Generator from scooter motor
The generator is the motor from a discarded electric scooter ( model MY1016 from JX Motor Co., rated 24v input and 2750 rpm). I removed the motor, it’s drive chain, and sprocket wheel and attached it to the frame of a discarded bike. The pictures show the details.
By cranking furiously, I can charge a 12v battery with about 3/4 amp of current. There is a small epoxy rectifier to block the battery from driving the motor.
This thing was made from parts on hand and cost me only the assembly time. I don’t have any sources or price lists.