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Answer a question about charging mini li-po?

benmwv

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Sep 10, 2010
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Ive been pondering an idea for a cool laser but I need to get a question answered before I start building.

If I have a small (30mah) lipo battery can I charge it from a 5v supply by simply using voltage dividers to get 4.2 volts, ~30ma and timing the charge? Or do I need to uses special circuitry?

I need the charge circuit to be as small as possible. I found a circuit that may work but I would have to change some resistor or something to lower the current.

USB-Powered-Single-Cell-LiOn-Battery-Charge-Circuit-Diagram.png


Any thoughts on this circuit, like what needs to be changed for 30ma or what the deal is with that flux capacitor looking thing coming off pin 1 of the lm3622?
 





rhd

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Dec 7, 2010
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What I do - just use alligator clips to attach the lipo to a regular li-ion charger's contacts :)
 

benmwv

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Sep 10, 2010
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That won't work for this one, max charge current is 30ma. And I need an internal charging system
 




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