How to Build an Electrical Generator for Your Bike

There are many different types of electrical generator available, however most of these work by burning fossil fuels which are in short supply. Building an electrical generator with a bike is one of the cleanest ways of generating electricity. It is however one of the most difficult.

All generators work in a similar way, they rotate a magnet through a coil of wire. This causes something called electromagnetic induction which induces power in the wire. Normally this is done by using a gas motor, or in the case of power stations by boiling water which will turn the turbines.

A much greener solution however is to use your own pedal power to power the generator. This means that your own energy is being converted into electrical energy.

Step 1 - Finding a Suitable Motor

First you need to look for an electric motor which is suitable for use in your bicycle generator project. This should ideally be a 12V DC motor though you could also experiment with using different motors. You will be able to either buy one of these specially or alternatively you could take apart a washing machine or similar appliance to salvage the motor.

To make peddling easier you will also need to use a gear. Again the gearing is something that you will need to experiment with to get the best results.

Step 2 - Measuring

Spend time measuring the size of the motor and the size of the bike. You will need these measurements so that the bike can be supported and the motor secured.

Step 3 - Making the Frame

The bike will need to be supported off the ground so that it doesn't move. The drive wheel (normally the back wheel) will need to be lifted up so that the energy can be used to provide electrical power rather than being used as kinetic energy.

The frame can be made out of sheet metal or plywood depending on what you prefer. Plywood is however much easier to work with. Cut a hole in the plywood so that the wheel will fit through, the hole needs to be large enough to allow the wheel to spin freely. The same frame can then be used to mount the motor on. The motor needs to be bolted securely to the frame in line with the wheel.

Step 4 - Gearing

A large plastic roller or gear needs to fixed onto the spindle of the motor. This will press against the tire on the wheel. The friction between the two will cause the motor to turn which should generate electricity.

Step 5 - Connecting the Load

The load is whatever you are running off your bicycle generator. This simply needs to be connected to the terminals on the electric motor. As the electric motor spins it will work in reverse which will generate a current.

Step 6 - Battery Charger

The problem with bicycle generators is if you slow down peddling then your appliances won't get the power that they need. That's why many people will use this power to charge a battery. If you want to use the power you generate to charge a battery then you will need to connect a diode in between the output of the motor and the battery. A diode will only allow electricity to flow in one direction which will prevent charge being lost from the battery.