I got some airplane propellers, and went through and found which motors I had that spun fail easy and had shafts that fit with minimal modification or conversion. One is a bipolar 9V, and 2 are 12v (pretty sure) unipolar. Really clueless on how to work the diodes and phases to my best advantage. I'd be happy enough to charge 4.8 volts worth on NiMH batteries, could live with 3.6 volts, but of course more is always better. My load will be an MCU and some LEDs, nothing too heavy for the first experiment. Just want to get a feel for how much useable power I'll have. This is kind of a new direction for me, so no previous experiences. I can do a basic single phase power supply, and can probably get by with that, but I'd think I'd only by making use of maybe half of what is actually generated.

Wouldn't I need a much higher RPM to get usable power? Don't think I have any thing larger than 12VDC. I don't have a tach, but would be surprised to see 2500-3500 RPM, but it is huricane season here... Perhaps a boost converter.

Basically, I've got a box full of steppers and don't use them, only a few ideas involving steppers. This is small scale and using mostly salvaged parts. We don't get strong constant winds, usually atleast a light breeze. If I can get some useful flashing lights, might consider a much larger project.

Steppers are usually designed to offer considerable resistance against moving, even when not energized. That's probably the biggest barrier to using them effectively with low input energy.

As for rectifying them, there are some MOSFET based active rectifiers that are sometimes seen on high-efficiency switching power supplies. Later I might try to find some.

Thanks, will have a look. Sounds exactly like what I'm after on this project.

I went to the site refered to in the 'sticky' (sounds dirty...), they used a full wave rectifer on each coil, tied the outputs together in parallel. They had some interesting ideas for rotor blades from PVC pipe. Also show how to use a 3 phase rectifier from a car alternator. Lots of good stuff to think about.

I'll give that a try a little later. I was looking through parts for bridge rectifiers, but didn't find two of the same. I know I have more, but they must be buried some place with other seldom used parts.

I've got 3 steppers with propellers, but have done anything to mount them on a vane, or where I'm going to eventually mount them. Was going to do the fence posts, but the best ones are along the back alley and a little concerned about kids. Maybe roof mounts. Have done much lately, we are getting only light wind (it's huricane season here, and my air conditioner vent spins them faster).