I currently have a spare phone battery that I am using to power my child's mobile. My question is how can I add a useful way of charging the battery without removing it? Is it possible that I could solder a female USB port to the battery and mount this inside the mobile and then using a typical USB mains charger, charge the battery up that way? The mains unit only outputs 5V at 2.1A.
I'd rather ask instead of blowing a Li-Ion battery!