How do charge controllers work?

Question

I am creating a small wind turbine, I will be using a stepper as a low-efficiency generator. I have found off-the-shelf "wind charge controllers" but would rather roll my own because I would enjoy the project more.

What is the core principle these "charge controllers" run on? I can't seem to find much information on the mechanics of them other than that they regulate the voltage & current to a battery.

Is it as simple as taking the full range from the generator (say 3-30v) and making sure the output rail is a constant voltage that the batteries can handle for charging (I.E. 12v) or is there more to it than that?

Answer 1

The answer to this one is Yes, AND No.

Cheap charge controllers can be as simple as a voltage converter (exactly like you describe in your question...see Buck-Boost Converter), but better ones will incorporate Maximum Power-Point Tracking (MPPT) circuitry to allow them to draw power from the turbine more efficiently.