I joined permies becuase I wanted to share my rocket style stove design, but since I'm now a member and I saw that you guys are into alternative evergy also, I wanted to share my old doomsday exercise bike. Its very simple and made from discarded/upcycled materials, like most of my builds/projects. It is not a permenant magnet set-up, its a regular car alternator which needs excitement from a battery, which is fine because it has to be hooked up to a battery to be charged anyway. The power needs to be stored for future use, so you will need a battery regardless.

Very simple, nothing fancy, straight to business. I used it a few times for testing and development purposes, but its put away now for emergency situations, in which case it will charge a battery or bank, to be hooked up to a small inverter for emergencyt power, cellphone charging, or lighting.

My original idea was to drive a treadmill motor, they have less drag and permenant magnets. My neighbour wanted to scrap her old treadmill and she said she would put it outside for me, when I got there the next day, her landlord had taken it somewhere for disposal so I used a regular automotive alternator for emergency use.

All I did was start with a sears/canadian tire retro exercise stationary bike, removed the solid rubber tire from the wheel, mounted a compact one-wire alternator where it was out of the way, compact rather than bulky or sticking out, and functional within reach of a drive belt.

I made a small tensioner at the alternator mount, and the wheel is also adjustable like a regular bicyle for primary chain drive tension.

When the alternator is excited with 12V, its like pedaling uphill with a fat chick on the handlebars, its not easy to pedal, but I can generate 13+ volts immediately and I'm a small guy who could be more muscular. For strictly emergency situations, it works well.

The speedometer still works when you are peddalin, and the original tensioner that used to press on the solid rubber tire, still functions and presses on the drive belt for extra tension if you chose to engage it also for extra exercise fun lol.

I'm glad you like the concept.   Ive recently come up with some ideas for another one of these.   I picked up another exercise bike and I want to make another generator, however I don't want to use an automotive alternator.  This next one will have either a treadmill motor or washing machine motor for a generator.   Otherwise I will remove the tire again and place magnets around the wheel, with pickup coils or ironies coils mounted on the frame.   Thanks for following 😃