Easy charging of old 18650?

[Trekmeister]

Ok, here's the deal. I found an old laptop battery I more or less had forgotten about and decided to check the insides. Prying the plastics open I found 8 Sony Energytec US18650S(GR) arranged in a two in parallell times four in series pattern.

This battery has been sitting unused for years so the voltages of the cells are pretty bad. One pair measures as low as 0.16V, so they are probably the reason I discarded the pack in the first case. Another pair reads 1.19V, so I guess they are pretty shot too. The last two pairs measure 2.45V and 2.55V respectivley so I have some hope for these. I've seen stranger things happen. =)

Anyhow, not owning a Li-Ion charger I wanted to verify that I use the correct charging methods when plugging them into a lab cube. If I understand correctly I should charge with a constant current up to 4.20V (will probably settle with 4.00V to 4.10V for the first test-run or two) and then constant voltage until the charging current is down to a few hundreds of an amp. I recon that 1A of constant current should be fine and well below 1C, but as a precaution I'll probably go a bit lower here aswell for the first test-runs.

Comments?

If some these cells work, I'll probably have to start looking around for a nice 18650 light! =)

 

[65535]

That should work, but make sure you are testing voltage directly across the battery, those Lab power supplies, aren't always the best for regulating voltage relative to the reading. You might consider putting a digital thermometer with a temperature alarm on the battery if it gets above 120F then take it off, and put it somewhere safe.