Every kid who has been to a science fair knows that you can make a battery with a lemon, a potato, a penny and a nail. I've never done this and I'm not entirely clear on how it works beyond a hazy recollection of undergraduate-level chemistry class; but I gather that you do not need to use a lemon and potato as your power source but can in fact use any number of substances willing to donate or accept electrons.
My question is this: are there any home-made batteries that can produce sufficient electrical energy that its cheaper to make them yourself rather than plug your appliance into the wall or use store-bought batteries
I realize that there are a number of variables here that might make a significant difference in whether its cheaper to use established electricity sources or create your own so for arguments sake lets say that I am trying to: - charge a cell phone/laptop - run a microwave long enough to make popcorn - keep a refrigerator cold
Lets also consider the dual possibilities that I: - live in a city apartment and have to buy all my fuels and materials - live on my own far where I can grow as much produce as I want to devote to making batteries
If there are other good fuel sources that could be a logistic variable; let me know in the comments so I can edit the question accordingly.