We don't use much electricity and what we do use, we make ourselves. We have solar panels but not many and their capacity is low. Our most reliable source of power is pedal power. We cycle to turn a generator that produces electricity that we either use immediately (the most efficient way) or store in batteries (which is less efficient but can be more convenient).

The cycle generators are mostly used to power our laptop computers on which we create and update the website. We also use the cycle generators at public events to provide educational entertainment. We used our Mk1 design at the Moretonhampstead summer fair to provide Internet access and demonstrate our website. At our camp fire event during Moretonhampstead carnival week, the generator powered a water fountain and when the sun went down it powered a projector that threw a ghostly face onto the side of Marquee. We provided a cycle powered sound system at Exeter with the Mk2 version and a week later we did the same at Tavistock using the Mk3 design.

Mk1 = Our original cycle generator is currently decommissioned having providing parts for our second attempt. It is an old blue exersice bike purchased for a few pounds from a recycling center. The design evolved, first using a single motor and then two motors linked by their shafts, and driven by a homemade rubber wheel held in contact with the bikes fly wheel. Problems with slippage and low output (it produce less than 2 amps into 12 volts) lead us to try a larger motor and a better wheel. We stopped using the Mk1 design when we found a exercise bike with a chain guard which is safer for public use and the motor on that instead.

Mk2 = This design uses a whirlpool washing machine motor driven by a fan belt over the flywheel of a modern exercise bike from the recycling center. It has all the 'mod cons'; speedo, chain guards, comfortable and adjustable seating. The pulley on the motor was turned on our pole lathe. We can get upto 7 amps when charging a 12 volt battery but 4 or 5 amps (50 - 60 watts) is a far more maintainable average output. The voltage can reach 75 volts so the generator could be used to charge 24 volt systems (or higher). We have fitted a little worksurface to the handle bars on which we can use a laptop computer while we pedal - which is what I am doing now as I type this.

Mk3 = This strange looking device is yet another exercise bike found at the recycling center for a couple of pounds. At first glance it appears quite hi-tech but it has no bearings and is therefore quite inefficient in producing electricity because the cyclist has to overcome the additional friction. It does however offer a very comfortable cycling position, is easy to get on and off and is easy to adjust. It is also light and easy to move. These considerations made it seem an ideal demonstration generator to take to public events. We used a fan belt over the flywheel to drive two motors fitted by their shafts to the same pulley. We made the wooden pulley on our pole lathe. There seems to be a problem with slippage between the belt and the flywheel. The design produces about 5 amps maximum into a 12 volt battery but maintainable outputs seem closer to 3 or 4 amps (40 - 50 watts).

Mk4 = Whats next? There are basically two possible future designs in various states of evolution at present. One is a quite traditional cycle generator that would use a racing bike with its large back wheel driving a car alternator via a large fan belt. The other is a device that would be place on the floor infront of an existing chair. It would use either a small gearbox to drive an alternator, or simply use an ex-military hand cranked generator driven by chain or directly from the pedals crank.

See also : How to build a cycle generator