lectraplayer

Been awhile since i have been in the saddle, and when my knee heals up, I intend to hit the trails behind my house. I already have an awesome lighting system I fashioned for night use as that bug bit me. Anyway, what I am looking to do now is bogart a drill motor for a dyno. I'm an electrician by trade with a BAS in electronics, so my only question is how to drive the motor off of the wheel. I can figure out mounting but am still trying to come up with a way to spin it.

alaskanb3arcub

One way is to use a bottle style dynamo, which, if I remember right, uses friction to rub on the tire. It is not necessarily good for the tire, though.

lectraplayer

That's what I am building with the drill motor. What can I press on tge shaft of the motor to get a good grip on the tire/rim? The rim is actually preferred if we can find something "sticky".

unterhausen

the problems are so substantial that you probably should just get a commercial dyno, they're cheap.

If you can steal a motor out of a cheap battery powered drill, that might work. The more expensive ones have the motor built into the casing in such a way that it would be hard to use them. But you still need to fashion a drive wheel.

christo930

I would use a dremmell buffing wheel, but you will need a lot of tension for it not to slip. This is a really inefficient way of creating a bicycle dynamo because of the pressure needed to keep the roller on the tire. It also damages the sidewalls of the tire (and you have to use the sidewalls unless you have a really smooth tire tread), which I why I recommended a dremmel buffing wheel, to cut down on the tire damage.

Also keep in mind that your voltage is going to vary with speed. I personally think it would be (harder) but much better to build a small generator on the rim near the hub. Use a ring of magnets attached to the spokes by maybe using balsa wood and sandwhich it to the rim and then build a stator attached to the fork, but lined up with the magnet wheel (much like a homemade windmill setup). Put a small full bridge rectifier in the area directly about the bottom bracket and use a couple caps and voltage regulator to keep a constant voltage. You could easily get 10 or 20 watts out of something like this with less resistance than the bottle design you are contemplating.

Chris

lectraplayer

Certainly an idea to consider.