I’m a cycling enthusiast, and when theweather is bad I use a bicycle trainer in my apartment. But riding to nowhere has always felt pointless. This got me thinking about how I could use my pedaling to produce electricity. By driving a generator with the movement of the back wheel, I figured I could run a lamp or charge my phone. Realistically, this wouldn’t do much to cut my utility bills (or carbon emissions), but it would give my indoor riding a sense of purpose. Besides, I was curious to see what the project involved.
To skip ahead a bit, I ended up rigging my bike to a 24-volt, 200-watt electric motor, which I modified slightly to generate electricity instead of doing mechanical work. I used the motor (now, operationally, a generator) to charge a 12-volt lead–acid battery. And, finally, I added an inverter to convert the battery’s DC current into an AC current, which is what’s needed to power anything you’d normally plug into a wall outlet, and to store power so you can use appliances even when not pedaling.