The new 500 watt wind generator, after months of designing and testing on a rooftop environment, has now been installed at our beachfront Volunteer Community EcoCenter for real world testing. Providing electricity for the lighting, communications, and power tools this generator has proved to be part of a strong and reliable electric generation system. The field testing has also provided the opportunity to test the pivoting tower installation, the tower base assembly, blade angle adjustments, special low power 12VDC and 220VAC lighting, different power inverters, waterpump , the overcharge protection circuit, and test battery reserve capacities.
The 1.2 meter blades are made from fiberglass using a NASA design to maximize the efficiency of the blades to produce power at a fairly high RPM. The original blade design had proved difficult to mass produce, and less reliable than the final design. The following are design features of the blades:
- 1.2 meters in length
- 8:1 tip speed ration
- Carbon Fiber or Fiberglass construction,
- Stainless steel core from tip to mounting bracket to prevent blade disintegration in the event of a bird strike or other blade failure.
- Solid resin, using the highest strength resin available locally
The 500W generator assembly proved to be capable of producing more that 500 watts in strong wind . This site has mild by consistent wind, and proved to be an ideal location for a personal power unit such as this. We changed the angle slightly on the blades to produce the desired RPM, and found that on many days the unit provided more power that we were using, and had to use an overcharge protection circuit. The Nissan hub assembly proved reliable and smooth, despite the harsh daily salt water breeze. Though the unit overall did show some oxidation quickly, which we have addressed in stronger metal finishing using epoxy paints, the hub assembly remained in excellent condition.
The electrical system also proved to be excellent for general use. Using two 12V automotive batteries in parallel provided a reasonable reserve capacity of about 130 amp hours. The battery bank could have been larger had we had more electricity demand, but with our conservation efforts (including 5W 12VDC LED flood lights) we found it unnecessary. Even when using power tools as needed in construction at the site, including an electric drill, jig saw, and electric spray paint gun, we did not deplete the dual batteries. We tested several inverters, and have found all of them to be overrated. A 500 watt inverter will not consistently deliver 500 watts.
