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How to convert a battery pack to AC power? Answered

Wife owns a very expensive piece of Japanese cosmetic device that uses a very special Li-ion battery pack but the battery died! No way I can find a replacement for the battery pack.  The battery pack available only has 2 wires (black and red) but not 3 wires (the yellow wire). I am afraid if I get a 2-wire battery pack, it won't work at all. There are lipo battery packs, but I don't think I can replace li-ion with lipo battery packs?!

I am wondering how to convert it to an AC power?

I have no experience doing this at all, so if you can provide as many details as possible, that will be great!

The battery pack:
3 wires connected to the connector: red, black and yellow; 7.4V, 750mAh

The AC adapter used for recharging the device:
INPUT: 100VAC 50/60 Hz 8VA

Thanks a lot!


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Josehf Murchison
Josehf Murchison

7 years ago

The yellow may be the charging shutoff or a thermistor, it should be needed to charge. Doesn't mean you can't use the two wire. open the battery pack and post a photo.