First off, I would like to say hello as a new member and I'm glad I found these great forums. I'm helping my sister make a small wind turbine for a science project. We are using a low RPM DC motor to charge a deep cycle marine battery. My concern is what happens if the motor turns at a speed that would generate more than a 12V charge to the battery? For example, what if 40V is being sent to the battery in a strong wind? Will this damage the battery, and if so, is there some sort of regulator that will not allow more than 12V to be sent to the battery? Secondly, does anyone have any "load dumping" mechanisms that will automatically monitor the battery voltage and will not allow any additional charge to be sent to the battery once fully charged? Any help is much appreciated.