Anyone can make a free pedal powered bicycle generator with a bike and some salvaged materials. The bike generator shown here cost a total of $0 – Zero Dollars. It was all free stuff salvaged from the junk.
Whether you want to go green or power a cabin in the woods, a bike generator is the perfect device to help keep your batteries topped off during periods of clouds or no wind. If you are using solar power, you can go days at a time with no sun. If you are using wind energy, often the wind will not blow for a few days. In either case, you may need to produce some extra energy to help keep your power on.
The bike used for this project had been sitting in someone’s yard for years. It needed some oil and some cleaning, but it was fixable. The tires were dry rotted, but were removed anyway for the project. Just to prove a point, the chain was siezed up and rusty in many points, but with some oil and two pairs of pliers, the chain was freed up again. Soak the chain in penetrating oil for a few days. Then you can carefully and slowly work the siezed chain links back and forth until they move freely. (Good information in a survival situation.)
For the generator, a free treadmill was scrapped out for its motor. You can get free treadmills all the time. They are so huge, people are happy to get rid of them. They have a DC motor inside, which is perfect for a homemade people powered generator.
Any DC (direct current) motor will work for a homemade generator as long as its original voltage rating is higher than the voltage of the device you want to power. In our case, the batttery bank of 12 volts DC requires about 14 volts to charge them. The treadmill motor was rated at 90 volts DC. More than enough to charge batteries. Actually, this means that you do not need to turn the motor as fast in order to get a decent charging voltage out of it.
The frame was made out of scrap lumber found laying around. You can ask around if you do not have any yourself. The important point in making a frame is to use a long board starting in front of the back tire of the bike and extending a few feet behind the bike. This will be for the generator mount.
In the photo above you can see the side stands which will hold the back wheel off the ground. A long board goes from left to right underneath the bike to give the whole thing stability and keep the bike from tipping over.
Below you can see a pair of BMX bike foot stands, which you often find on the front or back wheels of a BMX stunt bike. If you cannot get them off an old bike, you can get them off ebay for a couple bucks.
On the image to the bottom right, you can see the rubber tire has been removed from the bike. A large “V” belt is now put on the wheel in its place. You will need to remove the wheel from the bike for this part. Do it at the same time as you replace the wheel mounting nuts with the BMX bike pegs. You will actually replace the original wheel mounting nuts with the bike foot pegs. The pegs will enable the bike to stay upright in your homemade bike stand.
Ask around at a farm for an old belt you can use. Most farmers will have a bunch of old belts laying around. If not, you can get one at an auto parts store. Measure the size you need with a long rope or string.
In the photo below you can see that a piece of angled board was cut and nailed into place to hold the bike stand steady. Secure both sides in this manner. Also important to note is that a notch was cut out of the bike stand on each side to hold the bike pegs in place.
Mount your DC motor onto the end of the long board that extends out behind the bike and run the belt around its pulley. In this case the belt fit perfectly on the motor with no modifications needed. Actually this whole project went together quite well with no extra parts or mods needed. Everything was nailed together, including the treadmill motor. Nails were driven into the board through the motor mount holes, then bent over a bit to keep the motor in place. There is no spring to keep tension, so the motor was held in place with the belt under tension while the nails were pounded in.
A flat board was placed underneath the front wheel just to add stability on the soft ground because this is an outdoor generator.
You will want to make some type of cover for the motor if you will be leaving your homemade pedal powered electric generator outside for long periods. The motor and bike both need to be protected from the elements.
You will need a charge controller attached to your batteries to protect them from over charging. Or you can use a volt meter and watch the voltage while you pedal the generator.
Here is a video of the bike generator in action: