We built a 1000 watt wind turbine to help charge the battery bank that powers our offgrid home. It's a permanent magnet alternator, generating 3 phase ac, rectified to dc, and fed to a charge controller. The magnets spin with the wind, the coils are fixed, so no brushes or slip rings necessary.

Update: DIY Amp Hour meter for monitoring charge!

All about homebrew wind and offgrid power systems, the complete reference!
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Step 1: Build the magnet disks

We had 12" steel disks hydro cut. We cut a template for mounting the magnets. Then we mounted 12 grade n50 magnets around the outside edge. We then built a form, and poured the resin with hardner.

Step 2: Build the coil disk

We wound the nine individual coils, soldered them in a 3 phase wye configuration, and encased them in resin. We used 35 turns of 2 parallel strands of 14 gauge enameled (magnet) wire for 12 volts. Use 70 turns of single strand for 24 volts. # 3 phase diagram shown here shows 3 stator coils. each of those coils is actually 3 coils in series. coils 1,4, and 7 are series together, 2,5, and 8 are series together, and 3,6, and 9 are series together.

more details, see the following page 15 for the series star, 1-y diagram.


Step 3: Build the bearing assembly

Picture of Build the bearing assembly
Two Harley Davidson wheel bearings are inserted into the pipe, with a smaller pipe locked between them to keep them in place.

Step 4: Construct the blades

The blades are 2" x 6" pine, cut at 10 degrees on a table saw, and sanded into a rough airfoil. Not perfect, but close enough.

More can be found at

Step 5: Further Reading

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Hey, just a quick question I've seen in other designs that all the coils are flush to each other and in this one they are spread out. I was just wondering if you knew if there was a difference between spreading them out like yours or having all the coils touching each other?

sspence (author)  guitarplayr215 days ago
coil size is dependent on magnet size. This is a larger diameter disk, so they don't touch. if the disk was smaller, the power pulses could be a bit smoother. Doesn't matter for battery charging.
puppy_00724 days ago
Hi there ! If i use 20AWG wire and 125 turn with 9 coil star connect .24 magnet 2 rotor at N50 1-1/2 dish . Is that will be good ? Can i get 10-15 amp at 12V with 200-300 rpm . Please thanks
sspence (author)  puppy_00724 days ago
You may very well, depending on wind availability. experiment.
Thanks alot
puppy_00724 days ago
Hi there ! Please tell me how many amps you get at 12v ?
How many rpm at 12v . Thanks in advance !
sspence (author)  puppy_00724 days ago
80+ amps at 650 rpm
Hi ! Thanks for your reply .
Is there any way i can get 12V at 200 or 300 rpm .
I only need 10 or 15 amps at 12V . Thanks
sspence (author)  puppy_00724 days ago

You would have to wind many more turns on the coils to develop voltage at lower rpms. at lower current, you can wind with smaller diameter wire than we used.

sspence (author) 1 month ago
yes, the strength of the magnets also affect power output.
JohnT121 month ago

I'm curious as to how you determined that this is a 1000 watt generator. I'm working on a small model right now and am not sure what I'll get from it when it's done. About 5 inches in diameter.

I must also say that I've given up completely on lead acid batteries. When yours give up the ghost, check out LiFePo4 cells.

sspence (author)  JohnT121 month ago
Ohms law. number of coil turns, wire gauge. rpm. blade length, wind speed.

Not interested in Lithium based batteries. NiFe, yes.
JohnT12 sspence1 month ago

Thanks for such a quick answer. I also assume the power of the magnets play a factor. I'll have to look in to NiFe batteries. Sounds interesting. I love this stuff.

John kb8uhn

NRG4UandMe1 month ago

Excellent - this is a great share ! Thanks !

birddseedd1 year ago
Ya know. this kinda stuff sounds great, but, it really isnt all that piratical if you live on grid. average it out i spend 100 bucks or so a month. for me to buy a grid tie inverter or a battery bank/inverter/charge controller is going to cost me 3 grand. thats a 100 dollar a month loan, and i don't even have power yet. Even building my own solar panels will still cost me around 8 grand total. Thats over 150 dollar loan. I would be paying more money.

But how long would your loan last? and long will you the power company? No Brainer.... I would rather pay for own for 5 years instead a lifetime for power companies crap

A 25k loan over 5 years is near 500 bucks a month. sure it only lasts for 5 years, but i could invest that 300 dollars a month for 5 years and gain a whole heck of a lot more money than i would ever save in electricity.

then why are you worrying about costs if you clearly know how to make lots of money?

Because right now i have to invest 1500 a month+ into my company. Itl be that way for a couple more years
But after 5 years ALL of that money could be invested or saved. One never knows what the future may hold, if there even is one. I would rather my money be used for me and my family, now or for down the road freedom. What if the near future brings a collapse of our economic system? That money you would be investing will no longer exist and there will be no more power companies to provide power. We should be moving each dwelling towards self sustainability.
sspence (author)  birddseedd1 year ago
So don't live on grid. I spent $20k on my power system (complete), and immediately saved the $30k the power company wanted to extend the lines to my property.
you must live waaaaay out in the boonies, must be nice.

where i live it is 10k a pole. 30k is 3 poles which is merely a stones throw to the grid. This could be a a 3 acre parcel of land which is not much and very common. Birdseed, you should equip yourself with the proper information before you ignorantly speculate against the authors advice. Spence is very highly trained and educated in this exact field. Neither you nor I are, so arguing a reasonable explaination seems rather foolish to me.

I forget, what are we arguing about?

The issue is i don't have to spend any money getting electric to my house. its already there, all i have to do is buy the electricity. so, 100 bucks a month on electricity, or 20 grand on my own power system.
sspence (author)  birddseedd1 year ago
So why are you even bothering to comment on this instructable. This is for offgridders and diy tech heads. I don't comment on knitting instructables and tell them how they should buy their clothes at walmart ......
because i am trying to find someone who can show me an affordable way of doing it. and on grid vs off grid is not really an issue. its going to cost about the same, if not more.
sspence (author)  birddseedd1 year ago
Good luck. It's not about saving money in most cases, it's about independence. being able to build beyond the grid.
I want to save money. just not sure if its worth the 5 year investment till im in my last home
sspence (author)  birddseedd1 year ago
This is for tinkerers. you have to be handy, and love to build stuff. you probably won't save money. it's a good back up for a solar power system to keep the batteries charged when the sun isn't shining.
If i had 10 of them. Although i don't have space for 10 of them. unless i line them up on my roof. hmm. how much did this cost to build?

roof? screw that put them on yr out side walls. less snow to cover them. plus is the fire department in yr town trained to handle the solar problems from a house fire. go put the m on yr walls instead.

sspence (author)  birddseedd1 year ago
It will cost about $1k to build. You can't put them on your roof. They need to be 30' higher than any obstruction within 300'.

well more u learn the better the choices. also think abjut wat u use in yr home as well. swap to led lighting 4 example can? save u another 20 bucks or so in power. dont go to CFL(s). theyill hurt u even more.

again its how much u can afford to pay up front. if u go biuld it it yr own self yes learning an mistakes aside uill be better off in the long run.

Wouldn't you basically need the same or simular inverter and/or battery bank for wind or solar? And when talking about expense, if you can go one way or the other or both, then you should.

yes, inverter is needed for any energy source.

as far as wanting to be self sustaining, that is a different subject.

You can get grid tie inverters on ebay for $100-$500. About $250 for a 3k watt which should cover a lot of your power.

Hey mykiscool, can you please show me one. when i looked they were $3500. I need a 10k watt inverter.

sspence (author)  mykiscool8 months ago
They don't work with this wind turbine. Please limit your comments to the topic of the instructable.
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