Unsuccessful wind turbine story

[KMac55]

Nice tall tower at 70 feet. If that is sufficiently higher than the trees which are within a couple hundred feet of it you could be up in a range where there might be wind worth harvesting. The tower on a deal like that is the most difficult part, and often what people skimp on, resulting in no real power collection potential.

I don't understand your turbine choice as most small turbines with more than 3 blades loose a lot of efficiency. It is counterintuitive for some folks, but in reality the general rule is that more blades equal less power (although 5 blades can help prevent overspeed and still do well in lower wind for some turbines). The charge controller you have could be a problem too - looks sort of relay-based . There are some decent cheap charge controllers for wind with a boost circuit so you can gather more watts in lower wind that otherwise might be wasted in a 24 or 48v system. They also usually have an electronic shorting brake to slow or stop the turbine in strong winds or when charging voltage target is reached. I've had a nice 600w Chinese turbine running for a couple of years, and it works fine here on the plains, and produces power when the solar doesn't. It is programmed not to run at as high a target voltage as my solar does. I don't need it to compete with solar, just supplement the batteries when solar energy is absent. I've got hundreds of kilowatts out of it for my off grid weekend cabin, and it often keeps by batteries topped off all night.

I guess what I am saying is the turbine and controller you have might be the problem. There are relatively cheap good solutions out there, and maybe if you really want wind power you should scrap everything but the nice tall tower (which probably is the most expensive and difficult part). The heavily advertised turbines with outrageous claims are garbage, but some nice ones are out there - mine is Hy-600 made by Hy Energy in China and it is fairly heavily built - no problems, it just works for me. Remember, the diameter of the turbine rotor blades (swept area) sets the outer limit of the power it can collect, and the size of the windings determine other limits and characteristics of the power collected, like voltage at a certain RPM. Unreal claims of power production that are too good to be true are lies. The laws of physics are the same for all wind turbines.

Do a lot of research. The guy in this video link (below) has figured out some of the issues I'm trying to explain and has a few videos you could review because it just works. His charge controller is excellent for his small Chinese turbine that has been running well since I've been following him. In any event, since I have the same controller I found his stuff interesting, and I know it is great from my own experience.

Good luck.

 

[OzSolar]

Good evening everyone! I’m here to post what at this point feels like a complete failure. Partly due to me being gullible and used to dealing with honest people and partly due to someone being willing to sell me what I asked for ??‍. A little back story on my system, started with solar and fla batteries. Decided to supplement the solar with wind to help my aging batteries make it though winter nights. Wish I had found this forum before I made the jump… would have saved me so many headaches and a pile of cash…

After the turbine debacle I found Wills videos on YouTube and with so much help from Filterguy here I ended up with 32 eve 280ah cells and 4 overkill bms’s for 1,120ah at 24v. Absolutely love the batteries, love the new updated system layout and all is well. I need more solar but that will come in the future. Those are more straightforward.

Now comes to the thing that keeps me up at night thinking what to do… this dang wind turbine. I want it to work so bad, I think they’re cool, love seeing it operate and love the idea of it making a little power on those cold low solar winter nights.

What I already have in place, a 70’ tall tower, 300’ of 10-6 fine stranded copper wire 600v insulation buried from said tower to my batteries and charge controller, a 24v “2000watt” (ha ha ha right) Missouri wind and solar freedom 2 9 blade turbine, and their charge controller with a dump load. Also have 4 6v lead acid batteries that aren’t completely dead to do testing on if needed. My problem is the huge wire run (ran it by Missouri wind and solar, they said it was no problem) (real world huge massive freaking problem!!!) voltage drop would make it to where the turbine wouldn’t produce a high enough voltage to charge the batteries unless we had 30+ mph winds.

If you’re still with me, any advice? Scrap it, pull the wire up tear the tower down and accept defeat? I don’t want to accept that but I just want to hear others ideas too lol.

I'm terribly sorry for your experience. I've been there. Here's my story, After 30 years of trying to make it work I can say that small wind does not work. The end.

 

[upnorthandpersonal]

Wind doesn't scale to small turbines. You're dealing with two fundamental issues:

- The Betz Limit
- The Power in Wind equation

The Betz Limit is basically a theoretical number of the maximum efficiency you can possibly get. At most, only 59.3% of the kinetic wind energy can be used to spin the turbine and generate electricity. Remember this is a theoretical limit; in practice, you're going to be closer to 40%.

The Power in Wind equation is given as:

P = 1/2 x ρ x A x V³

Where:
P = power in Watts
ρ = air density (kg/m³, at about 1.2 at sea level)
A = Swept area of the blades (m²)
V = Velocity of the wind

So, no matter how good your turbine is, you will get in practice at most 40% of the wind energy converted to electricity. To capture the wind energy in the first place, you have two variables to increase (one in your control, the other not): swept area and wind velocity. The smaller you make the turbine, the faster you need to spin to make any meaningful energy. The only variable you control is the swept area, which means making the blades as big as possible. Also notice that the velocity is cubed in that equation, so you'll generate much, much less power at low wind speeds; don't assume this is linear or even exponential!

In other words, it doesn't work because physics.

 

[KMac55]

Wind doesn't scale to small turbines. You're dealing with two fundamental issues:

- The Betz Limit
- The Power in Wind equation

The Betz Limit is basically a theoretical number of the maximum efficiency you can possibly get. At most, only 59.3% of the kinetic wind energy can be used to spin the turbine and generate electricity. Remember this is a theoretical limit; in practice, you're going to be closer to 40%.

The Power in Wind equation is given as:

P = 1/2 x ρ x A x V³

Where:
P = power in Watts
ρ = air density (kg/m³, at about 1.2 at sea level)
A = Swept area of the blades (m²)
V = Velocity of the wind

So, no matter how good your turbine is, you will get in practice at most 40% of the wind energy converted to electricity. To capture the wind energy in the first place, you have two variables to increase (one in your control, the other not): swept area and wind velocity. The smaller you make the turbine, the faster you need to spin to make any meaningful energy. The only variable you control is the swept area, which means making the blades as big as possible. Also notice that the velocity is cubed in that equation, so you'll generate much, much less power at low wind speeds; don't assume this is linear or even exponential!

In other words, it doesn't work because physics.

Well, it's true the physics are what they are. My experience with small wind is that its overstated to say it doesn't work given a proper location with the right setup and expectations in line with reality. Mine is running fine, it benefits my system significantly when needed, and has been running for some time, but as I said it is only supplemental even here on the windswept plains.

 

[OzSolar]

Wind doesn't scale to small turbines. You're dealing with two fundamental issues:

- The Betz Limit
- The Power in Wind equation

The Betz Limit is basically a theoretical number of the maximum efficiency you can possibly get. At most, only 59.3% of the kinetic wind energy can be used to spin the turbine and generate electricity. Remember this is a theoretical limit; in practice, you're going to be closer to 40%.

The Power in Wind equation is given as:

P = 1/2 x ρ x A x V³

Where:
P = power in Watts
ρ = air density (kg/m³, at about 1.2 at sea level)
A = Swept area of the blades (m²)
V = Velocity of the wind

So, no matter how good your turbine is, you will get in practice at most 40% of the wind energy converted to electricity. To capture the wind energy in the first place, you have two variables to increase (one in your control, the other not): swept area and wind velocity. The smaller you make the turbine, the faster you need to spin to make any meaningful energy. The only variable you control is the swept area, which means making the blades as big as possible. Also notice that the velocity is cubed in that equation, so you'll generate much, much less power at low wind speeds; don't assume this is linear or even exponential!

In other words, it doesn't work because physics.

Back when modules were $4/watt we sold and installed around eight Bergey10kW turbines over the course of a 2 year period. Bergey had a stellar reputation which we eventually came to quite painfully learn was a total lie. Turns out no one really wants to admit that they got scammed out of at least $50k so the myth just continued unchecked.

What followed was a miserable experience for both us and the customer. We never used less than a 100' tall tower, often 120's. All of them were well sited by all the metrics. For performance predictions we used the most recent wind maps and Bergey's software which was very a fancy excel spread sheet that took all sorts of factors into account. It gave a very false sense of accuracy.

Cash flow calculations were carefully done for each project and they all were substantially more cost effective than solar. Keep in mind this was way back. We also took care to use pessimistic numbers. IE: if the maps said the average wind speed was "13.5 to 15 MPH" we would have used 13. As you mentioned since Velocity is cubed minor differences in wind speed radically change energy output.
https://diysolarforum.com/members/upnorthandpersonal.3879/report
The first turbine performed horribly from day one but because the folks at Bergey are masters of redirecting you to question your installation so we chased our tails looking from something we did wrong for over a year. 3 inverters failed at this installation due to assembly errors in the factory. So the circus went for over a year.

The turbine was supposed to average 1200 kWh's/month. We never got above 600 KWH and had many months below 100KWH. All of the turbines performed pretty much just miserably.

My summary is to stay away from small wind. Not only will they not produce enough energy to ever pay for themselves the won't even produce enough energy to pay for their maintenance costs.

 

[KellyDood]

Yes- do a search on 'best small wind turbines' then check all the prices/reviews on Amazon or wherever and they're all junk, or they've sold 2 of them.

I've given up on small wind for my house.

 

[OzSolar]

Yes- do a search on 'best small wind turbines' then check all the prices/reviews on Amazon or wherever and they're all junk, or they've sold 2 of them.

I've given up on small wind for my house.

If it's any consolation you're not the first person to give up on small wind, many have much more expensive stories than you.

I truly commend you for sharing your story, most people don't. I theorize that its embarrassing to admit you've been duped so the lies just continue. So many stories I could share.

Starting around 2004 for about 2 years I installed around 10 turbines, most of them in very good wind sites. All of them were "top of line" Bergey's, most were their flagship the American made 10kW and couple of the Chinese made 1KW. It took me about two years to wake up and realize it was never going to work. I too fell for all same lies told by the manufacturers. My reward was to spend the next ~10 years trying to keep those turbines going and it was a business nightmare. I'm literally getting chills thinking back to those dark days. It was seriously was bad times.

I've been in the renewable energy contracting business for 30 years and FWIW have NEVER seen a successful small wind story. I'm sure there's one out there but I've looked really hard. That just reminded me of a funny. A fellow contractor once told me "the only wind turbines that work are the ones that don't have monitoring". Lol. And he's exactly right!

Most never work, but many fail within a year and the few that make it 5 years or longer are about to need repairs that approach or exceed the cost of the turbine. For sure, the cost of those repairs is many time the value of the energy the turbine will ever produce.

I've talked to many piers as well owners of systems I didn't install and it's always the same story. It takes little prying because of the embarrassment factor but once they get comfortable with me the real story comes out. Everyone scratches their head for the first year or two assuming that they they've got a lemon or maybe there's something wrong with the install. Eventually everyone just gives up.

Be happy you made the decision sooner than later!

 

[KellyDood]

Oz,
I'm sorry to hear you went through all that.
It's easy to see how people get excited about renewables and see these package deals with solar & wind; I've almost grabbed that recently. You figure it must be legitimate when they're all over.
I started looking a decade ago for some low-resistance spinner like those on roof vents for my box truck, figuring I could use my driving energy to charge my deep cycle battery.
Guess we're all still lookin!

 

[OzSolar]

Oz,
I'm sorry to hear you went through all that.
It's easy to see how people get excited about renewables and see these package deals with solar & wind; I've almost grabbed that recently. You figure it must be legitimate when they're all over.
I started looking a decade ago for some low-resistance spinner like those on roof vents for my box truck, figuring I could use my driving energy to charge my deep cycle battery.
Guess we're all still lookin!

Thank you Kelly. Something about wind gets people to drop their guard and not ask the smart questions. I totally get it. VAWT's have gotten a lot of people and they are probably the worse. They don't work out of the box from day one.