Looks like somebody managed to transform 500lb of potatos into a functional battery. According to the inventor the battery is powering a sound system. From Latteier.com-> Batteries work by allowing electrons to pass from one electrode to another. In this case the potato provides phosphoric acid, which enables a chemical reaction causing electrons flow from copper to zinc. The zinc came from galvanized nails and copper came from small pieces of copper. You don’t have to use potatoes; any acidic medium such as citrus fruit will work. More pics->
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.