Watch won't charge

[Techbrology]

I left my bangle JS in a drawer for quite some time as the screen was broken. I recently tried to charge it but it wouldn't charge. I use the g.dump() And found it was 0% but when plugged it would not show it was being charged. Is there anything physical that I can do since it's already opened up to fix it?

[gfwilliams]

This is a Bangle.js 2?

So you're saying that the watch actually boots up ok when you apply the charger, but it doesn't appear to charge the battery?

When you unplug the charger, does it keep working or just turn off immediately? What if you leave the charger plugged in for an hour or so? Sometimes it may also help if you warm the watch up slightly (at least ensure it's not freezing cold).

As you have it apart it might be worth unscrewing the PCB, and then checking the voltage across the battery contacts with a volt meter (they are down by the charge port on the underside of the PCB: https://www.espruino.com/Bangle.js2+Technical#pcb). Be careful as you have to take the PCB out bottom-first because of the aerial at the top.

Normally the battery protection circuit will shut off power when the voltage gets too low, then when you re-apply power the charger starts trying to charge and that's enough to get the battery protection circuit to go again.

I haven't seen this on the Bangle, but on some batteries if the charger can't recover them, applying slightly more power yourself can do it. It's possible that if you applied a bit of power (let's say 3.6v at 200mA) to the battery terminals on the PCB, that'd bring it back to life.