Step 6: Tape and Finish.
You did it!! You have made your own penny battery. And it hardly cost you a dime (BAD JOKE) Just tape it up if you wish to keep it together. You can also add an LED to make a flashlight, use a multimeter to see how much voltage you get, or see if you can power a mini fan in the summer. Also, if you want to power something bigger or just see if you can make it better, try adding more pennies, it should create more voltage if it's an efficient design.