The reason why I am asking is… because I do have quite a bunch of them that are at 0V from laptop salvages. Reading around some old posts, it seems like in some cases it can be boosted back to life, so I figured maybe I should give it a shot!
Have you done it before? How did you go about it?
What I’ve read included things like:
1) hooking up the battery to a current generator set to a very low 50ma.
2) connecting the battery in parallel to a good battery, and slowly “jolt” it back to a more recoverable voltage using quick pulses.
3) by using a hobby charger, charge it up using the NiMh mode that ignores the low voltage cutoff
4) Apparently the Xtar SP2 seems able to do it too, but at 0.7ma (not even 1ma) I reckon it is going to take days just to wake a cell up, so perhaps I can do it faster
If it is discharged that far, the cell is damaged and cannot be trusted. Also, even if you can charge it to 4->4.20V the capacity is going to be a tiny fraction of what it was, and the internal resistance will be higher. When a new, top of the line cell is less than $10 why risk it?
If the batteries are 0 they are no good. Even if you managed to charge them up they would not perform well. Why bother. Unprotected batteries are cheap. I salvaged some 5 year old sanyo batteries which were above 3 volt. They don’t run for very long and I would never use them in multi cell lights.
Wow, reading all these stern warnings posted, I suppose it is a really bad idea…!
I’ve managed to befriend an local exporter of old laptops and he agreed to sell me old laptop batteries for a buck or so each, much cheaper than I can otherwise get them from eBay at, so I guess I don’t need to be so hardup about getting every last cell to work now! I’ll give it a shot and document it as I go along for other BLFers who might like to go this path to get their cheap 18650 fix
