We used a home brew
wind and trolling
generator on our previous
boat. It used an old tape drive 32 V perm mag
motor as a generator, and I think this is similar to the four winds
commercial models. It did not have any controller in the circuit, only a blocking diode. We simply monitored the voltage at the
battery and turned it off if it got too high. worked just fine for years.
So, I'd suggest that you simply bypass your controller and see if there is any output into the
battery. No need for a dummy load when you have a battery to charge!
You should see a rising voltage and current as the wind speed increases. Exact values will depend on state of charge and size of the battery bank, but this test will demonstrate that the generator is at least functional. If your controller is kaput, in your place I'd simply eliminate it and use observation of voltage to tell you when to shut down (if ever!). On typical cruising
boat applications, when relying upon wind generation, really full
batteries are pretty rare and you will likely leave it running most of the time.
Jim