“Burning hot” and “after one hour it still is so hot that you can only touch it for a couple of seconds” is not what you want to hear when it comes to LiIon cells. Remove the cell from your home right now and put it somewhere where it cannot start a fire (bucket of sand etc).
It’s very likely defective (internal short) and a fire/explosion hazard now. Do not charge or use again!
Definitely not normal, and yeah, put it outside in open air on something not flammable. I’d contact Acebeam and share that Flir photo…maybe a photo of the battery in a safe bucket of sand, too…kinda doubful that they will replace it (everyone balks at consumables) but maybe they’ll take care of you.
Has the battery ever been dropped, or had the + terminal crushed in a little bit? The charging/protection circuit board that is tacked onto the top of the cell is semi-fragile and it’s not too hard to damage them…dunno if rough port handling could cause an issue something…could just be a defective board that finally gave out. The blue light may mean something to them so be sure to mention that. I only have a couple of usb cells like that and thus far just normal operation although I don’t use them much at all.
If you need to get a new cell, you don’t have to use Acebeam’s model. I see that’s a 76mm cell (70mm for the cell + added height of the circuit board). Not sure if the light will take normal flat or button tops cells but it might - if not then probably any protected cell with or without the usb charging port will work fine since they’re a few mm longer than stock cells. Nothing special about this one, though. Liion Wholesale and Illumn are both good sources for quality cells at fair prices and they’re BLF supporters with good & smart people working there.
One good thing here is that your hot spot is showing a temperature that is considerably lower than the danger zone around 80°C, and even that is a threshold where nothing may happen. But this isn’t good and better safe than sorry…let that thing self drain, cover the ends with tape, and recycle it.
Thanks for all the answers, i’ll get in touch with acebeam and see what they say.
Regarding the battery, i put it outside in a cooking pot over night. With a little bit of thermalpaste i also managed to put a heatsink on the pluspole. Its now slowly discharging itself while staying slightly warm, i guess there is a short circuit in the charging curcuit or something. I’ll definetly get rid of it, as soon i am sure that it is not a hazard anymore.
Also the battery was never dropped and is in a very good condition from the outside. The only thing different this time was the USB charger and cable. I dont know if its possible the a new charger and cable witch work fine with every other device i own, could have damaged the charging curcuit.
The 12 months is the voluntarily warranty they are giving. I am assuming in case of a battery literally getting hot like that, they will hopefully be more amendable to a recourse. Best of luck man, this is pretty scary!
I wouldn’t imagine that the power source or cable could affect it this way…board should have current/voltage control on it to prevent overage - usually any troubles would be the opposite to where you just get less charging current like from an old usb2 port or a low powered old wall wart or something.
Definitely let them know, though…might be interesting to see if they share any info about the blue light, but they also need to know there may be issues with the product.
If you want, you may be able to rescue that cell. Once it’s drained and cool, just unwrap it and carefully snip away the protection board (likely connected with thin nickel strips on the top end but could have one running up along the side from the bottom of the can to the top). Clean up the cut nibs, rewrap it, and put it on the charger - it’s likely still a healthy cell and for 21700 these days, draining it below our low target 2.5v for a short period shouldn’t hurt it terribly (being there for weeks or months is bad, though). This is assuming is was a board/electonics issue and not a bum cell that had an internal short. Could also see what OEM cell they’re using, too, which is always interesting to know. You can get the wraps for cheap at Illumn or Liion or 18650 battery, amazon, etc…and way cheaper from aliexpress either precut or by the meter, all kinds of colors…hair dryer will do fine.
While that’s certainly possible I don’t think rescuing a cell is worth potentially burning down your house when charging that cell in the future. It might have taken damage by the shorting and it’s not really possible to rule that out.
Well, if interested, you rule it out by charging at a low rate, observing, letting it rest and taking voltage measurements over a day/week/month to see how it’s doing, and watch it on the next couple charge cycles as well. It may be trash but it may be a very healthy cell still, too. With 18650, depending on the cell, I’d still try it myself but would have lowered expectations of success. I do take safety quite seriously but you know, flames aren’t easy to produce, and a single cell (i.e. not in series or in a pack) is far less risk, and we’re not talking dangerous gasses from lithium metal primaries like all the past CR123 episodes (which were terrible). Doesn’t hurt to give it a smart shot as long as you have a charger and meter and a little time.