credit card sized phone charger

i wanted a charger that fits my wallet

it uses a samsung galaxy mini battery (i had an old phone lying around)

it uses the circuit from the aluminium cylinder portable chargers that use 18650 batteries

i removed the large usb plug and soldered the wire to the phone directly to the board, join the green and white wires together (use the cable that fits your phone, i used a micro usb)

remove the label of the battery and solder wires directly to the protection board, the gold contacts m