how to make a dynamo for a bike

[mtn26bkr]

Well I've been riding my bike a lot lately and I figured heck I should put all that energy to use, and it could make a good workout to power a TV by bicycle. So any advice on what would be needed for a bike dynamo would be appreciated. I'd hope to build it by hand as much as possible, but if there was a cheap buy I could go for that too.

 

[imported_Tick]

Ummm....

Firstly, how many volts do you want out?
Secondly, how many amps?
Thirdly, how do you intend to mount it?
Fourthly, how important is efficiency to you?
Fifthly, how important is power stability to you?
Sixthly, why did you put this in OT?

 

[wedi42]

you would have to ride all day to power a tv for 1/2 an hour

 

[imported_Tick]

Originally posted by: johngute
you would have to ride all day to power a tv for 1/2 an hour

Maybe like a portable TV.

 

[jagec]

Junkyard alternator,
Used car battery,
inverter from your local auto parts store.
Hook up the alternator to some kind of wheel (heavy would be a good idea...nothing like a flywheel to make up for jerky output), and make a stand that would hold the rear wheel of your bike slightly above the ground, and pressed against the alternator wheel. Use a speedometer (hooked to the REAR wheel) to monitor speeds. Hook up the battery in the obvious way. Use a voltmeter to get an idea of what gear and what speed works best for proper alternator output, then test the assembly with the inverter and a light bulb. Can you keep the bulb at a constant brightness? Measure voltage, amperage, etc. Get an idea of how long you can keep it up. Then, try using other stuff.

Note that this is primarily an EXERCISE setup...you'll never get a good amount of power out of it.

That's the cheapest way, but it's ghetto.