Can it be done? I tried stacking cells made with 1€ coins + 50c coins separated by some tissue soaked in sea salt but didn't measure any voltage with the multimeter. The problem is every coin except the brown ones consist mainly of copper and the brown ones are steel plated with copper. Heres the composition of Euro coins: 1c, 2c and 5c: Copper plated steel 10c, 20c and 50c: 89% copper, 5% aluminium, 5% zinc, 1% tin Centre of 1€ and ring of 2€: 75% copper, 25% nickel Centre of 2€ and ring of 1€: 75% copper, 20% zinc, 5% nickel Steel is mainly iron but the brown coins are plated with silver so it doesn't matter what the core is made of does it? My inspiration for making a voltaic pile came after watching an episode of Breaking Bad where the battery of their caravan goes dead out in the desert and they manage to get it started with a voltaic pile made from change. You'd probably need a pile the height of a house to get 12V but I like the idea of being able to produce voltage with coins all the same.