When I started out five years ago selecting modifications for my Roadtrek to support a full-timing, boondocking lifestyle, one thing I looked into was a portable wind turbine. Like solar panels, these allow you to generate electricity without burning fuel, so they're great for RVers, or so my reasoning went. The challenge was to design a mast to get the wind turbine high enough to generate power, yet lightweight and portable enough to pack up and carry with you.
Scouring the internet, I found a mast base you could run over with your rear tire, with a hinged socket to put the mast in while the mast was lying on the ground, and then you pivot the whole thing vertically. However, these were no longer for sale, so I was forced to steal this idea, make some modifications, and get one welded up. Instead of a mast support three feet up or so attached to this base, I used a support that would attach to the Roadtrek, with suitable rubber bushings to prevent transfer of vibrations to the body.
Since I wasn't going to be able to carry a 20 foot mast in one piece, I made a mast with four foot sections of aluminum pipe, with a slightly larger size pipe sleeved over it to join the sections. A throughbolt at each junction, and I had something sturdy enough to stand up to strong winds, but still light and portable and easy on the GVWR – the total weight I could carry with my chassis.
For a wind turbine, I bought an Air-X built by Sunforce. Nominal power is 400 watts – they now have two 600 watt models they sell. These models have integrated circuitry which regulates the output to prevent overcharging, as well as circuitry to prevent over-revving in high winds. Since the body is just a fancy permanent magnet alternator, putting the magnetic windings slightly out of phase will slow down the rotational speed if the wind is too strong, avoiding the annoying fluttering noise earlier designs made when they compensated for excessive wind speed. With this circuitry, the wind turbine can be wired straight to the battery bank, which I did by making a wiring harness which went down the interior of the mast to a quick-connect on the Roadtrek body near the mast base.
Off I went with my fancy new wind turbine, looking for good wind conditions. That's where the trouble started. Power increases as the square of the wind speed – it's the old F = MV^2 equation from Physics 101. The rated 400 watts would show up all right – in a steady 28 mph wind – not exactly ideal camping conditions. At half the optimal wind speed, you only get a quarter of the rated power – 100 watts. Other than a nice steady wind off the Gulf down at Padre Island National Seashore, I never found conditions where the wind turbine would keep up with the 200 watt demand of my normal usage pattern (TV, internet, and laptops, plus some lights).
Most of the time power production at inland locations was in fits and starts as the wind picked up and dropped off, or changed direction. My mast was only 20 feet high – permanent mountings are usually at least double that to get clean air flow without interference from the surface. I just couldn't design a tower that high which would be sturdy and still collapse into storable and transportable pieces, so I almost never got clean air flow.
A final consideration was the carbon fiber blades, which were marvels of engineering. However, I had to take them off the hub every time I used it to get it down to a storable size, and it's an exacting process of torquing the fasteners. Carbon fiber is very strong but it needs careful handling to avoid damaging it. The blade tips are barely subsonic at maximum power output, and structural failure will send sharp pieces flying into nearby objects, like my solar panels for instance. Or maybe me. There's a reason you see wind turbines mounted out in a field far away from residences, and the mounting I designed wasn't able to utilize this common-sense precaution because it used the Roadtrek weight and structure to stabilize the mast.
Compared to my solar panels, the wind turbine was a lot of work. It only took thirty minutes or so to set up, but since the mast was attached to the Roadtrek body it would have to be lowered and disassembled every time I had to drive somewhere for water or groceries, so it never stayed up for more than a few days at a time. In contrast, the solar panels were always there and in position – all I had to do was park in the sun. No work necessary.
I carried the wind turbine around for a year and a half, using it on maybe a half dozen occasion, and then stored it when I decided that it just wasn't worth the weight and space it took up in my limited onboard storage capacity. Maybe someday I'll settle down in a mountain pass or on the ocean and can mount it where it will do some good, but my conclusion is that solar is the way to go for RVs, not wind power.
Comments are closed.