How to make a windmill to produce electricity?

How to build a windmill?

• i need to know how to make a working windmill that can charge car batteries i don't need it to be big and elaborate just too be able to run all year long and be able to run a 250 watt device for 3/8 of the year that is y i need to charge batteries so i can make a circuit of about 3-4 car batteries and i just need a set up so that when something is using electricity from it. it will send electricity from the battery but i also need so that when no electricity is being used all it does is just charge the battery so if someone could give me instructions on how to make the electricity producing windmill and then make the circuit to work the way i want it too

• Answer:

  A big deep cycle battery is better than car batteries. Does your 250 watt device need 12 volts dc or 120 volts ac, perhaps 220 volts ac. If ac, you need an inverter which draws about 10 watts from your battery, even if no ac is needed. Perhaps not a problem as a windmill can average perhaps 130 watts. 3/8 year seems like a strange request. Does that mean no electricity is needed 7 months out of the year or the appliance runs 37% of the time? If the latter 130 watts is about what you need, average to keep the battery charged. If you live in a cold climate ice and snow may disable your wind mill for months at a time. Neil