Help - can’t charge protected 18650 above 3.8V - how do you reset the circuit?

I've got a pair of protected Olight 3400mAH 18650s, and am trying to charge one that has been lying around for a few months unused.

When I put it into my i4 the yellow lights blink as expected, starting with just one, then a few seconds later it either jumps straight to 3 illuminated indicating charging over, or flashes on 2 for a while (and it can be quite a while) before going to 3.

My DMM reads 3.8V which seems to be the limit. I have tried multiple times but once 3 lights are showing I have to leave the battery for a while before trying again or the charger jumps straight to 3 lights. It can take a dozen tries before it looks to be charging normally however it always terminates early.

I tried on my Li100 and it goes straight to termination as well.

The other Olight performs as expected in the i4, i.e. charges to 4.2V.

I suspect therefore that the protection circuit is playing up but don't know how to reset it and can't find any info other than resetting in the case of the circuit tripping due to low-voltage, which isn't the case here. I always store my spares at 3.6V or 3.7V, and this one was no exception.

Any ideas?

It is very likely, that the PCB protection is defective. If you want to use the cell further, you have to remove the PCB, or solder a new one.

http://www.candlepowerforums.com/vb/showthread.php?257162-The-anatomy-of-a-Protected-Battery

I have the same understanding. I was hoping there might be a way go rebooting the circuit. I'll keep experimenting but with no real expectation of succeeding.

A shame, I am not a fan of protected batteries but there are uses for them, in this case in a convoy S2 where there is not a low-voltage cut-off built-in.

Mind you I never discharge below around 3.4V anyway.

Led Astray said:

I have the same understanding. I was hoping there might be a way go rebooting the circuit. I'll keep experimenting but with no real expectation of succeeding.

A shame, I am not a fan of protected batteries but there are uses for them, in this case in a convoy S2 where there is not a low-voltage cut-off built-in.

Mind you I never discharge below around 3.4V anyway.

Click to expand...

I've got three S2 Convoys here, a custom S2+ that Ven sent me, an S2+ standard jobbie and a regular old S2. I might just try and discharge the battery down to say 3.0v-3.2v and see what you see. I don't run protected cells in any of my Convoys and now have 6 of them, but that's just me.

Like sbj states, just take the wrapper off and remove the PCB and see what you see, if you can't return it to Olight.

Chris

ChrisGarrett said:

I've got three S2 Convoys here, a custom S2+ that Ven sent me, an S2+ standard jobbie and an regular old S2. I might just try and discharge the battery down to say 3.0v-3.2v and see what you see. I don't run protected cells in any of my Convoys and now have 6 of them, but that's just me.

Like sbj states, just take the wrapper off and remove the PCB and see what you see, if you can't return it to Olight.

Chris

Click to expand...

Good idea, can't lose anything by trying. I imagine it's an NCR18650B under the wrapper.

I'll give it a go running it down and maybe have a fiddle with my hobby charger at different charge rates before removing the wrapper & PCB. I have no real problem using an unprotected battery in the S2, I have yet to get anywhere near a low-voltage warning let alone cut-off.