The world’s largest battery has been made using "Organic Charging" - made out of copper wiring, nails, apples, and potatoes. You’ll see a Nokia Lumia 930 in white as well as a Nokia Wireless Charger attached to a rigged-up wire connected to the food. The food that charges the phone.
The pessimist in me wants to point out the fact that these apples and potatoes will likely be tossed in the trash after this lovely experiment. The optimist in me wants to mention how awesome it is that Nokia and Microsoft - and soon just Microsoft - are inspiring the public with a science experiment such as this.
The setup here required 800 apples and potatoes in all, and was able to charge up the wireless charger in an unspecified amount of time. Likely under a day, we must expect, as the experiment could not have been left out overnight - wild animals, and all.
One big missed opportunity was that the apple/potato setup didn’t spell anything out up on the wall - but publicity is publicity.
Above you’ll also see an instruction video from TheGeekPub. This instructions manual also uses quarters and pennies for a slightly different setup. It’s all super simple.