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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: pipopak on November 30, 2011, 04:51:45 PM
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I have the crazy idea that a windmill would be better than solar panels in a bus because:
1) it is cheaper and easier to maintain
2) works 24/7/365 as long as is there some breeze
3) works in any weather (within reason. Hurricanes not recommended).
4) can be made easily removable for driving
Am I right?.
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...
Am I right?.
Not really:
1) it is cheaper and easier to maintain
Solar is running about $1.75/watt right now and has no moving parts and thus zero maintenance, other than maybe keeping the panels clean. Wind turbines are running about $1.15/watt, but have lots of moving parts that need to be replaced periodically such as bearings, blades, and, eventually, the rotor and/or stator. Lifetime cost per watt is probably comparable or a little higher for wind, but it is definitely not a slam-dunk as you suggest.
2) works 24/7/365 as long as is there some breeze
Umm, no. "Some breeze" will not cut it -- you basically need winds of 10-15 kts steady to get any power from them at all, below that many won't even turn. These only work well in places where steady wind of above 10 kts is a given.
3) works in any weather (within reason. Hurricanes not recommended).
Also, no. Above 40 kts or so, they become problematic. You pretty much need to feather them once you start seeing gusts above 60 kts or so, if you can. Lots will depend on the mount you fabricate. And, as noted, below 10 kts or so, they really don't provide any power.
4) can be made easily removable for driving
Well, OK, but I would turn this around and say that an advantage of solar is that it does not need to be removed for driving, and, in fact, continues to provide charge.
On top of all this, they are noisy as all get out. I know boaters that will leave an anchorage if they see a rag-hanger with one of these monsters come in. FWIW.
If you spend several months of the year in a place where one of these will work well, they can be a real boon. For most RVers who move around more frequently than that, they are probably not a worthwhile investment.
-Sean
http://OurOdyssey.BlogSpot.com (http://OurOdyssey.BlogSpot.com)
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They make noise, and as noted, offended neighbours in some locales will forcefully remove you and/or your weedwhacker, rather than move themselves.
I'm pretty sure a BB gun would provide some entertainment pinging off chunks of the blades and watching it go all wonky as it spins off balance.
Oh, I'm sorry, is my bias showing?
happy coaching!
buswarrior
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Totally and 100% agree with Sean's answer above.
We often get asked why we don't do a wind generator in our RV setups. And that is exactly why. Solar is absolutely quiet, so passive and you really don't have to think much about it after you get it set up. No set up, no take down, no noise, no angry neighbors ... and works in many more weather conditions. And these days, the panels are pretty darn cheap in comparison.
We'll be sticking with solar when we complete our electrical system, and not even considering wind.
- Cherie
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Good!!. Asked a question and got a civilized detailed answer. Bad idea. File in the insane stuff folder. Thanks!.
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A very educational thread! Thanks, people!
Please excuse my ignorance:
Would there be a similar monetary investment in either solar panels or wind power as far as the battery bank, charger/regulator, etc?
Thanks in advance!
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(snip) Would there be a similar monetary investment in either solar panels or wind power as far as the battery bank, charger/regulator, etc?
Some details will vary but (pretty much watt per watt), yes, the investment in these "controller/storage items" will be similar.
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I vote for both....
Adding a turbine to your solar array will help you on cloudy days, & night time when the sun is unavailable!
Usually lots of wind when bad weather is blocking the sun..
Nick-
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Yes, my inclination is to say 'Both' as well, especially as they can share the same charge controller and battery bank.
Wind turbines are also something which you can theoretically build yourself, which would make the cost/benefit comparison with PVs a bit meaningless.
Jeremy
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I thought you meant a big propeller on the top of the bus to get free power as you drive down the road, connected to an alternator to run the roof AC! That is what I am going to do - as soon as the laws of physics get repealed! ;D
Brian
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(sounds from pawing through the trash looking for my discarded idea) so it is not THAT nuts, a small turbine as either a backup or complement to the panels. So I could theoretically have less or smaller panels and use the turbine when is not a P.I.T.A. for the rest of the world. I would really have to shot back to somebody with a man's size rifle (no pathetic BBs for me).
There are videos in youtube about making your own turbine, actual cost almost next to nothing. There is even a guy who made them out of discarded ceiling fan motors, posted a whole series of vids detailing the operation. Will look for them later and post the link.
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This guy up the road has been "playing". He started out with two GM 60 amp alternators with props attached, and then began buying solar panels and covering his garage. Hes got a bank of "used" car and deep cycle batteries (nothing matches), a charge controller he bought off ebay and an AC inverter I think he said was 4K watts.
He said he started with the mini wind turbines, but that by the time he had the third cell up he no longer needed the wind. He claims he can run everything he needs in the garage, lights, occasional power tools like a drill or whatever, and still watch TV all night in the house after running a dedicated circuit into the house. Thats a large 40 some inch flat screen and surround sound. Last I looked he had 6 panels (bought at harbor freight) on the one side of the garage roof, not even well situated to the suns path. He thought that if he could cover the rest of the one side of the garage roof, he wouldnt need metered service anymore.
It all looks pretty Rube Golberg, but its working and he does not have much invested, he said maybe a years worth of electric bills.
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Quite some time ago, I saw presentation on vertical shaft windmills (think "cup" type water wheel mounted horizontally). The thesis was they could be mounted on the roof of a building (small vertical footprint), would not have a prop that was detrimental to birds and was quieter.
I did a bit of a search this morning and the following site seems to be objective:
http://www.exege.com/vertical-axis-windmills (http://www.exege.com/vertical-axis-windmills)
Looks like it is a compromised system, but might have some application in RVs
Jim
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I vote for solar panels, and then (if off the power pole) just run the generator. You can (and should) make the generator to be just about silent running (think movie studio on site generators) so not to disturb your neighbors. A bladed wind turbine would take many hours (if not all day) to charge up the batteries-of which the generator could do a big bulk of in just 2 hours. Good Luck, TomC
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A bladed wind turbine would take many hours (if not all day) to charge up the batteries-of which the generator could do a big bulk of in just 2 hours. Good Luck, TomC
A wind-turbine of the size we're talking about would take weeks to fully charge a set of bus house batteries. Let's not kid ourselves that either solar or wind is ever going to replace a diesel generator or shore-power - unless perhaps you have a very expensive alternative-power set-up, and are living very frugally in an area with ideal sun/wind conditions.
In reality, all solar panels or a boat / RV-type wind turbine will do is make life a little easier by, for example, giving the batteries a small but useful continuous float-charge to keep them topped off when the bus isn't being used.
On the subject of vertical axis turbines - this is the type I will build myself when I finally get around to it, because the area where I would mount it has very disturbed wind. But be aware that vertical-axis turbine are inherently much less efficient than the conventional type because, aerodynamically-speaking, they work only by drag, not lift:- in simple terms, a horizontal-axis turbine will spin far faster than the speed of the wind, which a vertical-axis turbine cannot do.
Jeremy
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I have solar panels and a 400 watt quiet wind generator.
The wind generator only puts out only an amp or two (on the beach) with surges up to maybe 15 amps. This would be fine for a trickle charge if I only had a 100 amp battery but I have 1600 amps so for me it is useless.
Contrary to popular opinion solar panels will provide you with (if you live in the sun) all the necessary electricity to live a normal life in your bus.
I have 1580 watts to charge 1600 amps (1000 lbs.) of batteries.
We have :
Electric Fridge
two exhaust fantastic fans on most all day
coffee maker
two computers/TV 4 or 5 hours a day
100 watt stereo
two ham radios
washing machine
toaster
bread machine
all my electrical saws, grinders and tools
etc. etc.
So far almost all the work done on the bus has been with the power provided by it. Almost everything we have is 120 volts.
We have a 2000 watt inverter generator we did run a few times last winter to run our 120 amp charger while in the southwest.
Right now I'm in a spot in southern Mexico, I have sun from 11:00 am to 4:00 PM, the batteries are down to 85% at 11 and up to 100% about 2:30 or 3:00.
You cannot have a wind generator on a mobile rig that puts out enough power to do any good because they are tooo heavy to lift up and down.
Solar panels work and with the right setup are fully automatic with no moving parts.
Just my educated opinion
Jerry
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Jerry, I'm just wondering what size inverter do you use?
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Jerry:
I just sent you a personal message.
73,
XE1UFO
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Since we did a bit of boondocking this past year, I have looked into ways to charge without running the generator strictly for that purpose. A couple of solar panels would be maintenance-free, be permanently mounted out of the way, and would help cut down on run time. I also considered carrying a small, very quiet generator just for charging so I could run it without feeling I was bothering the neighbors. I would not consider the wind generator since it would require set up and storage space for a relatively undependable, small production. Where would you put it? If on the ground, some kid, dog, or childlike adult might cause a problem. If you want it on the roof, installation and removal could get to be a real nuisance. You would definitely need to add some permanent mounts that could take heavy gusts. Either way, if a storm comes up in the middle of the night, you will have to decide if you should get out of bed to stow the equipment or allow God to take care of it.
When I had an awning, I would often close it if I were going away for a couple of hours since a surprise storm could do a lot of damage. You would have to consider this with your turbine also. If you leave it on the ground, you will also have to consider whether someone might steal it when you go out to see the sites. Will you want to take it down and put it up again later?
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Short of a very large prop, your not going to generate much power with wind electric. A Jacobs with a 26 foot prop is rated at 530 KW. If you cut the prop in half, youll get about 25% so about 130 KW. Thats really not going to run much, and a 13 foot prop would be huge to be taking down and putting away in your Bus, and it really needs to be high up in the air to catch the wind... Its really something made to be permanently mounted.
And that 530KW is max rated output, you might be lucky to see half that depending on the area and terrain.
Anyway, to do it right there should be a governor that starts feathering the prop it out of the wind after it reaches peak rpm, and there should be a high speed brake to stop it once its fully feathered. There was one out by us that came unglued in high winds, it threw a blade many hundreds of feet. Try that at a campground.
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... about 130 KW. Thats really not going to run much, ...
Wow, 130 kW is ten times the size of most RV generators. I know if I turn everything in my bus on at once it's less than 10 kW.
Most RV or boat-size wind turbines are in the 4'-6' diameter range, with ratings in the neighborhood of a kilowatt.
FWIW, without air conditioning, we use about 4kWh per day of electricity. If we wanted to go 100% solar, like Jerry, we'd need about 1,200-1,400 watts of panels (we only had room for 330 watts). If we were someplace where the wind was pretty constant, we could probably get by with a 1 kW turbine.
I still don't care for the amount of maintenance, setup/teardown, and noise involved with wind turbines. They are a better choice for a fixed structure, where these issues are easier to address, or a boat, where completely unshaded flat mounting surfaces are scarce and vessels are further apart in anchorages.
-Sean
http://OurOdyssey.BlogSpot.com (http://OurOdyssey.BlogSpot.com)
(Update: realized I typed radii but wrote diameter. Fixed the numbers to match.)
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Jerry, I'm just wondering what size inverter do you use?
3000 watt ProSine
2 MX60 Outback Charge Controllers
Jerry
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Keep in mind too that the taller the windmill, the more power it produces. General rule of thumb is that the wind speed at 30 ft. above the ground is twice as strong as at ground level. Also any obstructions, ( houses, trees, hills, fences, etc.), within a couple of hundred feet causes turbulence in the air flow which affects performance. If you look closely at windfarms you will notice that sometimes there are big gaps between rows or between individual towers. This is because they do site surveys to determine precisely where each tower goes to take advantage of the maximum amount of air flow for the maximum amount of time. Lot of money involved with these things, they don't just throw them up anywhere that they feel like it.
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I have 1580 watts to charge 1600 amps (1000 lbs.) of batteries.
I would absolutely love to see pictures of how your solar panels are laid out... we would love to put that much on our bus! :) That's totally sweet. We currently have a 500 aH lithium ion battery bank that we'll probably expand up to 1000 aH soon, that will give us similar capacity of your 1600 aH, but in under 300 lbs.
Our next major electrical project is solar, but not seeing how we can get more than about 700-900 watts on our 4106's curved roof. (If we could figure out how to fit mini-split A/Cs and get rid of our roof A/Cs, that would help.)
As far as living off solar... for the first year of our full time RVing, we both thrived with a single 110 watt panel and 280 aH of battery storage. Enough for our computers, internet and lights (we had a 16' trailer at the time). Then our 17' trailer (3 yrs of full time travel) we had 200 watts with 230 aH of AGM batteries that was a great balance for us. Looking forward to adding solar to our bus and getting back to being more self-sufficient.
- Cherie
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This is the kind of windmill I have in mind:
http://www.google.com/products/catalog?client=ubuntu&channel=fs&q=windmill+electric+generators&oe=utf-8&um=1&ie=UTF-8&tbm=shop&cid=4369387138458642610&sa=X&ei=uoPZTpqLAs7HsQKK3M2WDg&ved=0CIoBEPMCMA (http://www.google.com/products/catalog?client=ubuntu&channel=fs&q=windmill+electric+generators&oe=utf-8&um=1&ie=UTF-8&tbm=shop&cid=4369387138458642610&sa=X&ei=uoPZTpqLAs7HsQKK3M2WDg&ved=0CIoBEPMCMA)
or this:
http://www.google.com/products/catalog?client=ubuntu&channel=fs&q=windmill+electric+generators&oe=utf-8&um=1&ie=UTF-8&tbm=shop&cid=10632941392377206689&sa=X&ei=vITZTrfhDee1sQLKgd3WDQ&ved=0CIgBEPMCMAE (http://www.google.com/products/catalog?client=ubuntu&channel=fs&q=windmill+electric+generators&oe=utf-8&um=1&ie=UTF-8&tbm=shop&cid=10632941392377206689&sa=X&ei=vITZTrfhDee1sQLKgd3WDQ&ved=0CIgBEPMCMAE)
Mounted on top of a post up front, easily removable when needed.
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Wow, 130 kW is ten times the size of most RV generators. I know if I turn everything in my bus on at once it's less than 10 kW.
Oops that was a typo. Actual output on the 26 foot prop model is rated at 15 KW at 26 mph wind speed. So halving the diameter would drop it to about one fourth, about 3.5 KW.
The 26 footer is only about $70,000 with an 80 foot tower.
Some folks we knew back in Minnesota had four of them in their family. I asked the kid about them, he said they would likely never pay for themselves in his lifetime. The maintenance alone was much more than anyone in the family paid in a years worth of electric bills.
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I have 1580 watts to charge 1600 amps (1000 lbs.) of batteries.
I would absolutely love to see pictures of how your solar panels are laid out...
Cherie:
http://crowncoach.clanteam.com/ (http://crowncoach.clanteam.com/)
I also intend to have a useful amount of PV panels on my roof, ideally at least as much as Jerry, or even more (my Crown is 5 ft longer than his). Jerry tilts his entire panels, which is probably the best way. I may do that, or I may do it slightly differently - I'm thinking of a 12"-wide diamond-plate walkway along the center of the roof from my front roof hatch to the rear one, and hinge my panels to this walkway. This way half the panels can be raised as high as needed, and the other half will lay down against the curved roof, and this will catch the sun almost as well as on Jerry's bus and a lot better than simply having them permanently flat. Your 4106's roof is curved about as much as Crowns like Jerry's and mine. Another incidental benefit to covering almost the entire roof with panels is keeping the bus cooler - as long as air can circulate under the panels (which helps their efficiency) there will be much less solar energy heating the roof and hence the interior. This changes the amount of interior cooling needed, maybe to the point that simple evaporative coolers could suffice - their power draw may well be within the ability of a roof-full of PV and a good-size battery bank. Just a thought.
PV is still dropping in price. Pallets of cosmetically-blemished panels can be had for little over $1 per watt *, so 2000W or more of PV is a viable option, especially that I really don't want to run a generator except in emergencies. After the initial expense it should be essentially free electricity generation for the next two decades or so! Being able to keep your batteries always well-charged should also prolong their life, making five years or more from a set of cheap golf-cart batteries a reasonable expectation. Whatever happens to diesel prices in the short-term is up in the air, but I think it's safe to assume the long-term prognosis for diesel prices will be steadily upwards, making PV more attractive as the years go by.
Jerry and his bus are my inspirations. Jerry, you are very lucky to be able to do what you do!
John, more than slightly envious
* for example - http://www.sunelec.com/solar-panels-c-5.html (http://www.sunelec.com/solar-panels-c-5.html)
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Thanks to all for your information!
In case you guys missed it, this guy has some awesome info on full-time boondocking on 100% solar power!
http://handybobsolar.wordpress.com/the-rv-battery-charging-puzzle-2/ (http://handybobsolar.wordpress.com/the-rv-battery-charging-puzzle-2/)
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Yeah! Now that's excellent information. That's what I want to read - real-world experience, not just theoretical reasons why it shouldn't work. It gives me renewed optimism that I'm on the right track thinking I can live almost entirely off solar. When you add in other energy savings, such as using "fridgers" * (my description) instead of power-sapping conventional fridges, there's no reason it shouldn't work. You just have to be imaginative and resourceful.
* - http://www.mtbest.net/chest_fridge.html (http://www.mtbest.net/chest_fridge.html)
John
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Just thought I'd update this thread with a couple of wind turbine photos taken from today's BBC news here. These are two different turbines that suffered in some strong winds we had yesterday:
(http://news.bbcimg.co.uk/media/images/57224000/jpg/_57224051_fireturbine.jpg)
(http://news.bbcimg.co.uk/media/images/57213000/jpg/_57213871_wind_turbine_billy_muir.jpg)
Jeremy
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Did the top turbine's blades not feather correctly? I heard that wind gusts reached 165 MPH - at that speed I'm surprised more turbines didn't fail. I wonder what provision smaller home-type turbines have to deal with high wind speeds. Do they have a brake, or do their blades feather, or what?
John
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Yes, it's got to be a blade feathering problem - in fact you can see in the photo that the whole turbine head is actually facing the opposite direction to it's two neighbours.
The vast majority, and by far the biggest, of the UK's turbines are actually offshore. Goodness knows what havoc they'll find when the wind farm service boats can put to sea again.
Jeremy
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Not sure about all, but jacobs feather out of the wind after max rpm is reached, about 45 IIRC, becoming fully feathered up around 90 IIRC, at which point a brake is engaged to stop it.