This is meant for a 12 volt battery. The input voltage can go up to 60 volts (in theory, I haven't tried it) with around 50 Watts of input power. It is for a small wind turbine I've been working with for a while. My thought was it should cut in at around 3 m/s and cut out at 12 m/s. So if it is producing 15 volts at 3 m/s (open circuit. There would be very little current at that wind speed), it should be producing around four times that much at 12 m/s, or 60 volts open circuit. The actual input voltage would be less because there would be more current and therefore more stator loss (I have a 9 ohm stator), but that is how I came up with that design goal. The plan is to turn on the MOSFET 100% of the time and stall the turbine if the voltage gets too high. This is for a VAWT with a narrow power curve. It can stall pretty easily.