How do I charge Li-ion Batteries?

I have lots of old Li-ion batteries and I want to use the for a project. I want to put them all in parallel in a big pack and I need a charger that can charge them in a reasonable time. Can I just put 3.7v straight into them, with a current limiter of course, or do I need some special circuity with transistors etc. 

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prenato4 years ago
There's an excellent video tutorial on this subject from Dave at the eevblog:


As Steve mentioned above, charging Li-ion batteries is a bit more complex than other rechargeable types such as NiCd and Lead-acid. Fortunately there are ICs specifically designed for this. I tinkered with the idea of re-purposing an old charger for this purpose. You would have to identify the IC inside and make adjustments if needed though...
Charging any batteries in parallel is usually a bad idea.
makincoolstuff (author)  steveastrouk4 years ago
ok, so say i just want to charge them all seperately, how would i do it?
Build a specifically Li-on battery charger. The charge process is complex, and must terminate at the right point, or Re-Des video will happen.
makincoolstuff (author)  steveastrouk4 years ago
okay, guess ill have to take the hard option, damn. thanks anyway
Re-design4 years ago
Put them out on the drive way away from cars etc and charge away.

Watch this video to find out why.