Have you ever wished that you could recapture that energy spent on exercise for more productive purposes? Well, you can do so quite easily by building a bike generator. Although an initial investment is required it will pay for itself in electricity saved if you regularly exercise on your bicycle. Read more if you'd like to learn about how useful one can be and how to build one yourself.

How useful is a bicycle generator?

The primary question most people have is how useful a bike powered generator can be. Luckily with a bit of math we can determine almost exactly how much pedaling it will take to power any electronic device. The first thing you need to do is calculate how many Watts the device you'd like to power consumes. This can be obtained by multiplying the voltage by the amps. Both of these values can be found on the case or power cord of your electronics.

The average rider will be able to generate somewhere between 75-150 Watts at a moderate pace. If you're in good shape and ride bicycles regularly you'll probably be able to sustain 200 Watts and even reach 300 for very brief moments. For the following example let's use a 50 Watt stereo and a rider generating 100 Watts.

100 Watts (rider) * 1 Hour = 50 Watts (stereo) * X hours?

Some basic algebra gives us...

1 Hour = 100 / 50 = 2 Hours

This means you could power that stereo for 2 hours by riding your bike generator for 1 hour. Not bad at all. However, you have to realize that there will be some loss in the system. Every component like the batteries and inverter will lose some of that generated electricity. Overall you'll probably lose somewhere around 20%. So, in the end you'd be able to power that stereo for something like an hour and a half ((100 - 20) / 50).

How can I build a bike generator?

Construction is actually pretty easy once you've got all the parts needed in one place. You'll need a bicycle, bike training stand, DC permanent magnet generator, charge controller, deep cycle 12V battery, and an inverter large enough for the load you'll be placing on it.

The bicycle gets mounted into the training stand with the rear while contacting the generator so that when it is turned the generator is spun up as well. Next the generator's output should be connected through the charge controller to the battery or batteries if you're using more than one. This will prevent over and under charging (charge controller) and allow you to store energy (batteries). The battery is then connected to the inverter which will turn the DC power into AC for common electronics to use. Also, the inverter will have a regular plug for you to connect devices.

If you want to power a 300 Watt television you'll need at least a 300 Watt inverter and going over is a safer bet. Also, since you can't generate 300 Watts while pedaling that is why you use the batteries to store up energy. Adding more batteries will allow you to save more energy and higher inverter Wattage will allow you to power large devices.

I hope this article has helped you understand how useful a bike generator can be and informed you on how to build your own. Good luck and enjoy your new recaptured energy.