Originally Posted by
superpletch
I was riding the other day and my garmin flashed "low battery". my mind was wondering or wandering on how to charge devices on bicycle (cell phone, garmin, lights) the usual is a magnetic generator, either in hub or roller on wheel, which steals watts. As I was rolling along at 25mph I thought maybe a small wind turbine generator utilizing an impeller. Not being a physics major and with no data, it seems it may be more efficient than a magnetic dyno charger?
A wind turbine is just another dynamo like the ones in hubs, except that it gets its input power from a propeller. And I'm guessing here, but I think you'd need a really big propeller to get useful power out of one at cycling speeds. Then its wind drag would slow you down that much more. I'd sooner go solar.