At one end of the chain, you’ll have a free zinc nail and at the other end, a free copper wire.
Attach an alligator clip lead to the free zinc nail and the other end to the USB cable’s negative wire.
Attach another alligator clip lead to the free copper wire and the other end to the USB cable’s positive wire.
Charge Your Phone:
Plug the USB cable into your phone.
The electricity generated by the potatoes should start charging your phone. Keep in mind, this is a very low power source, so it will charge slowly and may not fully charge your phone