Today I went out there to try and charge my roughly 40 ah 12v battery with my pvc windmill. The paper said 7-14 mph from the NNE, which is the perfect direction for my back yard.
So a few minutes later, I trudged through the snow with my battery, many wires, diode, and a folding lawn chair (the folding chair was a good idea to set the battery on, except for when you try to unfold it while balancing a large 12v battery in the other hand so the cardboard box that the 12v is in wouldn't get wet). The blades were starting up on their own, so I knew there was some potential. Once I got her all hooked up, I stood there for about 75 minutes.
The peak amperage which I saw was 1.89 amps, which was a decent breeze, maybe 18 mph peak. The voltage on the battery was probably past 13v, as it was charged with my solar panel last week. So an estimated 25 watts would be fair.
Some of my observations included a moderate shake to the tail at 15+ mph, which means the blades must not be very well balanced. Also, the mud around the pole was pushed out about 4-5" from it leaning over. This concerned me a quite a bit, but not surprised as the water table was even with the ground. Maybe this summer I will pile some more dirt around the pole so it doesn't sway so much. The blades and the treadmill motor seem to be holding up just fine from the snow, ice and rain.
I am surprised that the 35+ mph winds haven't knocked it over, maybe the tower bends so much that it kind of self furls.
Hopefully spring will bring some stronger winds, as the blades have only spun on 4-5 days since January. It seems that start up is around 10v wind speed, which I would guess to be 10-12 mph.
I hope everyone had a happy Pie day yesterday!