This is the wind speed at which the wind generator begins producing. For all practical purposes, wind speeds below about 6 to 7 mph (3 m/s) provide little or no usable energy, even though the blades may be spinning. At best, this minimal output only overcomes the power losses caused by a long wire run or the voltage drop due to diodes. We are beginning to see high-tech controllers that are able to “store” the small amount of energy available at low wind speeds in the alternator windings. This energy is then pulsed to the batteries in a manner similar to a pulse width modulated charge controller.