Helical Twist Vertical Axis Wind Turbine - Generator Matching

[FanMan]

Hello

I have designed a vertical axis wind turbine (Savonius) with a 180deg helical twist. It catches the wind really well but the wind power to electrical power conversion is really poor, it is currently only at 4% efficiency. I think the problem is the dc motor that I am using as a generator. I currently have a no load voltage of about 4.5V and a short circuit current of 0.02A at a wind speed of 6-7m/s. Ideally I'd like 4.5V, 0.25A so that I can power a mobile phone via USB. The motor is rated at 800rpm/V. I used a variable resistor to find the peak power, this occurs with a 60Ω load resistance and is 0.07W (2.26V, 0.034A). Also I am currently using a pulley system with a ratio of 5.2:1, it is a basic pulley with an elastic band. Any help would be greatly appreciated!

Thanks in advance

 

[Danger]

Hi, FanMan;
I know nothing about the subject, so I probably won't be of any help. Just wondering, though, if you've experimented with altering the pulley ratio.