Plotting on making a bicycle-powered dynamo

I know, it sounds a bit Rube Goldberg (Or Heath Robinson) like, but since I can't afford solar panels, have an extra brushed motor lying around, and a junk bicycle, I thought, what the heck. I sense that energy shortages may be coming soon and I want to charge batteries to run other devices in the house without having to use fuel. Any thoughts? I am not going to use a kit btw, and may employ a local machine shop to do a few things for me. I could modify a used stationary bicycle stand for the purpose.
I might be able to milk 200 watts out of it (Definitely enough to charge lots of lead at once).

blueb0ttle2 said:

I I sense that energy shortages may be coming soon and I want to charge batteries to run other devices in the house without having to use fuel.

Click to expand...

Food is fuel.
To get significant energy out you will have to eat more. The price of food is going up so whats to gain?

Google "bicycle generator", there are several dozen examples on the web, and probably some you-tubes also. "dirty" electricity that fluctuates can be used on any resistive load. You can heat up a toaster to make your morning toast, as an example...

Toasters are pretty power hungry. My toaster draws 900w and it's a 2-slice model. I doubt 200w of 'dirty' AC would make toast very well but a 1000w inverter and a pair of fully charged 20ah SLAs will make a couple of slices (I've done it).

Looking forward to seeing what you come up with.

I have a lifecycle exercise bike, and it is exactly what you are building. The bike spins a small 30 Amp 12 volt alternator that just happens to be the same size on my Yanmar Diesel mower. My exercise load is set by the pwm level to the rotor field. The stator goes through the typical 3 phase bridge rectifier into a small resistance high power load resistor. If you could find an old lifecycle, it is all prebuilt!

I've been generating power from a bike for years - mainly in the winter months to keep in shape, then can use the bike outdoors in the better weather. I do not want to discourage you, but if you have a large battery bank, you will probably not make the strides in charging them that you'd like. My current setup is a pmg that is belt driven from a rear mounted flwheel (that takes place of the common rear wheel). I have a range of gears as load increases / decreases and the flywheel helps with electric motor starts. The output can be direct to the batteries, or go through a PWM controller which logs watts/amps/kwh.. If you are successful in setting one up, I'd be interested in any data you might have in regards to using long vs short cranks.
Good luck on this project!
- CrazyJerry

It might be handy to have some kind of control that allows you to change the pedaling resistance and still generate into the batteries. A car alternator-based system would be pretty simple to do this with.

With a permanent magnet generator, if you get the voltage constant of the generator matched to the batteries the cadence will be neary constant over a wide range of power. You'll get almost no resistance up to the point where the voltages match, then it will get really hard to make it go any faster. Gears would be handy to change the cadence.

The efficiency of the generator is not likely to be great, so the power you get out may be quite a bit less than what your legs are producing. A wattmeter or Cycle Analyst would be a very cool thing to have on board.

A direct drive hub motor would be about the easiest thing to hook up. I doesn't even need a rim or spokes. It would need some kind of diode bridge but that is pretty simple.