Here's something you could try (and let us know if it works)
Find a basic, medium size fan. Look for one that matches the voltage of the solar charge controller on the board you're using. Check the voltage of the fan when it's spinning free in the wind and make sure it doesn't go over the voltage that the charge controller is rated for. Then just give it a shot - wire the fan to the input of the charge controller and see if it charges when spinning in the wind.