where's the kaboom?

Batteries and Chargers Rechargeable Batteries
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Okayokayokay, so I got my trusty EBL 14500 in my GTmicro. Last I checked it (days ago, not last month or anything), it blinked out 3.6V, which is low, but not in need of any immediate recharge.

Seems my cats, or at least one of ’em, doesn’t know the meaning of the word “boundaries”, and climbs onto my table, etc., and swings his tail around like a club. I swear, he must have ankylosaurus DNA somewhere in his genome.

Well, after picking up my lights off the floor and putting ’em back on the table for the umpteenth time, I notice that the ’micro’s sideswitch is dark. Odd, but sometimes that glitch kicks in and the sideswitch light stays dark. Nope, totally dead. Tailcap’s on tight, so it’s not locked out or anything. Odd.

So I unscrew the cap to check on the cell, and it’s sloooowly sliding out. Wtf?? It’s wet! And it stanks. And the wrap’s completely split open like it overheated! Again, wtf??

Yep, the beastie leaked out inside the light. Okay, so that goes right into the garbage. I wash out the tailcap spring and everything with detergent and water (no corrosion anywhere that I could see). Then after rolling paper towels into tubes and running them through the battery tube multiple times, I finally wash out the innards by drizzling detergent into the tube and running hot water down the pipe multiple times. Whole thing’s drying off now.

So, it had to have happened recently, whether the little furball accidentally turned it on and it ran down because of no LVP, or it just self-drained in a matter of days from 3.6V to leaking. I’m just amazed it didn’t go all supernova if it leaked and/or heated enough to split the wrap. And no “uncontained failure”, either? Small miracle, if you ax me.

Either way, I’m definitely reconsidering keeping any cell in a light if not in active rotation.

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That’s kinda what I was expecting when a Li cell would leak.

Figure conductive electrolyte shorting tip to case (reflector down, so it all pools by the driver), may’ve shorted the cell even more. Kinda like a half-puke making you gag from the taste’n’smell of the puke to make you full-on puke even more.

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I once used a 16340 light with a magnetic tail-cap while I was assembling a new gas oven, then left it inside during the oven’s first use. It was baked at 200℃ for around an hour. The cell leaked but there was no boom and the flashlight was fine.

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I’m interested to know what flashlight is that? :slight_smile:

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Are you sure your cat didn’t just piss on it and it shorted?

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I had a 16340 leak also without a kaboom. The light was never the same.

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The only battery I had that leaked was a Nitecore. When I brought it to their attention, they did not seem interested in the least.

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Here kitty kitty. Bad kitty.

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On first read i thought it had split the case, and i was gonna ask about what the innards looked like and how it was constructed, e.g. jelly roll around a mandrel or flat layers of a rectangular pack, etc.

but then i see that it was only the wrapper split, so the leakage was out the vent under the cap. Seems strange that it got so hot and over pressurized enough to vent during a total discharge. i wonder if there is a datasheet available for that cell to look at the chemistry.

The big Kaboom with fire usually occurs during a charging session after a deep over-discharge event, but sounds like you had a close-call and were lucky.

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This was a good post for me as it acted as a reminder to have some serious respect for Lithium Ion batteries. I was going to suggest the alkaline battery cleanup with vinegar, but of course LiIon batts don’t leak a strong base like alkaline leakers thus your soap/water cleanup makes sense.
I found a few good links re: LiIon battery hazards and cleanup. I had one go south as in take off like a smoky rocket across my workshop one when trying to extract a 18650 batt from a vape pen, batt shorted I guess, scary shit.

I think taking batts out of non-rotation lights is sensible. This thinking makes lights with non-removable batts less appealing to me now.

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Are most or all non-removable li-ion batteries protected cells? Might be a stupid question but I actually don’t know.

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They don’t really go boom. They can spit a little fire if the can gets penetrated in some way. One little tiny cell in a flashlight isn’t going to be able to spit much fire. I think being in the flashlight is probably the safest place to keep them unless it’s a light with multiple cells. I would retrieve that from the trash and take it outside and look for dents in either end. Does that light have springs in both ends? It’s probably related to the fall in some way but was it a battery issue or did the flashlight do something to cause a quick short high drain?

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Nope, it’s thoroughly waterproof, even from the inside. :laughing:

Seriously, battery tube from head was a chore to unscrew, so drizzled detergent down the hole and completely drownded it in hot water coming full blast from the faucet. Once I did unscrew it into 3 pieces, I was able to completely clean out everything.

No condensation under the glass, not a hint of fogging, nuttin’.

Dropped in a LFP cell (had it handy), and it still worked fine.

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I had a pair of ’123s go all China Syndrome in my MH20 for some reason. Both wraps were split and crinkled, both cells down to almost 0V, but no leakage. Nfi how that happened.

Still chugging along, thankfully.

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No, all li-ion are not protected, in fact none are from the factory to the best of my knowledge. The protection circuits are added post production and re-wrapped. All have intentional weak spots to reduce the violence of venting from the factory, so actual explosion is not what they do. normally. IMR, and INR chemistries are less volatile than the ICR that was used previously. Usually a battery venting might have fire but not an explosion. Inside a light there is less oxygen, so I am not surprised a tiny 14500 did not have flames. Had the same happened in a light containing 4x18650 cells it might be different. Had this been an ICR battery, it might have been the kaboom you speak of, but the stored energy of a 14500 is not going to be enough to be an extremely impressive kaboom. The fact that the cell vented without flames at all is fortunate even with IMR, and INR. You can easily see on the internet, videos of controlled intentional ventings by doing insane things like dead shorts or hitting them with hammers, with sometimes less than impressive results. That being said, even the INR and IMR can if venting cause flames. It can, if depleted too far, cause venting and flames if attempting to recharge. That is why most chargers, will refuse to recharge batteries that are too low in voltage. Some expensive re-chargers have special re-charge teqniques to recharge very depleted cells, but I would not risk it. I have had a house fire before, so I tend to take li-ion batteries and their potential dangers very serious, and do not push the envelope with their use. If a battery is too depleted to accept normal charging, I toss it. I do store some batteries in single cell devices with the tailcap loosened, but most I store in plastic boxes. None are stored long term in multicell devices. It is not that hard to remove them and put them in 2 cell plastic boxes for their storage. I have never seen or heard of a battery self depleting, and then venting due to low charge, and better li-ion batteries can hold their chages for years in storage…self depleting very slowly. Most violent venting events are due to the batteries mis-use or as in videos, intentional acts.

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A lotta people have lights all over the place with cells in ’em: in drawers, in the garage, in the basement, scattered all over the place like they’re old plastic D-cells-and-hotwire-bulb flashlights, and if you forget the check on ’em, or forget about them completely, that’s exactly what can happen to them. Best case, the cells take a dump and ruin the light, but worse case?

I only keep cells in a haldful of lights, that those that are in daily use, and only a (very) few that go in’n’out of rotation. All of the latter, though, are tailcap-locked-out.

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Long gone, no visible damage to the cell except for the split wrap and of course its spilled innards.

Au-coated spring on the tailcap and just a flat nubbin on the driver board.


(click me!)

shows the driver and profile of the tailcap.

Didn’t fall more’n like 8” and roll another 1’ or so the rest of the way.

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