If you live in an area with consistent wind, wind turbines are one of the best options for a renewable energy system. Wind power can also be an ideal addition to a solar power system, since many areas experience more wind during the winter months when sunlight is at its lowest. Wind turbines are also a popular and very useful addition to a marine power system, allowing a boat's batteries to charge even when shore power isn't available.
Wind turbines are relatively simple machines. A wind turbine is basically an alternator driven by a propeller. When the wind blows strongly enough to turn the propeller, the alternator produces electricity. Then a load diverting charge controller charges the battery bank, and diverts excess current to a secondary electrical load.