One of our MAKE readers sent in this potato powered battery, the site is down now, but there is a mirror – “I built a potato battery out of 500 pounds of potatoes. It powered a small sound system. I installed the battery and sound system in the back of a U-Haul truck and drove it around town inviting people to enter the truck and take a listen….Each potato generates about 0.5 volts and 0.2 milliamperes. I connected groups of potatoes together in series to increase voltage and then connected these groups together in parallel to increase amperage. The entire 500 lb battery generated around 5 volts and 4 milliamperes. Don’t eat potatoes after using them for a battery.” [via] – Mirror & Link.