Portable 12 Volt 17 Watt Wind Generator with Automatic Furling

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Picture of Portable 12 Volt 17 Watt Wind Generator with Automatic Furling
Parabolic Nose - Side Profile - closeup view.JPG
Grainger Shaft Arbor.jpg
Parabolic Nose - Side Profile.JPG
I've just designed and built a practical, portable 12 Volt 17 Watt wind generator that is ideal (and appropriate) for setting up in campgrounds, parks, Earth Day exhibitions, research stations, and third world homesteads.

On "light breeze" days (5mph = 2.2m/s) when most wind generators are becalmed, this light-and-nimble unit reliably generates power, at charging levels, fully taking advantage of the erratic, gusting winds that are so common in near-ground conditions.

A 48VDC, 1,600 rpm brushed permanent magnet motor (#370-350-00 / PE24113G -from a medical centrifuge), with a standard keyed 5/16 inch diameter steel shaft, was used to serve as the generator. A shaft arbor, 3/8-24 right hand (Grainger Item# 3ZN05 / Dayton Item# 3ZN05) was fitted on the shaft, to use as a 12 Volt generator, @ 550 rpm, when turned clockwise. The motor, weighing in at just under 3 pounds, has permanently lubricated bearings, but is not weatherproof.

Note: If you plan to use a counter-clockwise set of blades, the timing of the "generator" brushes (2 carbon brushes) and internal commutator is such that the same amount of power (Amps and Volts) is also generated when turned counter-clockwise, but be aware that the shaft arbor manufacturer's suggestion as to "right-hand" and left-hand" thread pertains to motors only, and not wind generators, where the just the opposite thread is required.

Note that the Grainger Shaft Arbor requires a thin, soft metal shim inserted against the flat face of the standard keyed generator shaft, for the allen set screw (which has a knurled cup point) to bite into and firmly hold the arbor in place. I used 2 layers, fashioned from an aluminum beer can. Or, use a replacement allen set screw with a soft brass core. Also, two, 1-1/4" thin neoprene washers are needed to pad (and grip) the 1-1/4" steel washers that come with the shaft arbor. The original shaft arbor nut was also replaced, with a nut with a thicker profile, with a nylon locking core.

This portable wind generator is ideally suited for one 12 Volt, 21 Amp Hour sealed lead acid battery.

Granted, that's not much power, when compared to typical permanent, stationary wind generators. But this lean-and-mean device was designed to fill in the void, to reliably provide 12VDC power to remote, inaccessible locations.
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mikey515 years ago
I don't understand how the furling device works.  When the wind picks up, what makes it pivot out of alignment with the wind?
The motor is off-center, and mounted on a hinge on-centre, so strong winds will push the blades sideways, which reduces the surface are into the wind. If you google "windmill furling explained" there is a good explanation on the-back-shed web page.
Andsetinn1 year ago
This is nice. A slightly more information on the build itself would be nice but the furling and bladesize info is worth a lot. I look forward to more instructables. :)
jdole12 years ago
Thanks for posting this - I've looked everywhere for furling devices for homebrew / DIY wind, but the only thing I found was a $350 tail vane kit over at WindyNation!

If you feel like it, I bet you could sell furling tail vane kits (various sizes.)
sony flores3 years ago
please send me instructions and steps through my email:

Thanks a lot,looking forward for your favorable responds..
sony flores3 years ago
I just want to ask the electrical connection from generator to battery charger then to the battery to supplied appliances.

do i need battery charger or i can directly connect to the appliances.

i want to build portable windmill,can suggest me in order realize my plan without any expenses.?

i want 12V or any suitable for light bulbs only that can able to supply my house lightings.
jetboy3 years ago
where did you purchase the motor at
Harry3Lime3 years ago
How far from the pole are the anchors placed?

At what heights are the guy wires attached?
shastalore (author)  Harry3Lime3 years ago
The distance is already stated the instructable, but is always dependent on the height of the mast, so I'd rather not state an exact number here.

But a good rule of thumb is to place the upper guy wire hook-up as high on the mast as possible.

And for the distance for each of the four anchor stakes from the base of the mast, the guy ropes should be at a 45 degree angle, both from the ground, and the upper guy wire hookup.

But if you're setting up on sand -or on solid ground but with high winds, then 30 degree / 60 degree angles will provide better stability for your rig (30 degree angle from the ground / 60 degree from the upper guy rope hookup).

And for a mast taller than 10 feet, especially a slender, flexible mast, you will need to add a lower guy wire hookup, about one-third to halfway down the mast, and anchor those lower ropes to the same four anchor stakes. The exact positioning of the lower guy wire hookup is best fine-tuned during high winds, carefully observing what position provides the best bracing and rigidity of the mast.

And don't hesitate to add yet a third guy wire hookup, if you're really ambitious and building yet a taller mast than my 15 foot version.
ddavis6623 years ago
Cool idea!
Looks great aestethic wise and it is a Great product im thinking of making a miniture version !
shastalore (author)  stephenniall5 years ago
Go ahead and build it. Looking back, I designed on the side of caution, and made it a little too heavy and sturdy. You could actually build this wind generator much lighter -and use the same generator. I may also do just that, and mount a new generator, with 50% more power, on my existing wooden rig. As for the over-all design, I tried to give the wind generator a pleasing profile, with classic lines. A habit I developed early in life, with balsa model airplanes, with a zero-tolerance for weight.
So How do I buy One *** ??? Miles Of Smiles Sundialing
Would it be practical at all to construct most of the fins and possibly some of the blades of this style generator out of Lexan or some other acrylic sheet? Nascar uses Lexan for their windshields so it should hold up in this use well enough. UV may be an issue, but there is also UV protected Lexan. Using the Lexan would fairly-well make the blades and fins disappear or at least blend into the background better and possibly be less obtrusive. Just my $.02 DC
Lexan/polycarbonate, yes. Acrylic, no. While acrylic looks like polycarbonate (Lexan), they are very different. Acrylic will break and shatter very easily; it doesn't have the strength. Polycarbonate does. I would be wary of invisible blades being dangerous.
shastalore (author)  DieCastoms5 years ago
Sure, it could be designed, with Lexan, to function well. Just don't design the blades to be invisible, for safety reasons -at least for a portable wind generator. I've noticed that hobbyists and tinkerers tend to plan and build their projects with the most expedient means and materials at their disposal. For example, I was quite intrigued by a post about a wind generator that a hobbyist had put together: It was fairly easy for him to sand-cast an aluminum mount for his generator and quickly machine it down, to snugly fit and bolt into place! What someone on REALLY needs to do is re-design my generator, with graphite composite frame for the vane/fin, with a nylon fabric tightly stretched over it. The weight of the generator and blades are pretty much set. But the over-all weight of the portable, furling generator could then be cut 30%.
Abovethesky4 years ago
I have 12volt stepper motor it generates 103volt ac how I recharge my 12volt batteries.
ChibiButo4 years ago
 awesome try going smaller for like a altoides pack 
timbaker1725 years ago
Wow! Thanks for showing those detailed pics of the furling system. I have been trying to find a simple way to make a furling system for a week now. For some reason a spring loaded hinge did not occur to me. I have already built a small turbine that charges NiCd AAs and I'm working on a bigger one. My next step is to try this hinge idea on the little turbine first.  Thanks again.
batonas5 years ago
you would get more power if you use a gear box or a sheaves
shastalore (author)  batonas5 years ago
I initially considered a gear-up, with my first set of orthodox, but crudely made PVC blades.

But I wasn't wild about the idea of the energy loss in the transfer, not to mention the additional weight, complexity, and maintenance issues that are inherent with going in that direction.

You may have noticed that my devices appear, at first glance, quite simple and obvious.  But I prefer to put a lot of sweat, research, and field testing into these things, and generally feel that the end product is worth the time and effort.  But none of my projects are never really finished, as I sometimes tend to re-visit them a year or two later and the compulsive tampering process begins anew.    
ANDY!5 years ago
SWEET. Is there any way of building the blades for real cheap cause I don't want to buy one. 5 out of 5!
snotty ANDY!5 years ago
Yes! I just figured out how to make bamboo wind turbine blades. They are very easy to make, they perform well and unlike PVC they won't kill you with liver cancer; so I think they are pretty nice.
shastalore (author)  ANDY!5 years ago
There may be a way to quickly and cheaply scratch build a set of high performance blades, matched to the generator, but this subject, in itself, would be an involved and time consuming research project, but an excellent post for, for someone to attempt. But I simply determined that I just don't have the time to go in that direction. I simply bought a set of 3 Air-X matched blades, for $ 100.00. They appealed to me because they were off-the-shelf, and, luckily, had the tried-and-proven performance characteristics I really needed. Another advantage is that I could quickly buy some more of the same blades, if one of mine became damaged. And after I received them, I seriously doubt that I could easily build a set of blades, this well designed. Really, some of these manufactured blades are amazing. The Air-X blades, for example, have a slight swept-forward cant, from hub-to-tip (my sketchy plans called for more). And they're extremely stiff and rigid, with an airfoil cross-section (my rough plans had a thicker cross-section). And they would have easily out-performed my scratch built blades. To build these from a PVC pipe, or wood, or fiberglass, could be false economy, as the blades are just as important as the generator. And many of the homemade blade designs on the internet are poorly thought out, and there's rarely any information provided as to how much power is generated for given wind speeds, or how many rpm's are generated by those winds. "5 out of 5"? Thanks! (somebody tell my wife that)
How should I cut PVC?
shastalore (author)  ANDY!5 years ago
There are numerous plans and cutting methods on the internet as to how to do this, but they tend to be be sketchy and incomplete. But if I were to build a blade from PVC pipes, I would only do a 2-blade design. 3-blade and 4-blade designs tend to falter when they attach to a simple flat disk hub, where the curve of the blades is distorted by the mounting bolts, creating unacceptable drag and a critical loss of performance and rigidity. A 2-blade design, made from one length of PVC pipe, eliminates the need for a separate disk hub and runs much cleaner, from an aerodynamic standpoint, as the blades angles are, simply, correct. First, draw a straight line down the length of a 4 foot length of PVC pipe, 6" inside diameter, 3/32" wall thickness. At the middle of the PVC pipe, carefully mark the point, which you will later drill out for the generator shaft arbor. This line will be the the trailing edge, of both ends of the finished blades. At each end of the PVC pipe, mark a 1 inch width. This will be the width of the tips of the finished blades, as well as the leading edge of the finished blades. 2 inches from the center point (arbor shaft) of your original straight line, and at a right angle to your original straight line, draw a 5.3125 inch arc along the outside of the PVC pipe. This will be the leading edge width of your finished blade. Repeat the process for the other side of the center point, but reversed. Using a flexible ruler as a "straight" edge, draw a straight line from the 5.3125" leading edge point to the 1" leading edge piont at the end of the PVC pipe. Repeat the process for the other end of the pipe, but reversed. This will be the leading edge of the finished blade. Using the same flexible ruler, connect the unmarked areas at the hub with a diagonal line, spanning the 4" area covering both sides of the center point, running from the 5.3125" width mark to 2" mark on your original straight line. Repeat the process for the other side of the center point, but reversed. This layout should produce a blade that will spin faster than most PVC blade designs, will provide more low-end torque, and will produce less high rpm drag. To cut out PVC blades, I use a Dremel, fitted with a small cutting wheel, and simply and quickly do a freehand outline cut. The edges are then quickly, and accurately, dressed out with a rough file or rasp. The back (leeward) side of the blades then need to be beveled, to improve the aerodynamics. But leave the outline of the concave (front) side of the blades absolutely sharp, holding to your orignally drawn dimension lines. To mount the 2-blade piece on the shaft arbor, you'll need to reinforce both sides of the blade "hub" with a front piece, and back piece, from the same PVC pipe, cut with an outline to match the hub of the blade. Glue and clamp. When dry, carefully file down both sides (concave front & convex back) of the "hub" until they're absolutely flat. If you have a drill press, this is easier, in that it can be, slowly and carefully, done with a wood boring bit, the same diameter as the shaft arbor washers, as a light "touch-bore". Next, drill out the hole for the shaft arbor. The glued "hub" must cure for at least 24 hours before testing the blade in the wind. Be advised that PVC blades should only be used on a generator (not the one I used) that turns at no more than about 350 rpm. Also, strong winds can bend the blades back enough to actually strike the mast. Also, cold weather can make the blades brittle and crack.
Dr.Bill ANDY!5 years ago
some of the other wind generator instructables have plans for PVC blades
Do you have any suggestions for places or devices from where a suitable charge controller may be salvaged? Love the project. Very well done.
shastalore (author)  balexander875 years ago
You'll probably be better off just buying one of the new electronic charge controllers on the market, as they're becoming more economical, and portable, every year. But check out ebay and see what you come up with. You'll need, in all cases, an electronic charge controller. A simple diode will not prevent the wind generator from overcharging and burning out your lead acid battery. I purchased a "Chanyn" Model#CQ1210, for $ 55.00, on ebay. It has separate contacts for: Battery, Wind Generator (or Solar Panel), and Load (aka 12 Volt appliances). The charge controller will also prevent the battery from discharging too low, greatly extending the life of the battery.
Thank you for the pointers.
where can i get the generator? please give a web adress
shastalore (author)  electronic boy5 years ago
The exact motor I used for the generator is: 370-350-00 PE24113G 48VDC They sell for about $ 300.00, through the medical parts suppliers, but I bought mine from USA WindGen turbines, Athens, Texas, as a surplus item, for about $ 50.00. He also sells on ebay, as "otter5555", and he just may still have some of these on hand. I think he received some flack selling these motors, since some of his customers complained that they rusted out. But the quality of this motor/generator is excellent. Since it's portable, just treat it as a fair weather friend. Stay posted, as I will soon build an aerodynamic, weatherproof sheet aluminum jacket, to fit over the generator, with aluminum pop rivets.
luvit5 years ago
ah.. the moderm convenience of being rustic with nature. i'd add whistles to the blades so people would notice it.
Dr.Bill luvit5 years ago
Maybe 3 different sounding whistles would really whip things up !
Dr.Bill Dr.Bill5 years ago
And keep the monsters away !
shastalore (author)  Dr.Bill5 years ago
For the benefit of our readers: I'm personal friends with "drbill" and we enjoy razzing each other.
shastalore (author)  luvit5 years ago
The Air-X blades make a god-awful "hiss" that is clearly heard by anyone in close proximity to the generator. The blades are even made of black plastic, to appear serious, and dangerous. The spinning blades naturally appear and feel threatening to anyone who observes them up close. But from a distance, the wind generator is silent and is completely obscured by normal background sounds. Mounting a whistle on the blade tips would certainly affect the high-speed performance of the blades, as well as creating unacceptable noise in the vicinity.
you make me like it more. so i need whistles.
yachtmaker5 years ago
can the generator be used with a straight to inverter to provide AC for perhaps a small radio?
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