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How do I charge Li-ion Batteries? Answered

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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prenato

6 years ago

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

http://www.youtube.com/watch?v=A6mKd5_-abk

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...

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steveastrouk

6 years ago

Charging any batteries in parallel is usually a bad idea.

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makincoolstuffsteveastrouk

Answer 6 years ago

ok, so say i just want to charge them all seperately, how would i do it?

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steveastroukmakincoolstuff

Answer 6 years ago

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.