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My Experience with Wind Turbines

Thank for taking the time to document and share all of your years of experience on wind power generation with us. Your observations and conclusions, not to mention your excellent writing style, is invaluable. Whether someone pursues wind power or not, you’ve educated us all.
 
Thanks @Marobel (and everyone else, too)
These projects have been immensely satisfying and productive. I've learned a lot from it, and continue to do so. So naturally I also want to share some of it with others.
 
welcome Sparweb. I am happy that you decided to take the plunge here.

I am sure here one can also thrive.

My personal experience here is that this community gives a lot of freedom of expression but is not easily convinced.

I am working my butt off to make that happen and in that process I might have some questions for you. :)

Once again welcome!
 
Hi
So just putting together the 2 posts you made, you want a RE source like wind that can sustain your battery bank overnight, and I suppose you have solar for daytime generation. You mentioned that your consumption is about 500W overnight. That seems a bit high. Could be a lot of things, like electric heat or a central furnace fan, but instead of guessing, what can you say is the cause of this consumption?

In the winter, the overnight period is literally 14 hours of the day (for someone in Illinois) meaning your overnight usage is about 8 kWh. From an 800 AH battery bank (assuming it's wired at 48V) then you can store about 38 kWh. More like 30 kWh to be realistic. So it seems like you have lots of capacity. Have I calculated wrong?
Thanks for the reply. Yes, 500w is high but half of that is refrigeration needs. We purchase meat frozen vegetables in bulk. 200 watts of that 500 will be attributed to a crypto miner. I have a 24v system with a 6kw solar array. I will be adding 2kw of solar this spring to assist with A/C needs. I should have went with a 48v system but I didn't so it is what it is. Yes, I've spent a lot of extra money on wiring due to my personal beliefs in oversizing but I ended up with a robust, safe setup.
 
Good question. Here are the performance charts I developed in 2020.

I built a datalogger to collect my own data. I bench-tested the generator before installing it in the wind turbine, and one of the checks on the datalog that I did before accepting its data was to verify that it was recording values consistent with the original bench test. You can see the data below collected from 3 separate logging runs in 2019. The reason they are different is because the battery voltage was substantially lower on the 20th (green dots). I measured this during my bench tests so I confirmed this, too.

View attachment 268791

In the next graph below, the wind power values (red line) are basic calculations based on the wind power law. For the datalogs used for my performance evaluation, I included data from my weather station for wind speeds and barometric pressure (and air density). The output power relative to wind speed is found by just crossing the measured power with the speed at that moment. But that hides the complexity of the calculation because using the raw data to do that would lead to a ridiculous and useless hash of dots. To get reasonable averages, I needed hours of data to be collected, even though the data was sampled and recorded by the datalogger every 10 seconds or so.

To manage all of this data, I binned the data in 1-minute chunks, and tried to use statistical methods consistent among the data reduction that the weather station uses (automatically, which I can't control or change) and the data from my datalogger.

Note that the "input power" curve is created by cross-referencing the bench test data, where I collected the generator's input and output power measurements. All of the in-situ values of wind turbine output power were correlated to the bench-tested input power values.

View attachment 268790

The wind speed and associated turbine rotor speed data allow for a fairly direct calculation of Tip Speed Ratio (TSR). When I started collecting datalogs of my wind turbine over a decade ago, I began to learn that the things people like to say about TSR is often inaccurate, sometimes misleading. I went back to basics with some fluid dynamics textbooks and confirmed that TSR should do this with increasing wind speed. I had designed my wooden blades for TSR=5, so I guess I hit it right on.

View attachment 268789

Finally here is the number we're all happy to see, the Coefficient of Performance of the wind turbine (Cp). Really happy with the results when I was able to demonstrate this. Note also that the peak CP coincides with the actual measured TSR matching the as-designed TSR of the wooden blades. After many tries, I seem to have gotten it right. It was a satisfying pay-off for 15 years of learning and experimenting.
@justgary

Please see here someone that has been through the motions. And his graphs look realistic.

Let us use this then as a baseline for what is the PMA concerned.
 
Hello @Cris2112
That clarifies your system a little better. At 24V your 800 AH makes for about 15 kWhr, am I right?
That's still a lot of storage, and it would carry 500W for a full day. That sounds great, but....

I have a 6.5 kW solar array, too, and in the winter the angle of the sun is so low that it usually doesn't produce more than 10 kWhr per day. More like 7 this January. You might do better than me, but at a guess Illinois has plenty of cloudy winter days with low sun angle too. Clearly that's not enough to support your loads or your battery bank - nor both at the same time.

Because you have a battery bank, then a wind turbine is a reasonable DIY option. Your approach to a DIY wind turbine has to be based on what you can do, which is limited by your local zoning, size of your property, your neighbors, and your familiarity with fabrication with many materials, and attention to detail. I don't know you and I just joined DIYSF so if you're written about these things before, forgive me I haven't seen it.
 
in a private exchange that you tried but gave up on your VAWT experiment(s).
Private exchange? Maybe, but it's hardly a secret. I tried building several but they were all next to useless. VAWT's give wind energy a bad reputation because they are over-promised and under-designed. Every one of them. Even the commercially "viable" ones have suffered from reliability and maintenance issues that doomed them to a short service life.
 
Hello @Cris2112
That clarifies your system a little better. At 24V your 800 AH makes for about 15 kWhr, am I right?
That's still a lot of storage, and it would carry 500W for a full day. That sounds great, but....

I have a 6.5 kW solar array, too, and in the winter the angle of the sun is so low that it usually doesn't produce more than 10 kWhr per day. More like 7 this January. You might do better than me, but at a guess Illinois has plenty of cloudy winter days with low sun angle too. Clearly that's not enough to support your loads or your battery bank - nor both at the same time.

Because you have a battery bank, then a wind turbine is a reasonable DIY option. Your approach to a DIY wind turbine has to be based on what you can do, which is limited by your local zoning, size of your property, your neighbors, and your familiarity with fabrication with many materials, and attention to detail. I don't know you and I just joined DIYSF so if you're written about these things before, forgive me I haven't seen it.
I live in a farming community with no zoning for private solar or wind production. I also live amongst a commercial wind farm with 134 turbines so lack of wind is definitely not an issue. I'm fairly handy when it comes to DIY mechanical projects.
My ultimate goal is to have a hybrid wind / solar system that rarely needs the backup generator to get the battery bank charged up to a reasonable level during poor weather conditions. I have a dump load but I do not want to utilize that for excess power generated from a turbine due to the fact I use this load, a water heater, to preheat our domestic water. On sunny days I heat the solar water heater up to 180 degrees. If I wanted to rely on this dump load to handle excess wind power I would have to limit the power I dump during the day so I could have room for that excess wind power at night. All that being said, I want a DIY unit that will max out at 500 watts therefore never causing overcharging issues. If I'm missing something or seem to be confused please elaborate. Thank you
 
I live in a farming community with no zoning for private solar or wind production. I also live amongst a commercial wind farm with 134 turbines so lack of wind is definitely not an issue. I'm fairly handy when it comes to DIY mechanical projects.
My ultimate goal is to have a hybrid wind / solar system that rarely needs the backup generator to get the battery bank charged up to a reasonable level during poor weather conditions. I have a dump load but I do not want to utilize that for excess power generated from a turbine due to the fact I use this load, a water heater, to preheat our domestic water. On sunny days I heat the solar water heater up to 180 degrees. If I wanted to rely on this dump load to handle excess wind power I would have to limit the power I dump during the day so I could have room for that excess wind power at night. All that being said, I want a DIY unit that will max out at 500 watts therefore never causing overcharging issues. If I'm missing something or seem to be confused please elaborate. Thank you
You are correct. I have a 24v system with an 800ah battery bank. I'm not against adding another 400ah if needed.
 
Thanks @Marobel (and everyone else, too)
These projects have been immensely satisfying and productive. I've learned a lot from it, and continue to do so. So naturally I also want to share some of it with others.

You’ve provided more details than any other person ever has before about building your own small wind turbine. I think we’ve all really appreciated it; I know I sure have.

But there’s one critical detail that I’ve not seen you mention, sorry if I’ve missed it.

What about the actual kWh production over time? Most of us can look back at the daily/monthly/etc. kWh’s produced by our solar systems. Can you provide something similar? THX
 
What about the actual kWh production over time?
Oz,
Great question!
I don't have a perfect answer, nor a simple one. I messed about with a datalogger for years, and electronics isn't my strongest suit. I had one working rather well but I kept wanting to change and improve it. In January 2023, I added kWhr totals to the output, and started keeping track of that. That summer, I got more ambitious and tried to add a WiFi antenna to it. The WiFi worked for several weeks and then quit. The failure of the WiFi board seems to have damaged something because the datalogger stopped working after that.

I haven't posted details about the datalogger - probably worth a post of its own. The one I was using then was based on an Arduino Mega board. I decided to start fresh which would avoid frustration if the old board really was damaged, and I wanted a fresh start. The new datalogger sits beside me on my desk, waiting to be installed (too cold these days!)

Here's the data I collected from January to July 2023.

1738127061963.png
 
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OK that post worked.

[I tried a simple copy-paste from Excel to do that. Usually when posting an image on a forum, I have to save the image as a file and then upload the file. This is more convenient. Do I owe thanks to Wil Prowse for this feature?]

Just to make sure it's known to everyone reading the graph above, the data is only the blue squares. The black line is a curve-fit to see where the trend is leading. The trend line is believable because summer is not a very windy season for me, but fall, winter, and spring are. So the slope of the curve should be shallow between June and August. It gives a very rough forecast of 1000 kWhr per year, but I was not able to validate that prediction by collecting the actual data. As I said, I did something stupid to my datalogger before a whole year of data was collected. The damage made it stop taking accurate current measurements.

That trouble aside, there's a way to put that energy statistic in context. Stand by, I'll collect some more charts...
 
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My ultimate goal is to have a hybrid wind / solar system that rarely needs the backup generator
Hi Cris,
Three cheers for your goal. I'd love to do the same but my wife is putting her foot down and this summer a back-up genny will be installed here. I try.

I get the balance you're trying to strike with the water heat. Excellent purpose to the diversion load, so I wouldn't suggest you change that. Especially if it is working well already.
Adding batteries isn't a cure-all because you can end up with too much. Oversized battery banks can be under-charged by the PV/Wind systems if they aren't big enough to overcome the loads. So instead you end up with a battery bank that "could" carry you for days but doesn't because it's often still crawling up to float by the end of the day.

You might have the answer when you mentioned the combination of additional battery and wind. Since wind is less consistent than PV, there's the advantage of having more storage capacity ready for the literal windfall of a windy day. You might have also heard of the way PV and wind can be complimentary, since cloudy days tend to be cloudy because of bad weather - often windier weather. The amount of battery to add needs to match the average generation from wind (the match doesn't have to be perfect).

I wouldn't worry about capturing all of the energy that is generated from wind on the really windy days. Yes it's energy coming in, but the battery is already full so why make it complicated? Shut down the turbine, or dissipate the excess wind energy to an air heater, wherever you want to put it and the buzzing noise won't bother people. The number of days where its (a) continuously windy for long enough to take the battery bank to float and (b) the water heater is already at 180 degrees, might be counted on one hand per year, for you. The contribution from PV into your water heater seems to be dominant and the preferred system to heat your water, even with wind.

My guess is that if you add 400Ah of battery at 24V you might want a WT that can generate about 500 kWhr per year.

Did you ever subscribe or read Home Power magazine? If so do you remember their annual WT comparison articles?
 
@Cris2112
I thought of another thing... what happens at your water heater when the diversion heater is shut off by the thermostat?
Different people have done different things, in a DIY sense. I haven't actually done this myself, though.
Wondering if you install a second diversion load, could you set it up to be switched in, as the water heater is switched out?
 
@OzSolar
Following up on my total energy comments, here's a prediction I made in the year 2020 based on measurements of the wind turbine's performance, and cross-referencing that data to local wind speed statistics.

Comparison3.png

There are 3 things being compared on this chart. There are power curves for 2 wind turbines, mine called Zubbly, and a Bergey XL-1 which is a similar size but obviously quite different. If you haven't seen a Bergey, google it and you will see it's not the same as what I built. The power curves show mine flattening out at 500W, while the Bergey can claim over a kiloWatt power. I got the Bergey data from {EDIT=1 Feb 2025} a test report published by the NREL. a spreadsheet written by Mike Bergey which can be downloaded from the Bergey Windpower website. I also have NREL test reports for Bergey Excel-R and Excel-S models, some of which pre-date the SWCC program. {/EDIT}

The 3rd line (black) is the average wind speeds at my home. The distribution is simplified as a Weibull distribution which is typical in most places. There's a peak, at about 3.5 meters per second, and because there are lots of times in the year the wind is stronger, the average on balance is about 5 meters per second. Looking down from the peak wind speeds you can locate the corresponding performance of the two wind turbines in these conditions. The grey area is where my Zubbly out-performs the Bergey. That also coincides with the most common wind speeds where I live. In 5 m/s wind my Zubbly produces 250W while the Bergey only gives you 100. Since this it true over 60% of the time, my Zubbly is more likely to be producing more at any given time.

The bottom line is that I would expect a Bergey XL-1 to generate less than 800 kWhr per year, but my Zubbly could do more than 1000 kWhr, where I live here in southern Alberta.

I was sooooooooooooooo close to proving that, before I muffed up my datalogger! Oh well Zubbly will probably last a long time and I'll have a chance to try again with my new datalogger.
 
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Adding batteries isn't a cure-all because you can end up with too much. Oversized battery banks can be under-charged by the PV/Wind systems if they aren't big enough to overcome the loads. So instead you end up with a battery bank that "could" carry you for days but doesn't because it's often still crawling up to float by the end of the day.

That is a lead-acid issue. LiFePO4 might fit the bill nicely.

Of course controlling loads to use surplus and to avoid over-discharging can be part of the system.
Mine is grid-backup and I will lose net metering in a month. Then the plan will be to peak shave with goal of zero export, zero import. Run electric heat if PV generated power available, switch to gas heat (1/8th the price of electric resistance heating) below some battery SoC.
 
@Cris2112
I thought of another thing... what happens at your water heater when the diversion heater is shut off by the thermostat?
Different people have done different things, in a DIY sense. I haven't actually done this myself, though.
Wondering if you install a second diversion load, could you set it up to be switched in, as the water heater is switched out?
I have not subscribed to any wind related magazines or blogs. I'm just now at a point where I can take on a wind project. As far as the water heater goes, I have a 24v relay that is controlled by a Shelly Smart Switch. The switch is powered through one of my Epever controllers. Normally on a sunny day I will log into my Shelly app around 10am and turn on the dump load. I have a 24v, 600 watt element in the heater so it can take up to 5 hours to produce 180 degree water depending on the waters starting temp. I believe the tank is either 28 or 32 gallons.
 
That sounds really effective. Is this a pre-heater tank, separate from a main heater, or is it a second heating element in one main water heater?

I haven't given this as much thought as my other RE projects, but maybe doing so would be a good RE application in my house, too.
 
Nice looking, interesting, but totally impractical, with horrid ROI. It can be windy any time day or night, but popping a 50' tower up to get a few killowatt hours seems like a lot of effort vs a solar panel or three.
 
Its not really one or the other, I have solar panels and a turbine hooked together for one system. Its much more pleasant to watch the spinning blades than watch a solar panel. And it helps push a little charging during the night, (like last night with 40mph winds, when the grid power is likely to go out from fallen trees). Then there is the challenge of the "steampunk" turbine itself versus the "electronic" panels. So, for me, I like fussing with the turbine, something I really cannot do with the panels.
 
I have not subscribed to any wind related magazines or blogs. I'm just now at a point where I can take on a wind project. As far as the water heater goes, I have a 24v relay that is controlled by a Shelly Smart Switch. The switch is powered through one of my Epever controllers. Normally on a sunny day I will log into my Shelly app around 10am and turn on the dump load. I have a 24v, 600 watt element in the heater so it can take up to 5 hours to produce 180 degree water depending on the waters starting temp. I believe the tank is either

That sounds really effective. Is this a pre-heater tank, separate from a main heater, or is it a second heating element in one main water heater?

I haven't given this as much thought as my other RE projects, but maybe doing so would be a good RE application in my

That sounds really effective. Is this a pre-heater tank, separate from a main heater, or is it a second heating element in one main water heater?

I haven't given this as much thought as my other RE projects, but maybe doing so would be a good RE application in my house, too.
Yes, this dump load water heater is places on a heavy shelf in my garage. Water to be heated runs into this unit first where most days it's heated to 180 degrees then as we use hot water it flows into our 40 gallon propane water heater, set at 140 degrees, in the house. Feeding that 180 degree water into a our main water heater saves a tremendous amount of propane 8 to 9 months per year.
 
So good to see Sparweb active... I'd been on FL for a year (DanG) when he joined and tagged along on 5500 posts of his - he's a World Book of knowledge and always kept it 99.9% civil minded, just saying he really has been there and done it right, eh?

Something to mention is load control, (EDIT: for new or casual hobbyists) standing at the tower trying to short out the drop lines while the turbine blade tips are runaway & going supersonic with machine gun sonic booms should not ever be part of a learning curve.

It is kinda counter-intuitive but when the battery is charged it goes open circuit and the unloaded turbine can runaway and furling out of the wind becomes somewhat academic - load resistors or heater elements, wiring & switches etc. follow Murphys' Law - believe Sparweb when he says he builds heavy circuits!

Anyhow - I nabbed a dan-built 10' jenny, SN124 long ago when an eBay auction went stagnant and its still in the box, I bought a bit of land east of Fargo that is infested with big trees, oops.

Sparweb - is there a current source of ghurd controllers anywhere in creation? Or... is there an equivalent that has been TTD and perfected?
 

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