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Envirotek V20 VAWT Generator
Find out more about the Envirotek V20 vertical axis wind turbine (VAWT) generator
The Envirotek V20 is a new small vertical axis wind turbine (1) (VAWT) battery charger. The three vertical axis wind turbine blades (2) drive a 20 watt permanent magnet generator (3). The generated AC electricity is then rectified (4) into 12V direct current, passed through a 5A charge controller, to then maintain the charge on a 12V battery or battery bank (5). This is a Savonius (6) type wind turbine.
The rotor sweeps an area of 26cm wide by 60cm high (= 0.156 square meters). Therefore (according to the calculation of wind power (7)) there is around 8 Watts of wind energy available in a 10mph wind, and around 60 Watts in a 20mph wind. However VAWT type wind turbines are inherently quite inefficient and so no more then 20-30% of this wind energy can be exploited and sent to the batteries.
Specifications
According to the Envirotek V20 information published in 2007 the following daily (24hrs) 12V charge rates are possible:| Wind Speed | Charge Rate/day |
| 10mph | 3 Ah |
| 20mph | 8 Ah |
| 30mph | 20 Ah |
| 40mph | 30 Ah |
These seem very reasonable - e.g. 3 Ah at 12 Volts in 24 hours equates to a current of 0.125 Amps and a total power output of 1.5 Watts (19% efficiency).
However, these charge rates have been changed in the 2008 Envirotek specifications to 6Ah for 10mph, 16Ah for 20mph, and 40Ah for 30mph - i.e. all have been doubled suggesting that this wind turbine is approximately 38% efficient, a claim which would need further testing.
Envirotek Wind Turbine Costs
Envirotek are selling this unit for under £300 (without batteries but with a 6A charge controller) suggesting use with caravans and trailers, cabins and farm buildings, electric gate openers, water pumping, and moored craft for keeping 12 Volt battery (8) systems topped up with power. A turbine of this size would not be much use for applications where batteries are regularly drained and need full recharging, but is perfect for occasional use applications such as the electric gate opener mentioned where batteries need to be constantly topped-up with power.Cost wise this is quite an expensive unit for what it is. With average winds of 5-10 mph typically in remote UK areas, the 1.5 Watts of generated wind power could be replicated using a 15 Watt or larger PV Solar Panel (9) available for around £80. However, if the size of the rotor could be doubled and permanent magnet alternator scaled accordingly this system would be more competitive - particulary in windy coastal and high locations.
Buy an Envirotek Wind Turbine
The Envirotek V20 is currently being sold on eBay UK (10) by epe1958 (11) with a £295 Buy It Now price.Web Link References
(1) http://www.reuk.co.uk/VAWT-Vertical-Axis-Wind-Turbine.htm(2) http://www.reuk.co.uk/Vertical-Wind-Turbine-Generator-Blades.htm
(3) http://www.reuk.co.uk/Permanent-Magnet-Generator.htm
(4) http://www.reuk.co.uk/Bridge-Rectifier.htm
(5) http://www.reuk.co.uk/storage.htm
(6) http://www.reuk.co.uk/Savonius-Wind-Turbines.htm
(7) http://www.reuk.co.uk/Calculation-of-Wind-Power.htm
(8) http://www.reuk.co.uk/Interconnecting-Batteries-for-Battery-Bank.htm
(9) http://www.reuk.co.uk/solar.htm
(10) http://rover.ebay.com/rover/1/710-53481-19255-0/1?type=1&campid=5336045503&toolid=10001&customid=envirotek
(11) http://rover.ebay.com/rover/1/710-53481-19255-0/1?type=4&campid=5336045503&toolid=10001&customid=envirotek&mpre=http%3A%2F%2Fshop.ebay.co.uk%2Fmerchant%2Fepe1958
Article from REUK.co.uk:
http://www.reuk.co.uk/Envirotek-V20-VAWT-Generator.htm
Published: 12th August 2008
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