A few weeks back I suddenly had an epiphany that my 5 year old son would be really impressed by a potato battery! So after a few failed attempts, last night I finally got a working electrolyte battery to power a clock. It was using a teaspoon of salt in a cup of malt vinegar instead of a few potatoes but was “impressive” nonetheless.
My first attempts didn’t work and I’m not 100% sure what was incorrect as I didn’t follow scientific method properly but I used:
2/3 lemons (not that fresh) with galvanised nails and 2p coins
2-4 small potatoes with galvanised nails and 2p coins
sweet potatoes with galvanised nails and 2p coins
None of them worked but I was led to believe that the amount of fruit / vegetables used connected in series would provide sufficient voltage so now I’m pretty sure it was that the 2p coins didn’t contain enough copper. (I should have used pre-1992 coins as these are 97% copper).
Last nights effort was a malt vinegar and salt solution, some zinc plated screws and some copper plumbing scraps I found in my garage. I connected 2 ramekins of the vinegar solution (about 100ml in each) in series which gave me enough volts to power the clock.