Steve:
Please then consider a system with a wind generator and a battery backup. If you used a set of four 12V @ 7AH batteries wired in series you can see a total power capacity of 336 WattHours. (Note that this type of battery is commonly available and you should be able to expect over 2 years of operational life). If one assumes a conservative 50% system effency then this could power the 3 Watt load for:

(336*0.5)/3=56 hours.

So given that you have lots of wind I expect this should work quite nicely. (Note if you expect that wind is not so predictable as being available at least every 2 days then then you simply need to increase the battery capacity accordingly. Note that 12V 14AH batteries of sealed technology is also readily available).

Ready made wind generators are definately the way to go. It would be silly, in my book, to design a custom built one. Here for example is a link to a Air/Marine Wind Generator that produces raw 48V at peak 400 watts listed at $845 US.

Here is a link to more information about these pole mounted wind generators such as the AIR403.

The idea is to size your battery bank (and you could even use automotive batteries but they may not be as maintenance free as sealed technology) to sustain the system for the longest wind free periods that you expect to survive. Then you select a wind generator that can fully recharge the batteries when the wind becomes available.

Michael Karas