General Li-ion safety

[alexandrul]

Re: 18650 maintenance questions

Silverfox already indicated there is nothing Grey about a cell that is sitting at 2.8v after the load is removed. Meaning they all sound like a waste of time to deal with.
They could "work" but if they are bad, they could cause problems when charging or using at high discharge rates. So at the least you should not trust them at all. I have slowly re-charged cells that were low, and it is quite a waste of time to deal with them. Experimenting is fun though if you can do it all Safely, and have nothing to lose.

I saw that Xtar WP2 II can charge cells below 2V, but I had no idea how dangerous such cells can be, so I had to ask
Thank you for your patience, I was 100% noob on this subject until last week.

Below 2 volt the charger charges with about 0.5 mA, this is enough to reset a protection pcb (Note: The led is green).
Between 2 volt and 3 volt the charger charges with about 80 mA.
Between 3 and 4.15 volt the charger is applying regular charge current (See curve below).

As VidPro mentioned it looks like they are all crap.

However, if you want to play and don't mind the dangers involved...

...

Thank you very much for the very clear instructions, I will give it a shot with an Xtar WP2 II, under constant supervision. While it might be a waste of time in the end, it will be educative (and it's better to experiment with these recovered cells than with more expensive ones).