While riding around the neighborhood doing errands or working out in a Spinning class, a fit exerciser can maintain an output 100 to 200 watts of power. Have you ever wondered if the great workout you are getting could be put to something useful like generating enough electricity to power a television or laptop?
Your pedalling power can be used to electrify small appliances, power a boom box or be saved in batteries to use later when storms leave you in the dark. All you need is the rear wheel of a bicycle connected to a generator capable of converting your mechanical energy to electricity.
Using an electric motor from a kid's scooter as the generator, a power inverter, two capacitors, a blocking diode, an adjustable "V" belt, a sturdy bicycle stand and a bicycle from the garage, a generator capable of powering a laptop, light bulb or an electric blender can be built for about $220, said Julia Michaels, education director for the Alliance for Affordable Energy in New Orleans.
The price for Michaels' unit, while low, is inflated because some of the most expensive parts-- such as a Razor scooter motor, ($26) and a stand from a stationary bicycle exerciser ($64) had to be purchased from eBay or new. The total cost of your unit could be much less depending on how many of the parts used to build it can be found in your garage or attic, in the neighborhood or scrounded from a landfill.
Or you could just skip the build-it-your self step and buy a ready-to-use unit. But expect to pay 50 to 100 percent more than for a home built bicycle generator. And even the store-bought units require at least some assembly.
The bicycle for either store-bought or home-built does not have to be completely operational, she said. All you need is the back half: the rear wheel, the drive train (cranks, chain, rear derailleur, shifter), and a seat that can be adjusted up and down. The rear wheel does not even need a tire but the rubber rim strip should be there.
Michaels gave a presentation of a homemade bicycle generator's power to light up a 60 watt light bulb and power a boom box playing Cajun music at The Green Project, a community based organization known for recycling building materials and paint, at 2831 Marais St. in New Orleans. (www.TheGreenProject.org)
The technology is not new. In 1831 Michael Faraday discovered that moving a magnet through a coil of copper wire caused a current to flow through the wire-the principal electric motors and generators are based on. Small portable generators using human power were used in World War II to power radios on the battlefield.
There are plenty of Internet sites offering DIY bicycle generator advice and plans. Among several recommended by Michaels are: instructables.com and pedalpowergenerator.com.
While the cost of materials is low, getting a home-built bicycle generator to work reliably may take some time consuming experimentation, she said. Knowing what you want to power and how much power will be needed before buying motors, power converters and other stuff will lower the frustration level when you begin hooking the stuff up. Making friends with the neighborhood engineering geek will speed the project along.
Michaels' bicycle generator is portable enough for the slender educator to haul around to area charter schools to demonstrate how human power can be converted to electricity. She said the kids are thrilled when they realize they can light a light bulb by pedalling a bicycle--a demonstration very tolerant of the power fluctuations that can occur. Someone looking for a reliable unit to power their $2,000 laptop should probably pay the extra money and get a ready-to-use generator set-up designed to be powered by a bicycle and maybe a battery to go with it, said Michaels, who will soon be replacing her home-built bicycle generator with a store-bought unit..