Dead quick tip - no charge
Added 2025-11-30 21:34:26 +0000 UTCI’m not sure if this is worthy of a video - but I made it anyway as I thought it might be helpful to someone somewhere.
https://youtu.be/NxtWQtaLDeQ
UPDATE: Looks like this ‘tip’ wasn’t of any use after all, as pretty much everyone here has already done this. I’ll keep this video off the main channel feed so as not to waste anyone’s time.
Comments
I had a similar issue with an old wireless phone set years ago, but it had an NiCd battery, but "kickstarting" it by putting a bit of charge in it using a power supply helped and the wireless hand set worked again!
MrHammond
2025-12-07 09:22:44 +0000 UTCOften this discharge isn't actually caused by the device in question, but by the BMS chip (battery management system) itself. Lithium cells by themselves are very stable over time, but gadget battery packs (even when removed from gadgets) will often very quickly discharge. Since the BMS is microprocessor it does need some power as well to run. They are supposed to not do that too quickly... but the implementation isn't always the best. When the battery gets discharged too much the BMS will cut off the power to everything (or sometimes blow a fuse) including itself. And the battery is officially dead. This trick works because BMS chips have a "kickstart function". You power them on by applying power to then. Since the input from the battery is disconnected, you need to go through the power output pins. If you apply a voltage and hold it a bit, the BMS will start up again, reconnect the cells, and the battery will start charging. Why the original charger doesn't do that... often chargers won't output anything until they get proper communication from the battery. So if the BMS is off it can't signal to the charger to start charging. Or alternatively - the charger boots the BMS again, sees that BMS is reporting an error (voltage too low) and cuts power before it has a chance to actually start charging.
roli
2025-12-04 16:29:25 +0000 UTCI've seen plenty of folks do this sort of thing before but it didn't occur to me until recently the process is as much to do with tricking the charger to accept the battery is viable as it is to re-energising the cell(s). Sweeping generalisation alert but most chargers won't kick in unless there's some sign of life in the battery. If you've got a 'dead' car battery that a charger won't recognise, you can connect it to a good battery, connect the charger which will be fooled by the shared power level and assuming the charger kicks in, you then remove the good battery and let the charger/poor battery do their thing. Obligatory just because you can doesn't mean you should . . .
Neil Emery
2025-12-03 03:27:45 +0000 UTC
