Whether you build your own, or buy one, you will need some sort of controller for your wind turbine.

There are lots of charge controllers manufactured for solar and wind power systems. Any company that sells alternative energy stuff will have them. There are also always lots of them for sale on Ebay.

What’s a Charge Controller?

Basically, the general principle behind a charge controller is that it monitors the voltage of the batteries in your renewable energy system. The controller either sends power from your homemade wind generator into the batteries to recharge them, or diverts power coming from the wind generator to another place. This only occurs if the batteries are fully charged (to prevent over-charging and destroying the batteries).

We are assuming you are using a 12 volt battery system for the purposes of this discussion.

When your homemade wind generator is in operation, the wind generator is connected to the controller. Wires then run from the controller to the battery.

When you use power to run some appliance, say your TV, the power is then taken directly from the battery. If the battery voltage drops below 11.8 volts (you can set this on the controller), the controller switches the generator power to charging the battery. If the battery voltage rises to 14.5 volts (again, you have to set this), the controller switches to dumping the generator power into the dump load.

Usually, a water heater, or some other small device is used as a dump load. There are switches to adjust the voltage levels at which the controller changes between the two states of charging. A 11.8 and 14.5 volts as cut-in and cut-out voltages are recommended after consultation with battery experts.

There are two LED lights on the charge controller. When charging the battery, one LED is lit. When the power is being dumped to the other load the other light will be lit.

Usually the system runs pretty automatically and the LED lights gives us easy feedback on whether our renewable energy system is performing properly, and what it is doing right then. When the wind is really blowing more current goes into the batteries, which means more load on the generator. The system pretty much governs itself.

In a storm the force of the winds wind can get pretty dangerous. Switching the controller to dump power into the other load does a good job of braking the homemade wind generator and slowing it down.

Warning: the whole blade and hub assembly can swing around and knock you on the head if you are not very careful and the wind changes direction while you are working on it.

Next post: Wiring The Wind Generator. Stay tuned