UK-based Marlec Engineering have been producing wind turbines for decades, and the Rutland series are perhaps the best-selling small turbines in the world. Both their 913 model, which uses marine-grade components and is optimised for use on yachts, and their furling 910 and 1803 models, recommended for land-based applications, are available in 24 volt versions. If it's a 12 volt Rutland you're interested in, try our parent company, Midsummer Energy. These turbines are great value for money, and are very reliable.