I built this for emergency mains supply backup to keep my gas Boiler running during power cuts. The battery is charged through a car alternator. The alternator is connected by a fan belt to the rear wheel of an old bike without a tyre. An inverter steps the 12v up to 240v to power my boiler. If I stop pedalling the battery takes over so there is no interruption to the supply.

The bike is mounted on a turbo trainer with the fan removed. There is a small dashboard mounted on the handlebars to control charging and to monitor the voltage output from the alternator. The circuit uses basic electronics and a few switches.

My gas boiler uses about 80watt of electricity when running so should not be too difficult to keep running. Would also make a good exercise bike.





More details on my site here http://home.btconnect.com/brettolive..._generator.htm