while it was sitting quietly on the shelf, and there was reddish-brown buildup inside the battery tube that took a half-hour of scraping to remove.

The fact that I was using an AW IMR 18350 battery, which uses a lithium-manganese chemistry that doesn't contain free oxygen, is a little disappointing, but the TC-R1 is a soft-off light, and it has a titanium shell so loosening the head doesn't break the circuit. So I suppose something like this was bound to happen eventually. It sure would be nice if AW would make a protected 18350 battery; I much prefer to use Li-Ion batteries that have built-in low-voltage cutoff circuits.

 

[cyclesport]

The fact that I was using an AW IMR 18350 battery, which uses a lithium-manganese chemistry that doesn't contain free oxygen, is a little disappointing....

So I suppose something like this was bound to happen eventually. It sure would be nice if AW would make a protected 18350 battery; I much prefer to use Li-Ion batteries that have built-in low-voltage cutoff circuits.

I think this is the first time I've heard of this phenomenon. I too use several AW 18350 IMR's in several control ring lights mostly for their current dump capabilities, but never liked having to always be careful about swapping cells early since there are no protection circuits to avoid ruining them.

Perhaps you discharged the offending cell too deeply on it's last use cycle? Glad your light still works!

 

[reppans]

How long was the light sitting unused? Do you know what the parasitic current drain was? (If it still works, can you test it?)

I had an AW17670 fail - protection circuit failed when I dropped it a light from 3ft.

 

[fyrstormer]

Yes, the light still works. It took a while to clean all the gunk out of the inside, but nothing seems to have been damaged, only discolored.

The parasitic drain is so low I can't get a reading even on the <2mA setting on my multimeter. I can get a voltage reading, but no amperage reading.

The light sat for a long time. I don't use that one much. I guess I should've known better than to leave a battery in it, but all my other lights are either hard-off and/or use protected cells, so it's never been an issue before. I suppose I should switch back to an RCR123 in that light, and stuff a plastic shim into the battery tube to take up the extra space.

All of my Li-Ion flashlight batteries are getting old, some as much as 6 years old now, but I don't think the battery that failed was more than 3 years old. Not sure though. I didn't start labeling my Li-Ion batteries until I got into RC and I started dealing with extra-volatile LiPo batteries.

 

[recDNA]

So this must have been a cold vent?

 

[fyrstormer]

I have no way of knowing. I assume there must have been some heat involved, because the plastic around the positive terminal is discolored and warped. But not enough heat to burn through any of the flashlight components, anyway. I'm pretty sure the plastic insulator between the positive and negative contacts on the head of the light is made of nylon, and nylon is pretty heat-resistant.

 

[fyrstormer]

Just to follow up on this: No, it wasn't a cold vent. I happened to look closely at the shelf the light was sitting on and there's a ring of discoloration where the titanium bezel touched the shelf. It must have been caused by heat, because if it had been caused by outgassing leaking past the bezel seal, the aluminum-plated reflector would've been ruined and the glass would've been fogged.

 

[ChrisGarrett]

Just to follow up on this: No, it wasn't a cold vent. I happened to look closely at the shelf the light was sitting on and there's a ring of discoloration where the titanium bezel touched the shelf. It must have been caused by heat, because if it had been caused by outgassing leaking past the bezel seal, the aluminum-plated reflector would've been ruined and the glass would've been fogged.

Are you sure that it was a genuine AW 18350?

There are tons of fakes out there.

Chris

 

[nfetterly]

I just recently had a Panasonic sell stop working. Worked well in my SWM C22Cvn, turned it off, tried to turn it back on two minutes later & no go. Nothing across the cell - wouldn't charge. Hadn't been run down.

 

[fyrstormer]

Are you sure that it was a genuine AW 18350?

There are tons of fakes out there.

Chris

I bought it from LightHound.

 

[ChrisGarrett]

I bought it from LightHound.

I bought my first two AW IMR 16340s from him and they've seemed to be legit cells 3.5yrs later, lasting pretty long.

There are a lot of fakes being sold, but I think that LH was an authorized AW dealer.

These are all man made devices and some fail right off the assembly line and some fail prematurely.

Nobody's perfect.

I'd be more worried about the generic Chinese stuff coming out and not the properly culled Chinese stuff that AW uses in his smaller cells.

Move on and chalk it up to experience.

Chris

 

[fyrstormer]

I wasn't complaining in the first place. I was just sharing my experience.