My most recent project was to let me see what was going on with the turbine from my house 250' away. I constructed this box which contains two 48 volt battery monitors, a combined Watts/RPM meter and a turbine shut-down switch. All this info in a decent box mounted directly below my weather station and next to my patio doors looking out at the turbine. Today the wind was light so you can see battery voltage is down as well as Watts and RPM.
The Watt meter still needs a bit more calibration when weather warms up, 8 degrees F this morning in western NY. I have a digital watt meter out in battery box so will have my wife relay watts as I watch this gauge, then will make a new template. Not to far off now. I used the plans off Hughes site for the RPM/watt meter which were quite easy, to drive a millivolt gauge thru a potentiometer for full scale calibration.
The volt meters are off ebay, with one driving from battery and other at the inverter in house to see voltage drop. I have lots of drop because right now I just have 6 AWG from 48 volt battery to house and if I pull more than about 600 watts my inverter trips out on low volts. TriStar60 controller is in house also and it all works fine unless the grid power fails and I try to run too much on inverter. Have some 4/0 aluminum to use as the ground when warmer weather hits. Will use 6AWG x 2 as the positive.
Shut down switch powers a big 120volt AC double pole relay out with battery. Relay shorts 3 phase from turbine and 48 volts DC powers the 120volt AC coils. Break the 48 volts and relay shorts turbine. Works great. Two phases of turbine AC, battery voltage and relay coil wires all go thru one CAT5 cable to house. Works fine as current flow is minimal.
As DanB says, lots of fun for a winter project.
