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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zeffur1 month ago

What is the diameter of the area in which your blades turn?

To achieve 1 kW of *actual* output, what air speed is required to turn your blades?

sspence (author)  zeffur1 month ago
8' blades (16' diameter), 600 rpm (25-28 mph).
jmcebula3 months ago


I'm building a similar project for my final class at ITT, (to then be installed in my home). I constructed the turbine using 12 n42 magnets on a 10" disc with 12 coils of 18ga magnet wire (4 wired together in series, 41 turns each to produce ~14V output). I then hooked a 50W 12V lamp up to the outputs, and got nothing. My coils are only about 2" wide total, so I'm thinking that I am inducing the same current in both directions in my coil, therefore negating any effect.

I took not of the size of your coils vs. the size of your magnets, and thought they were about twice the length. I have tried a similar set up but with no luck.

Also, I have my magnet polarity so that the N/S axis is tangential to the circle. What direction are the N/S axes on your magnets?

Thanks in advance! (attached is my turbine, showing the size ratio between magnets and coils.)

jc wind turbine.jpg
sspence (author)  jmcebula3 months ago
the poleof the magnet face the coils, and alternate s up, n up, sup, etc. The coils also alternately reverse.
jmcebula sspence2 months ago

Thanks for the advice. Further research into Faraday's law (indicating that it is the change in magnetic field) lead to the same conclusion. I have since redone the rotor. However, I am still not getting any output from the turbine (measuring current through a 20W 8Ohm resistor to ground). I had thought my problem was that I was improperly using a bridge rectifier as a blocking diode, but when I hooked the resistor directly to the output of the coil I had no current either.

I also have my generator set up in delta configuration. I saw that you used star configuration, but I wasn't sure where you ran the neutral to. I have seen other star setups that lacked a neutral, but again this didn't seem to work for me when I set it up this way. I reconfigured to delta configuration without success either. I'm starting to think my coils are too small, but I don't want to re-wind bigger coils if I don't have to.

Any tips or suggestions? Thanks again!

jmcebula jmcebula2 months ago

Also, what did you mean by alternating the coils? One winds Clockwise, the next Counter? Did you do that within your series or is A clockwise, B counter, C clockwise?


sspence (author)  jmcebula2 months ago

Flip the coil over. You can read more on this in

brendargh2 months ago

Did you sell your excess power to a utility?

sspence (author)  brendargh2 months ago
No, I was not connected to a utility.
mykiscool2 months ago

"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." How many would you do and in what configuration to get 48 volts? I noticed that you doubled the turns and halved the strands, but since I can't have a half strand, do I do four times as many turns?

sspence (author)  mykiscool2 months ago

144 or so turns of 18 gauge. We doubled up on the 14g stands at 12v because one strand of 10awg was to thick to wind. As the voltage goes up, the amps drop for a given wattage, so smaller, easier to wind wire is used.

omid shakeri3 months ago

intresting job!!

mykiscool3 months ago

Hey Spence, could I use a rectifier like this connected to coils? It's quite cheap it seems like I could buy cheaper than I could make when I combine parts and labor:

birddseedd8 months 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.

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.

sspence (author)  mykiscool3 months ago
They don't work with this wind turbine. Please limit your comments to the topic of the instructable.
mykiscool sspence3 months ago

If grid-tie inverters don't work with this wind turbine, please tell me why. I'm in the process of building this turbine and would like to connect it to my grid-tie inverter. How can I make this turbine compatible.

It does work with grid tie inverters. I don't know why he would think it wouldn't
sspence (author)  birddseedd3 months ago

No, it does not. Why do I think that? Maybe because I'm a wind and solar power designer, installer, and 30+ year electronics veteran. This unit must be used with a battery bank and a diversion load controller.

mykiscool sspence3 months ago

Oh, ok thanks. That clears it up. So it should still work if I connect this to a charge controller and then to batteries and then to an inverter as I'd planned. At first, I thought you meant it won't work at all.

sspence (author)  mykiscool3 months ago

There were a number of posts referring to the inexpensive PV mounted direct to grid inverters. Those will not work. A battery type grid tie inverter (Outback GTFX) will work.

If it works with a load controller, it will work in an inverter. A wind turbine still outputs 12v dc, which can be used by an inverter, or battery charger.

sspence (author)  birddseedd3 months ago

micro grid tie inverters don't typically run on 12vdc. still need a battery to keep wind turbine from self destructing, as micro grid tie inverters turn off when grid goes down, and wind turbine will freewheel without a load.

^^^ what he said

What doesnt work with it?

sspence (author)  birddseedd3 months ago

solar type Grid tie Inverters do not work with this wind turbine. This unit is designed to charge batteries for off grid applications. Some inverters can take battery power and sell back to grid, but not the units that were being discussed which are designed to connect a solar panel directly to line power.

The turbine is just the source, you can do whatever you want with the energy.

sspence (author)  birddseedd3 months ago

You might think that, but this source has particular parameters that need to be met to keep it from self destructing. You might want to take the word from the guy that built it :-)

In michigan i would have to have 10k watt. for a grid tie inverter i cant find one on ebay. if i wanted to go off grid, im still looking at 10 to 15k
sspence (author)  birddseedd8 months 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.
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)  birddseedd8 months 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)  birddseedd8 months 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)  birddseedd8 months 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)  birddseedd8 months 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'.

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