Ok... maybe I was thrown off by the guru in yr login name!
Huge damage to lead acid batteries by charging at double rated voltage. Also, how could you then draw at 12V while charging (i.e. while the wind is blowing)? The battery bank voltage is usually the same as what you plan the generator to make (within a few volts), unless you have an electronic circuit to convert voltages,
I think I misunderstood earlier re the blade size (you were talking rotor disk size, right?). How long do you plan the blades to be? Do you have any idea of an average wind speed at the site? Or an idea of how much power you want to generate in that wind? Give me something
to work from...