Bike Generator Project


Carroll Hill School in Troy NY. has a Morning Program where the kids learn about different topics of the day. The month of April is focused on the Environment. We thought it would be interesting to discuss energy and resource conservation. A active demonstration would help explore the issues.

The majority of energy in the United States is derived from fossil fuels. According to the US Department of Energy it was estimated that 37% of the nation's energy came from petroleum, 22% from coal, and 24% from natural gas. Nuclear power supplied 8% and renewable energy supplied 7%, which was mainly from hydroelectric dams although other renewables are included such as wind power, geothermal and solar energy.

There are many simple things you can do to reduce your family's energy usage:

We decided to build a pedal power generator that the kids could use to compare standard incandescent light bulbs and more energy efficient compact fluorescent light bulbs (CFL). It would provide active exercise and hands on experience with how much effort it takes to generate electricity.

According to If every American home replaced just one light with an ENERGY STAR light, we would save enough energy to light more than 3 million homes for a year, about $700 million in annual energy costs, and prevent 9 billion pounds of greenhouse gas emissions per year, equivalent to the emissions of about 800,000 cars.

An ENERGY STAR qualified compact fluorescent light bulb will save about $30 over its lifetime and pay for itself in about 6 months. It uses 75 percent less energy and lasts about 10 times longer than an incandescent bulb.

Different Types of Lightbulbs

How to Compare Lightbulbs

There are several ways to compare bulbs:

Incandescent (watt) Fluorescent (watt) LED (watt) Brightness (lumens)
15 * 4 90-160
25 4 6.8 210-281
40 9 6.8 300-550
60 13 13 765-900
75 19 * 1200
100 23 * 1600
125 30 * 2100
300 68 * 4200

* Not available

Beware of the "100 watt equivalent" labels on LED bulbs. Look at the number of lumens!


Light Board Movie Floating Ball Movie

How it Works

Pedaling the bike spins the DC motor at around 2000rpm. The motor acts like a generator. This particular motor outputs 5-16VDC depending how fast it spins. The DC voltage is connected to an inverter. This device converts DC voltage between 10.5VDC and 14.5VDC into 110VAC. It "whistles" when you are below 12VDC and cuts out when you exceed 14.5VDC. The 110VAC is connected to eight pull-chain light sockets. The more lights that are turned on, the harder it is to pedal.

With this system we have two 40watt incandescent lights and six 9watt CFL light bulbs. Usually you have to start with one light and turn the others on slowly. It is too hard for a person to pedal consistently to turn them all on at once.

Building a Bike Generator

Parts Required

Building a Light Board

Parts Required

Building a DC Floating Ball Display

Parts Required