Here’s a very unusual battery project shared by Misha Rabinovich on the Adafruit Forums:
In the end this worked out beautifully. We made a sweat battery out of about 150 cells! We evolved the aluminum air battery design to use a sweat-soaked paper towel instead of a vat of sweat. We grouped our cells in secondary groups of 8 to get the voltage up to about 5v, and then put 19 groups in parallel. The first day of the exhibition we had about a whole amp of power coming out! The half life of the power is about a day, mainly because of the evaporation of water from the paper towel. We rehydrated the primary cells and got the battery to power the mintyboost and charge cell phones during the whole weeklong exhibition.
It was great, thanks for this excellent kit! Big props for making the board perfectly sized for Altoids smalls tin instead of the big one.
Photos and how-to pdf with drawings of Baghdad batteries and our batteries on our blog here.
Video interviews with us about our presentation at the Ideas City festival put on by the New Museum here.
And here’s a write up at their project site:
We presented our mobile sauna in New York City and got a very great reception. People used our sauna and volunteered their sweat. We turned this sweat into electrical batteries on the spot and charged our cell phone. Here is the instruction sheet we presented to explain how it works. The full instruction PDF is here: Maximizing Sweat Equity How-to