On one of our recent trips across the interweb we happened upon an article that discussed how to make your own windmill using a GM one-wire alternator. The link can be found here:

Do-it-yourself wind generator. Photo from www.diybullseye.com

Almost immediately we suspected that something was wrong. Anyone with a dead battery trying to get it charged back up can tell you that slow speeds, like at engine idle, will not charge anything.

We did a little searching around the information superhighway to ferret out the truth behind wind-powered generators made with Delco alternators. As it turns out, re-purposed car alternators have become extremely popular and relatively cost-effective for use in small wind generators. Who knew?

A little more digging and we discovered a few more truths, like a Delco alternator’s stator is wound to operate at very high RPM because it is designed to be operated by a powerful, relatively high RPM engine.  The operating RPM of a Delco car alternator is around three times the RPM of the engine’s crankshaft.

There are are some free designs for building your own wind powered generators online. Photo from theselfsufficientliving.com

Because a car’s crankshaft generally operates at around 1,000-4,000 rpm, a car’s alternator is designed to put out good charging voltage and amperage around 3,000-12,000 RPM. It would take a hurricane force wind to turn a small wind turbine fast enough to even start charging a battery.

We also discovered that there are modifications that can be made to a Delco alternator to make it suitable for a small wind generator. One, the stock Delco alternator stator wiring needs to be replaced with a stator that has more turns of smaller gauge wire and high powered neodymium magnets replace the standard magnets to give more power output.

Photo from theselfsufficientliving.com

If all of this seems too complicated, there is another method of building your own wind powered generator. Buy an alternator from WindBlue Power that already has the permanent magnets installed to complete the project. We did find a few useful tips and designs at theselfsufficientliving.com.