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Question about using LiPo Batteries

Hello,
I would like to use a 3V Solar cell rated at 45mA to charge a LiPo Battery (3.7V) rated at 200mAh. am wondering. How long should I allow this to sit in direct sunlight to charge without overcharging the battery? I would also be adding an inline switch to shut off current from the solar cell.
Here are the links to the products I would be buying (In case it helps)

Solar Cell: (Its about half way down labeled "3.0V 45mA Solar Cell")
https://www.futurlec.com/Solar_Cell.shtml

Battery (Note I'm only using one)
http://www.ebay.com/itm/2x-3-7V-240mAh-30C-Li-Poly-LiPo-Battery-Pack-For-RC-Micro-Helicopter-Air-plane-/300715147936?pt=Radio_Control_Parts_Accessories&hash=item46040502a0

Thanks

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David972 years ago

Agreed, lipos are very fussy. I have alot of them in rc cars & planes. The only lipo chargers I could find on sparkfun were 5v input. You could get 2 panels and wire them together, than put that through a voltage reg to 5v. Then use that with a charging board.

https://www.sparkfun.com/products/10217

First you will need a charge controller for the battery. LiPo batteries are vary picky about charging. So use a charge controller. don't try to time it. Next you'll need to supply that contoler/battery with slightly more voltage than what the battery puts out. 3V on a 3.7V battery isn't going to do anything.

Tuckoguy (author)  mpilchfamily2 years ago

So would something like this work?

http://www.dx.com/p/1a-lithium-battery-charging-module-blue-205188#.U27nRSh8olI

No. Look at the fully charged voltage rating on that unit. It charges Lipo batteries till they reach 4.2V. That would destroy a 3.7V battery.

Tuckoguy (author)  mpilchfamily2 years ago

If that charges it to 4.2V, would this battery work with it? it says that its output is about 4.2V.

https://www.adafruit.com/products/258

That would work as long as the battery is able to be charged to 4.2V.

Without electronics, a 3V panel can't charge a 3.7V cell.

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