RV wind turbine??

[Mike Jordan]

Is anyone using an RV wind turbine that is small enough to be easily portable and put up and take down, but effective enough to supply 100-300w?

 

[pollenface]

I have a Chinese 400w one on my shed. It makes about 10wh a month.

 

[chrisski]

I looked at this last year and found nothing I would want to spend my money on to put something together. I also decided that I was not the first person to ever think of that and if it was a good idea, there’d already be a good YouTUbe video.

The blades would be at least three feet long. At this point, mounted on the roof, this would probably tear the roof off the RV if the mount did not give first. I looked at truck hitch poles to mount the truck hitch. The truck hitch mount may still be ion E-Bay.

The 400 watt Chinese windmills had terrible reviews and seem to get rebranded and have a different sticker put on it that got the same result. I decided if I got one, it would be an Air Primus.

I think I could have put something together for around $2k.

My goal was only 150 - 250 wh of power a day. The places I was staying had very strong morning or evening winds. Rocking the RV strong. That would be enough to produce power for about 45 minutes to 2 hours a day. Basically to last the night with a little pushed back into the battery for less for the sun to charge the next day.

That ended up being a lot of work for 10 to 20 ah of power a day. I took a good look at what people were actually producing with wind. It’s hard to find that data because most people give up wind produces so little power. If I did not get the winds that rocked the trailer, I don’t think the turbine would produce the tiny amount of power I set as a goal.

Another reason I paused this project was something like that would attract people as far as the eye could see and I’d be afraid of someone touching something or walking onto the turbines.

Other places that are ideal for windmills could have better results.

 

[Mike Jordan]

I looked at this last year and found nothing I would want to spend my money on to put something together. I also decided that I was not the first person to ever think of that and if it was a good idea, there’d already be a good YouTUbe video.

The blades would be at least three feet long. At this point, mounted on the roof, this would probably tear the roof off the RV if the mount did not give first. I looked at truck hitch poles to mount the truck hitch. The truck hitch mount may still be ion E-Bay.

The 400 watt Chinese windmills had terrible reviews and seem to get rebranded and have a different sticker put on it that got the same result. I decided if I got one, it would be an Air Primus.

I think I could have put something together for around $2k.

My goal was only 150 - 250 wh of power a day. The places I was staying had very strong morning or evening winds. Rocking the RV strong. That would be enough to produce power for about 45 minutes to 2 hours a day. Basically to last the night with a little pushed back into the battery for less for the sun to charge the next day.

That ended up being a lot of work for 10 to 20 ah of power a day. I took a good look at what people were actually producing with wind. It’s hard to find that data because most people give up wind produces so little power. If I did not get the winds that rocked the trailer, I don’t think the turbine would produce the tiny amount of power I set as a goal.

Another reason I paused this project was something like that would attract people as far as the eye could see and I’d be afraid of someone touching something or walking onto the turbines.

Other places that are ideal for windmills could have better results.

Trying to do some research myself. I do not think the standard airplane prop horizontal wind mill would be practical. The vertical axis turbines don't seam to be as efficient, but would be a better form factor for an RV. I only found one guy doing it. So like you I am starting to think it is not terribly practical But thought I would ask while I search some more

 

[chrisski]

So like you I am starting to think it is not terribly practical But thought I would ask while I search some more

If you make this work or try to build it, please start a thread so we can follow you. I want you to succeed at this.

 

[Zoomyn]

A few insights - Betz Law states a perfect capture of wind to mechanical spin can be at best 59.3% - and if we get 20% we're lucky... so....

121.3 watts possible from 3.0 ft dia prop (7.1 sq ft) in 15 mph wind...

OR: 215.6 watts possible from 4.0 ft dia prop (12.6 sq ft) in 15 mph wind...

Now apply Betz - 20% extracted...

And generator efficiency.. off another 20%

So at 15 mph windspeed a three-foot blade nets ~20 watts and a four-foot set nets ~35 watts, five-foot set nets ~54 watts, six-foot set nets ~78 watts, seven-foot set nets ~106 watts, eight-foot set nets 138 watts...

okay - a run-away turbine overspeeding is a fearsome beast - when blade tps spin past the speed of sound they generate sonic booms, not something to stand next to.

So the windmill needs to always have a load on it - if your batteries get over 90-something percent charged the current drops and the turbine will runaway,, and emergency shut down absolutely has to work -

the sexy looking storebought 39-inch turbines usually are designed so the blades flutter on overspeed - and sound like roaring engines without mufflers - not something to let run while you are away, ask the sailboat community...

 

[Zoomyn]

Anyhow - what was unsaid is there is no free lunch - and you would not catch me sleeping under a turbine blade set large enough to generate real power : )