Specifically i got a hat with Bluetooth headphones built in, but the battery life on them is shot. I've removed them from their original hat and have a slightly better one planned (without the big Bluetooth logo on the side... Don't need everyone to know). So question is, when replacing a 3.7v rechargeable cell, do i need to get an exact match on the chemistry? Like li-po/li-ion/imr, whatever? It will probably be an old cell phone battery, so will be an upgrade in both capacity and output potential, but still rated for 3.7v. Concern being if it will still be safe to charge via usb. Thanks for any help via /r/DIY http://ift.tt/2fVQHmN
