Chispito Wind Generator




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The Chispito Wind Generator was designed to be simple and efficient with fast and easy construction. There are no limits to what you can do with wind power. There is nothing more rewarding and empowering than making a wind powered generator from scrap materials. Most of the tools and materials in this manual can be found in your local hardware shop or junk pile.

For more information and inspiration on wind generator construction, please visit

Step 1: TOOLS

  • Drill
  • Drill Bits (7/32", 1/4", 5/16")
  • Jigsaw with a metal blade
  • Pipe Wrench
  • Flat Head Screwdriver
  • Crescent Wrench
  • Vise and/or Clamp
  • Wire Strippers
  • Tape Measure
  • Marker Pen
  • Compass + protractor
  • 1/4" #20 Thread Tapping Set
  • An extra person helps a lot!



  • 36" of 1" Square Tubing
  • 2" Floor Flange
  • 2" X 4" Nipple
  • 3 X 3/4" Self-tapping Screws

NOTE: if you have access to a welder, you can weld a 4" section of 2" pipe onto your square tubing instead of using the flange, nipple and sheet metal screws.

  • 260 VDC, 5 A continuous duty Treadmill Motor with a 6 inch threaded hub
  • 30 - 50 Amp Blocking Diode (one-way)
  • 2 x 5/16" x 1 3/4" Motor Bolts
  • 3" X 11" PVC Pipe

  • 1 sqft (approx) lightweight material (metal)
  • 2 X 3/4" Self-tapping Screws

  • 24" length of 8" PVC Pipe (if it is UV resistant, you will not need to paint it)
  • 6 X 1/4" X 20 Bolts
  • 9 x 1/4" washers
  • 3 sheets A4 paper and tape


Step 3: BLADES

Cutting Blades - makes 9 blades (or 3 blade sets) and a thin waste strip.

1. Place the 24" Length of PVC pipe and square tubing (or other straight edge) side by side on a flat surface. Push the pipe tight against the tubing and mark the line where they touch. This is Line A.
2. Make a mark near each end of Line A, 23" apart.
3. Tape 3 sheets of A4 paper together, so that they form a long, completely straight piece of paper. Wrap this around the section of pipe at each of the two the marks you just made, one then the other. Make sure the short side of the paper is straight along Line A and the paper is straight against itself where it overlaps. Mark a line along the edge of the paper at each end. Call one Line B and the other Line C.
4. Start where Line A intersects Line B. Going left around Line B, make a mark at every 145 mm. The last section should be about 115 mm.
5. Start where Line A intersects Line C. Going right around Line C, make a mark at every 145 mm. The last section should be about 115 mm.
6. Mark each line using a straight edge.
7. Cut along these lines, using the jigsaw, so that you have 4 strips of 145 mm and one strip about 115 mm.
8. Take each strip and place them with the inside of the pipe facing down.
9. Make a mark at one end of each strip 115 mm from the left edge.
10. Make a mark at the other end of each strip 30 mm from the left edge.
11. Mark and cut these lines, using the jigsaw.
12. Place each blade with the inside of the pipe facing down.
13. Make a mark along the angled line of the blade, 3" from the wide end.
14. Make another mark on the wide end of the blade, 1" from the straight edge.
15. Connect these two marks and cut along the line. This prevents the blades interfering with the others' wind.

Sanding the Blades
You should sand the blades to achieve the desired airfoil. This will increase the efficiency of the blades, as well as making them quieter.

The angled (leading) edge wants to be rounded, while the straight (tailing) edge wants to be pointed.

Any sharp corners should be slightly rounded to cut down on noise.


Cutting Tail
The exact dimensions of the tail are not important. You want about one square foot of lightweight material, preferably metal. You can make the tail any shape you want, so long as the end result is stiff rather than floppy.

Drilling Holes in Square Tubing - using the 5/16" drill bit

1. Place the motor on the front end of the square tubing, so that the hub part hangs over the edge and the bolt holes of the motor face down.
2. Roll the motor back so you can see the bolt holes, and mark their position on the square tubing.
3. Drill a 5/16" hole at each mark all the way through the square tubing.

Floor Flange Holes
This will be dealt with in the assembly section of this manual, as these holes are what determine the balance.

Drilling Holes in Blades - using the 1/4" drill bit

1. Mark two holes at the wide end and along the straight edge of each of the three blades. The first hole should be 3/8 " from the straight edge and 3/8 " from the bottom. The second hole should be 3/8 " from the straight edge and 1 1/4" from the bottom.
2. Drill these 6 holes.

Drilling and Tapping Holes in Hub - using the 7/32" drill bit and 1/4" tap

1. The Treadmill motor comes with the hub attached. To take it off, hold the end of the shaft (which comes through the hub) firmly with pliers, and turn the hub clockwise. This hub unscrews clockwise, which is why the blades turn counter-clockwise.
2. Make a template of the hub on a piece of paper, using a compass and protractor.
3. Mark 3 holes, each of which is 2 3/8" from the center of the circle and equidistant from each other.
4. Place this template over the hub and punch a starter hole through the paper and onto the hub at each hole.
5. Drill these holes with the 7/32" drill bit.
6. Tap the holes with the 1/4" x 20 tap.
7. Bolt the blades onto the hub using the 1/4" bolts. At this point, the outer holes have not been drilled.
8. Measure the distance between the straight edge of the tips of each blade. Adjust them so that they are all equidistant. Mark and punch each hole on the hub through the empty hole in each blade.
9. Label the blades and hub so that you can match which blade goes where at a later stage.
10. Remove the blades and then drill and tap these outer three holes.

Making a Protective Sleeve for the Motor

1. Draw two straight lines, about 3/4" apart, along the length of the 3" x 11" PVC Pipe. Cut along these lines.
2. Make a 45 degree cut at the end of the pipe.
3. Place needle nose pliers inside the strip that has been cut out, and pry the pipe apart.
4. Making sure the bolt holes of the motor are centered in the middle of the missing strip of PVC pipe, push the motor into the pipe. An extra person will make this a lot easier.


1. Place the motor on top of the square tubing and bolt it in, using the two 5/16" x 1 3/4" bolts.
2. Place the diode on the square tubing, about 2" behind the motor, and screw it into position using the self-tapping metal screw.
3. Connect the black wire coming out of the motor to the positive incoming terminal of the diode (Labeled AC on the positive side).
4. Connect the red wire coming out of the motor to the negative incoming terminal of the diode (Labeled AC on the negative side).
5. Center the tail over the square tubing, at the back end. Clamp your tail onto the side of the square tubing.
6. Using 2 self-tapping screws, screw the tail in place.
7. Place each blade on the hub so that all the holes line up. Using the 1/4" bolts and washers, bolt the blades to the hub. For the inner three holes, use two washers per bolt, one on each side of the blade. For the outer three holes, just use one washer next to the head of the bolt. Tighten.
8. Hold the end of the shaft of the motor (which comes through the hub) firmly with pliers, and turn the hub counterclockwise until it tightens and stops.
9. Screw the nipple tightly into the floor flange using a pipe wrench.
10. Clamp the nipple in a vice so that the floor flange is facing up and level.
11. Place the square tubing (and everything that is on it) on top of the floor flange and move it so that it is perfectly balanced.
12. Through the holes of the floor flange, mark the square tubing at the point of balance.
13. Drill these two holes using a 5/32" drill bit. You will probably have to take off the hub and tail to do this).
14. Attach the square tubing to the floor flange with two sheet metal screws.

For a longer life span of your wind generator, you should paint the blades, motor sleeve, mount and tail.



Use of Chispito Wind Generator - You will need a tower, wire, ammeter, charge controller/regulator, and a battery bank for your Chispito Wind Generator. Please refer to for more information

The tower is one of the most important components in your wind generator system. It must be strong, stable, easily raised and lowered, and well anchored. The higher your tower is, the more wind your generator will be exposed to. Guy wires must be placed at least every 18 feet of tower height. Guy wires must be anchored to the ground at least 50% of the height away from the base. For full tower instructions, please refer to our Tower How-To at

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292 Discussions


Question 1 year ago

I think it's hard to understand the exlpanations on Vela Creations. Can someone explain better with figures how to build the tower? I didn't understand why i have to dig 2 holes and what exatclty is the Base.


2 years ago

WOW! very well done instructable!!
Yours put mine to shame!
I found your instructable while doing a search for treadmill motors


2 years ago

Hello! I am a high school student and is planning on building a wind turbine for my project. Will this design be do-able for someone like me? How much experience do I need to take on this project? How much electrical energy does this produce and for what range of wind speeds? Any advice and replies would be greatly appreciated!


2 years ago

One other thing, i see someone saying there would be no drag if it was on the front of the caravan, if you put a wind powered fan in front of a wall it will not run very well, no power. The air needs to be able to flow through freely so it would need to be mounted on the side or top, nothing in behind it. If you mount it to the front of your truck the wind will go through the fan and then the AC condenser, oil cooler, radiator and then run into the engine, not as much wind resistance but there still is and you would need to run a lot of heavy wire clear back to the trailer batteries and a regulator in the middle some where so the batteries won't over charge.


2 years ago

I forgot to mention one thing about the motor and fan size. Any kind of a generator when under load will have resistance, if there is to much resistance and not big enough fan blades it will come to a stop or run very slow. I don't think you could use a plastic fan or even a cheap metal one either, think about the wind pressure and turbulence on top of the trailer and you would need to mount it very well or the wind would just rip it off.


2 years ago

There are pros and cons to putting one on the top of your trailer or using your truck alt. There will be some drag which will make the engine work harder using more fuel but it would probably be about the same as what your alt would pull from the engine anyway., most alt's pull about 15-20 horse from your engine at peak output.Think about this though, if you have 1 or 2 batteries in your truck and 1 to 4 batteries in your trailer plus all the other electronics and lights running, that is a huge load on that alt, plan on replacing the alt every so often, the alt's them selves don't go bad but the regulator inside burns up or the brushes wear away. The wiring from the truck needs to be the right gauge to handle that much power for charging the trailer batteries and will the fridge be running while your driving, most fridges pull 10 amps when on electric setting. Putting one on top of the trailer would be good for taking the load off the alt but they do have rpm limiters and if you were going down the road at 65-80 mph the blades would fly right off and i don't need to say much about what would happen if you drove under a low overpass. What i do, is i just charge my batteries all the way before i leave, get to my camp site, run my generator to charge the batteries back up if i was running the fridge while driving, if not then my batteries would still be charged and i would just set up my two solar panels and let them keep the batteries charged. No load on the truck or anything on top of the trailer. I have two 300 w panels that cost me $150.00 ea and a charge controller that i think was about the same. I have 4 6v deep cycle batteries hooked together as one big 12v battery, all the power in the world, no problems.


3 years ago

I am biding time (saving $) on solar panels for our Airstream, and was looking for a way to make a small wind generator to mount on top of the trailer to charge batteries while driving. Any reason why something like this wouldn't work? Is there a limit to how fast the blades/turbine can spin before it would create problems? I think I will likely find an old fan to use for the blades, as fan blades would likely be sturdier than the home made pvc blades mentioned here.

10 replies

Reply 3 years ago

As everyone else has already told you. You will loose energy, unless your turbine are (unlikely) more efficient than the generator in your car. So charging batteries from the turbine while driving are not that a good idea. Use the one from your car instead. Each transformation of energy from one form to another will give loss in energy (that is why stuff get hot when doing this, that is energy loss).
If that would be a good idea to charge batteries from wind while driving, Tesla cars would have that already. ;-)

While your car is standing still, it is a great idea, as a complement to your solar system.


Reply 3 years ago

You'd have better efficiency charging the batteries off your vehicle's alternator. Drag will burn more fuel than the extra draw on your engine. Plus no rpm, charge controller or water concerns


Reply 3 years ago

A fan connected to an alternator mounted on front of caravan would not add excessive drag to vehicle & if it was a hybrid it could actually aid in mileage by charging the batteries whilst driving


Reply 3 years ago

If using smaller blades, will drag really be that big of an effect (especially already towing a trailer?).


Reply 3 years ago

Drag, whether on the alternator or wind turbine will be minimal in both cases, just more on the turbine. You're already driving the alternator, so charging the batteries would be an inconsequential addition. When parked, the turbine would be the way to go. And you're not likely to overspeed it.


Reply 3 years ago

If I'm using smaller blades, would it really have that great of an effect (especially while already towing a trailer)? Plus, even while parked, if there's wind I'd be generating electricity.

And the trailer is of course already set up to charge from the alternator while towing.


Reply 3 years ago

Well it would induce drag which means your truck will pull harder, let alone it being extremely inefficient. Use your truck alternator. Spend the money you would put in this into a bigger amp output alternator and larger wires to the trailer.


Reply 3 years ago

Hi - using this to charge while parked is an excellent idea. Using it while driving is an inefficient one. There are power losses every time power changes form so driving to generate wind to generate electricity will waste more power than charging from your vehicle's battery system. You are right, in your later comment, that a smaller set of blades will cause less drag but, as a direct consequence, they will also generate less electricity.


Reply 3 years ago

kidjedi, If you are thinking of having this running whilst driving, I would suggest that a Savonious Rotor (mounted on the roof of the van) would be better and far easier to instal. As it is low profile it won't be on a mast and there is less bracing required, to support against the wind flow.


Reply 3 years ago

Yeah... I was actually already looking at switching the rotor design to Savonious. Thanks!


3 years ago

"There is nothing more rewarding and empowering than making a wind powered generator from scrap materials."

Really? NOTHING?

2 replies

Reply 3 years ago

NOTHING. Except making TWO wind powered generators from scrap materials. Or one wind powered generator out of toothpicks.


Reply 3 years ago

Then your life is significantly different from mine.