Here is something that might be of interest to readers of GEM. It's a wind charger that I built in the late 1920's before Rural Electrification and used for quite a number of years. It was mounted on a 40 foot windmill tower using an old windmill head with crankshaft and wheel removed, and a piece of shafting turned down to fit Model T front wheel bearings clamped in place of a crankshaft.
The generator was 6 volt with third brush set for maximum output and was driven from 18 inch V pulley. Propeller was made from a piece of fine grained fir 2 by 8 inches by 8 feet long. Pitch was about 6 to 1 on outer 2 feet gradually changing to about 4 to 1 near the hub. It would charge in a very light wind and supplemented the generator I drove from milking machine engine to provide current for lights around the farm (6 volt car headlight bulbs), radio, and a home brew electric fence. Propeller should be perfectly balanced and given several coats of hard drying spar varnish. Even then there will be considerable erosion due to running at high speed. It would sometimes vibrate when wind direction changed suddenly. This however was not due to being out of balance but to gyroscopic effect. A revolving contact was provided at bottom of mast pipe so it could follow wind direction without twisting up leads to battery in house. Generator cut-out was mounted on charging panel along with ammeter and could be shored around for motorizing and testing of generator.
I built several of these and also several neighbors built them and all were very successful. Eventually I replaced the original propeller with one having a different pitch, which I found to work better. Some need for speed control may be found necessary, depending on what windmill head is used, but I found that by setting the counterweight partly out on a pipe proved to be ample in this particular case. An alternator from a modern car I would imagine might be used with still better results. The speed step ratio on this particular one was 6 revolutions of generator to one of propeller.