Just bought this battery at Best Buy:Rocketfish™ - DSi Power Shell with Rechargeable Backup Battery
(my BB has it for 99 cents). I don't have a DSi, but I bought this thinking it would work for my 3DS, considering they use the same charger. The battery doesn't fit, so I took it apart. Just wondering if I could use this in a project, if I solder on a charge port of some sort (probably mini USB). The way this one works is it acts as a second battery in the dsi. It goes in the slot of the dsi where the original battery would be, and then the original battery goes in a slot in this thing. Since it's designed in this way, it has no charging port of its own and uses the dsi charging port.
Wondering if anyone knows if I take a li-ion battery such as this and add solder a charger/ charging port will that charge it, or does it have to be designed to be charged in this way?