In our last posting we talked about RV batteries for storage, and how to produce power from the sun. Let's see how you can get free electrical power from the winds.
Power from the Wind
Priced on a "per watt" basis, wind turbines beat solar panels hands-down. A typical RVer's wind turbine costing in the mid $500 range can put out 400 watts of power in a 28 mile-per-hour wind. You'd be hard pressed to spend much less than $1500 to obtain solar panels that will produce that much power. But hang on, there are plenty of considerations besides dollar costs.
For best results, you'll need consistent winds to make your wind generator practical. Think along the coasts, in the Plains states, and on the deserts. Wind and solar is an excellent combination, as usually when one isn't working, the other one will.
So what do you look for when shopping the wind power market? Since the wind has so much "muscle," you need to keep the size down. The greater the power production, the greater the torque exerted by the wind on your system. If your wind generator tower is mounted on your RV, it could cause real problems if not securely mounted.
|R&T DeMaris photo
Many RVers find the "Air-X" line from Southwest Wind Power to be a good starting point. Rated at 400 watts in a 28 mile per hour wind, they're small enough to easily handle, yet large enough to produce a useful amount of juice. Ratings are a sneaky thing though, because not all manufacturers use the same standard--some may measure their output at a different wind speed, making comparisons difficult. Here's the math:
As wind speed doubles, power output increases eight times. For example, if a wind machine produces 50 watts at 14 miles per hour, it will produce 800 watts in a 28 mile per hour wind. But the converse should be considered! As wind speed is cut in half, power output is reduced to an eighth.
One thing to look for is the "peak output" power figure--that tells you how much power the machine will produce just before it "cuts out" or goes "into regulation" to protect itself from wind speeds that are too high for its design. Really, a good measure where most everything else is equal is "swept area" which describes just how much "wind catching" area the blades cover. The greater the swept area, the greater the power output.
Make sure the wind machine you buy is compatible with your RV's electrical system. If you're a "bus nut," and 24 volts is your standard, make sure the turbine can be set to produce that output. Also find out how the machine is regulated--some "turn off" the alternator (which produces the power) at a given wind speed, some mechanically change blade position. In others, the blades actually twist in the wind, scuffing off excess wind power. The latter can be a bit noisy in high winds. Can you "turn off" the wind turbine? A switch allows some to do this, and that's handy if you need to "pack up" and head out on the road. Trying to deal with a wind-spinning turbine without shutting it off is to risk your life.
How much will the wind turbine weigh? It's important to know, as you'll need to come up with a tower or mast to mount it on. The higher above the ground the turbine is mounted, the more power you'll get out of your machine. Our "tower" system allows us to run our turbine about 10' above our RV roof.
Some folks mount their wind "genny" on their rigs, others mount them on the ground and use guy wires for support. Thick walled electrical conduit is a popular "tower" material, while others have fancy steel tube setups. Whatever you do, DO NOT DISREGARD the generator manufacturer's specifications for tower design. The whole matter of mounting a wind generator is probably the hardest part. At this point, there's no good commercially produced tower system available that really lends itself to RV use.
The electrical end of the matter is usually straight-forward. Most wind machines have "built in" power regulators; you simply need to observe polarity and use appropriately sized wiring. Don't try to short-change in this area, as wind turbines produce a large amount of power, and undersized wire will not only reduce the amount of usable power, it can actually get hot enough to start fires.
Depending on your boondocking lifestyle, power from the wind may be just what you need to keep your batteries charged up, and your electronics humming.
For more information on boondocking power, both wind and solar, check out our book, RV Boondocking Basics, available on rvbookstore.com.
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