Axial Flux turbine at 10,000' with Clipper and Classic - setup questions

[ChrisOlson]

The tail on that turbine does not look right to me. It should be about 30 degrees off the side of the axis thru the mainshaft of the machine at rest. It looks to me like it's sticking straight out the back. That won't work. The machine will run about 30 degrees off the wind direction.

It's kinda hard to explain but the turbine creates a dead zone in back of it. It slows the wind. The offset of the head wins over the tail. The tail does not run straight with the wind like the feathers on an arrow. It has to be off the side so the constant wind pressure on one side the tail vane keeps the rotor facing the wind.

The kind of tail that I see in that photo will maybe work for a homebrew book design. But MPPT turbines make a lot more power and keeping them steered dead into the wind takes a really goofy looking tail setup.

I thought I might have a photo of this. You can see the anemometer pointer and that the rotor is dead into the wind. Pay no attention to them extra bars up there - those are for ham radio antennas. The main thing to note is the angle of the tail to get it to run with the rotor facing the wind.

I also think you have your offset of the head on the wrong side. Looking at the front of the machine, the yaw shaft should be on the left side. There's a reason for this, called torque and a phenomenon called gyroscopic precession. Looks to me like you built a self-furling machine.

[JW]

Hi Chris,

I am often trying to optimize the site here. When you/anybody uses end of post images there is an error that we have know idea how it works.. Me and TechAdmin have noticed this result. Its best to promote inline images instead of end of post images. I have gone back and fourth with Flavio to fix this problem. But we have been defeated. We have no idea to correct the bug.. All we can do is promote using inline images.

JW

[ChrisOlson]

OK, I know there is a tutorial on working with images. I'll have to review that and make sure to use inline.

When I saw the pictures of Chad's turbine it was the first time I've seen the layout of the machine. And it appears to me to be backwards and the tail is wrong on it. There is no way it can track the wind if what I'm seeing is what I think I'm seeing. The bearing on the yaw is not going to make any difference. The aerodynamics of the tail is wrong. And a spinning wind turbine rotor, especially on MPPT machine where is spinning quite fast, creates torque thru angular momentum. He has the direction of the torque applied thru angular momentum to the furling side with a RH turning rotor (looking from the front).

The other factor in facing the wind is that the mainshaft should be inclined by 6 degrees for clearance on lattice towers. This creates an undesirable situation that causes asymmetric disk loading of the rotor. It is a phenomenon called P-factor. The descending blade on the right side of the disc creates more lift than the ascending blade on the left side. This is due to the relative wind and the angle of attack of the descending airfoil being higher.

Of the two forces at work on the rotor - P-factor vs gyroscopic precession - the torque created thru angular momentum is far greater than the asymmetric loading of the disc since the 6 degree tilt of the rotor is not significant enough to cause a huge angle of attack difference, side to side. So looking at the machine from the front, the yaw shaft has to be on the left side of the mainshaft to overcome that torque force that will naturally furl the machine if the yawshaft is on the right side.

Combine all this with the design of the furling tail, and Chad's machine will track 45 degrees off the wind direction, unfortunately. In higher winds, say 20 mph, that furling tail being off the side by 30 degrees or so, will "wind up" and be sticking straight out the back. But this "wind up" of the tail exerts more anti-furling force to steer the head to overcome the thrust produced by the rotor being offset from the yaw to keep it steered dead into the wind to get maximum power from it. If it furls off the wind direction under load the rotor disc is now oblique to the relative wind, which reduces the effective swept area of the disc and you won't get the design 2.5 kW from the machine. It takes extreme wind, far beyond 30 mph, to get my design to furl at all. But that is one of the key reasons my machine makes so much power with an 11 ft rotor.

Furling, in the homebrew book designs, is to limit the machine so it doesn't burn up the generator. That is not a problem with MPPT. The machine would not have to furl at all, except for extreme wind storm protection. It takes 35 mph before it even attempts to start to furl. It takes 50-60 mph storm wind to get it to 45 degrees off the wind direction. The only reason it furls is to keep the rotor speed below 450 rpm, but it's producing 4+ kW at the shaft when that happens. And the side load on the tower approaches 1,000 lb-f laterally - an actual of around 860 lb-f of thrust when drag is factored. This is why the machine has to be built super heavy-duty. The trailer spindle randomly welded to a bunch of rusty salvage pipe won't take it.

So hope this helps to understand why my design was what it is. It is an engineered high-output design, the principle of operation of which is not covered in the homebrew books.

[bigrockcandymountain]

Wow , that gives me some things to think about. 
 
I carved new blades last winter and made them rotate opposite what they did.  I also adjusted my furling a bit when i mounted them.  It now furls way earlier.  The asymmetric thrust / gyroscopic precession.

Now to chad, my turbine still makes some power, and seing your tail is adjustable, yours will too.  I wouldn't go cutting it up just yet. 

Ok, so you go up there, take it down, and here is what you do. 

1.  Test the alternator with a big drill. 
2.  Add a bearing to the yaw. 
3.  I would mount the 9' blades but that is up to you.
4.   Put a ribbon on the tail or somewhere so you can see if you are running at an angle to the airflow.  Adjust your tail geometry accordingly. 
5.  Possibly add weight, or lengthen the tail to delay furling. 

That is what i would do.  Hopefully you get some other advice.  Mine might be worth what you paid for it. 

[wbuffetjr1]

Thanks everyone. I am going to get some stuff ordered. I'll be headed West in 2 weeks.

[wbuffetjr1]

I also have to say what a frustrating process!! Hopefully any future folks looking to buy an axial flux turbine can learn from my mistakes. I have wasted money and, more importantly, years trying to get an axial up and running. 

[ChrisOlson]

I also have to say what a frustrating process!! Hopefully any future folks looking to buy an axial flux turbine can learn from my mistakes. I have wasted money and, more importantly, years trying to get an axial up and running.

Actually, I don't know that the axial is a viable commercial design. A coreless generator is too expensive from a magnetic material standpoint. They are best as a DIY project, easier to build than a iron-core generator, but not usually cost-effective. Considering that since solar prices have come way down in the last 10 years, for the $10,000 cost in putting up a 2.5 kw wind turbine on a good tower, that cost can be recovered much more quickly with solar. When solar was $3/watt it was different. But when a 2.5 kW turbine makes 2,000 kWh/yr on a good wind site at 15 cents/kWh, it takes over 30 years for one to pay for itself. That same cost can be recovered in 5 years with solar at today's prices.

Even Bergey Wind realized the tipping point has been reached and they re-designed their machines to try to be competitive. But it remains to be seen if they can.

https://youtu.be/ZoeuX3iQUTc

[wbuffetjr1]

Actually, I don't know that the axial is a viable commercial design.

I 100% get that, but I suspect there will be other guys like me that want a turbine no matter what kind of financial sense it makes. There will also be other folks who fall into the trap with no idea of the financials. I know for a fact that the guy in CA has a few other folks on the hook already that have been waiting a LONG time. Maybe future buyers will see these posts when searching for axial flux turbines for sale.

[ChrisOlson]

Yes, I think wind turbines have a valid off-grid application. But I don't seem them being practical for grid-tie, and that includes the 2.5MW ones running in wind farms. Like 10 years ago the "experts" said wind power would supply 20% of the global electricity by 2020. It's still at the same roughly 3% that it was then.

The average home can install solar panels on its roof that can supply most of the energy needs for that home. And it doesn't look bad or make any noise, and lasts 25 years minimum. Wind power doesn't work that way. Most of 'em are wore out and torn down before they make enough energy to recover what was put into mining and manufacturing the raw materials to build it.

Despite the fact they aren't, and never will be, the answer to global energy needs they are still a valid off-grid energy source, or source for locations where solar doesn't work due to annual available sunshine.

[DamonHD]

Your numbers are stale, Chris.  Large turbine EROEI is typically well under a year these days and our current 10GW+ on the GB grid (and 18%+ of total GB generation last year) is not being replaced anything like annually.  I can link you to the relevant government and trade association databases if you wish...

Rgds

Damon

[ChrisOlson]

There's conflicting figures between wind power advocates like GWEC and AWEA and their government lobby vs the people that operate them. For one, the cost of infrastructure isn't factored except by the people that have to pay for it. Due to its variable nature, and the fact that where it's good to put a wind turbine there is no infrastructure, this all costs money and resources. The infrastructure has to be sized for peak wind production to make the turbine worthwhile. But the turbine only produces 24% of nameplate capacity in the real-world industry.

Cost in idle infrastructure to support it is never factored.

The fact that the machine produces WAY less than nameplate is not factored in the energy return on investment by the advocates.

The second problem is that wind power, unlike steam turbines or diesel peaking, can't be scheduled for peak load on the grid system.

The next problem is that the wind power lobby never factored the decommissioning and disposal costs, both environmental and financial, of the machines when they must be replaced. They are built of composites that can't be recycled. There is already landfills in Texas full of blades that have to be replaced as part of the maintenance life cycle when cracks are found during inspections. The decommissioning costs for the 50,000 or so turbines in the U.S. alone is  currently estimated at $12.3 billion by the companies that run them. Eventually it comes. They don't last forever. The ones that have been decommissioned so far have not lasted anywhere close to their predicted life cycle.

The bottom line, at least in the U.S., is that without federal subsidies the commercial wind power business is dead. Operators can't make any money with them without those subsidies. And we the taxpayer end up footing the bill both financially and environmentally. Nobody that lives near those wind farms likes 'em. They are an eyesore, they reduce property values, they are noisy, and people complain about shadow flicker when the sun shines thru the blades on their property.

This is what happens to many of them, and this is not widely advertised by the wind power lobby. But this turbine was put in in 2014. It's 20 miles from here, I don't remember what the nameplate capacity is.



It is dead on the tower. There is oil and grease streaked down the blades, it hasn't run since last winter. I was by there last Saturday and they got two big cranes set up and are tearing it down. The operator of it says it hasn't been profitable to run, it's not going to get fixed, they are going to scrap it. It was installed with federal subsidy money that I have to work to pay for.

This is how the wind power advocates bend reality



The actual output of that wind park is not even close 83MW with 11 Enercon turbines. It is approximately 1/4 of that. But that's not what they present in their rosy picture. They use installed capacity instead of actual production. So you can reduce the rosy numbers to 24% of what they claim, because inside the economics of operating one by the people that have to pay for it, that is the real numbers.

[DamonHD]

Chris, let's not divert this thread further.  Capacity factor and intermittency are well understood, and for example with UK offshore wind that capacity (or load) factor is getting up towards 50%; in 2016 (latest I can find) according to gov figures our nuclear capacity factor was 77% and none of it is demand callable either.  I support both technologies and think that they should both be in the mix, which ensures that I am unfashionable with almost everyone.

Rgds

Damon

[ChrisOlson]

Chris, let's not divert this thread further.  Capacity factor and intermittency are well understood, and for example with UK offshore wind that capacity (or load) factor is getting up towards 50%

Actually, it's 41%, but yeah offshore is better than on land. The problem with offshore is the impact on marine life, and the fact that it takes 5x more steel and concrete to put in an offshore turbine than it does one on land. They fail to mention that.   

Understood on the thread. Everybody that's interested in wind power should learn and be aware of the true limitations of it. And the fact that its capability is grossly over-stated, not only by residential wind turbine manufacturers, but by the wind lobby that gets public policy set as well.

[ChrisOlson]

Here's the figures on my turbine, the only one I have ever had with good logging for it.

The nameplate capacity is 21,900 kWh/yr.

If it matched the commercial wind industry figure of 24% nameplate it should produce 5,256 kWh/yr.

The best it has ever done was in 2017 - 2,001 kWh that year. Which is only 9% of nameplate capacity.

Over the long term in 7 years it has produced 7970 kWh, although it is inactive in the summer months most years. Nameplate would be 153,300 kWh in 7 years. It has produced only 5% of nameplate capacity over the long term. The roughly $11,000 that it cost to put it up would buy 582,010 kWh off the grid (10.89 cents/kWh in this area).

To produce the 7970 kWh it has made would take 2,344 hours of generator time with our Honda gas generator, which would burn 1,453 gallons of gas, which would cost $3,910 at today's prices.

So in summary it is roughly 3x more expensive to run than a gas generator over 7 years for off-grid power.

So for Chad, please realize the wind turbine is a fun toy. But it is not practical since the generator is way more reliable for standby power, better for the batteries (which are also not cheap), and way less hassles. These are some of the realizations I was coming to several years when I decided to exit the wind turbine business.

If we would've spent that $11,000 on more solar panels instead, go to all the work to keep them cleaned off the winter time so they work on cloudy days, based on my logging from solar over that same time we would've been better off. I get really mad at our solar in the winter because it doesn't work, and it's a lot of work to keep it working. But the logging shows even in the winter our 4.5 kW of solar capacity far outperforms the wind turbine in cost/kWh. I would've never believed it 7 years ago when I put the damn thing up. But I do now when I got hard data that proves it.

Solar was expensive then. You can get 280 watt panels for $179 now.

Just to throw out the realities of what to expect from a wind turbine. It's more of an off-grid status symbol than being practical.

[DamonHD]

I also like solar, and my last off-grid panels were about USD50/250W each IIRC.  If you're prepared to buy second-hand / remnants from big projects then (in full working order) solar is a decent workhorse.  B^>

Rgds

Damon

[kitestrings]

I find it interesting to see which things we want to see a payback on ;>].  The measure never seems to apply to the car, truck, trailer, boat, RV or side-by-side.  Anyway I like wind, small wind, somewhat out of fascination.  I've learned a lot being around it.

We've been off-grid since ~84-85 (and, I admit this has been by choice).  The main thing the wind does for us, is produce power in late fall, the winter, early spring.  We get a lot unfavorable solar weather in Nov/Dec.; we get a lot of snow, and I do clear the panels regularly.  It just doesn't cut it.

Our records are pretty spotty on the turbine.  We largely shut it down in the summer.  The solar works great thru most of the summer months.  In December our PV avg is less than 100 kWh/mo., and there are 8-10 day stretches with <.5 kWh/day. 

Our generator can fill this niche too, but not without noise, fuel, cost and maintenance.  If the turbine does even 4-6 kWh/day I'm pretty happy, and it seems to do that pretty easily.

[ChrisOlson]

It is the same here. The solar really starts to drop off in Nov. Dec is really bad. Then it starts to pick up again.

BUT - if I compare wind to cost of solar today, solar makes more sense. Just put in the capacity you need for cloudy days. Turn everything on during the sunny days and use it up. I've come to like solar power. My time would be better spent inventing an automatic snow removal device for the solar arrays with some sort of rotary brush on it, than it would be building more wind turbines.

Our generator can fill this niche too, but not without noise, fuel, cost and maintenance.

I tried several different generators, including a Generac EcoGen (which I don't recommend). I build a nice, pretty much sound-proof generator room that is well removed from the house. It is so quiet can barely hear it running standing outside the generator room. Can't hear it in the house even at night when everything is quiet. We got a 100 gallon tank outside the generator room for it that we refill maybe three times a year. And we have a fuel truck come to refill that. Next to the solar panels it is the most reliable and maintenance-free source of power we have.

Our system is set up different that most. Our inverter can handle 6kW continuous. It can handle like 7,200 watts for maybe an hour (depends on the ambient temperature). But if the inverter overloads it waits for one minute, starts the generator, syncs its sine wave with the genset, then loads the genset to its rated continuous power and the inverter fills in the difference. When the overload goes off, it continues to run the generator for five minutes (for cycling loads like my wife's electric range). If the load doesn't go over 6,000 watts in that five minutes it shuts the generator down.

This allows us to run really big intermittent loads without having to have a big battery bank and stacked inverters.

Xantrex perfected the art of generator support for off-grid power years ago with the SW-series inverters. But those had to be stacked for split-phase power. Our XW-series with native 120/240 split-phase does it better and allows us to run loads up to 10kW continuous while automatically managing the generator for least fuel burn. It was an integral part of our system when I designed it.

[JW]

The measure never seems to apply to the car, truck, trailer, boat, RV or side-by-side.  Anyway I like wind, small wind, somewhat out of fascination.

Chris  I think that you would not go well at a steam engine meet. Basically an the homemade of engines are 16 percent eff.

Although I would recommend you to work for NASA... too bad they went out of business.

[JW]

There is a spirit going on with my steam stuff. https://flashsteam.com/steam-engine-project-part-3
Just for the record were expecting 60eff.

I have 3 patents related to my steam machine...

When you re-use live steam in the engine without condensing it the eff is possible.

[ChrisOlson]

These Aermotor water pumpers have been around for 130 years. We had one on the farm when I was a kid. Me and my brother used to climb inside the tower and ride up and down on the lift rod. It was great fun.

They are not high speed but they create a lot of power in not much wind due to the solidity of the fan. They are not on high towers, 33 feet because the design is relatively immune to ground-caused turbulence of the wind flowing thru them. The one we used to ride up and down on was about 65 years old at the time because it said built in 1905 right on it. And it would turn and pump water in the slightest breeze. It even had an offset head with a furling tail on it.

And then electrical power generation came along and windmills suddenly had to have 3 blades and spin like an airplane propeller, needed high towers to work right, very sensitive to turbulence in the wind, all because electrical generators have to spin fast to work.

If you want interesting reading sometime for those cold winter days pick up a copy of Still Turning: A History of Aermotor Windmills by Christopher Gillis. There is thousands of these things scattered across the U.S. Still turning after a century. It is estimated there is 1,000 of them alone in the Navajo Nation. And they are still built today in Texas.

That's a practical application for windpower because it's a practical, durable, super heavy-duty design that has stood the test of time.

And amazingly they are efficient. The USDA Agricultural Research Service did a "study" comparing the old 8ft Aermotor to a modern electric water pumping system, both on 33 ft towers. The electric system used a Bergey 850 with a three-phase submersible pump. Both windmills pumping from a well depth of 100 feet. The Aermotor used the standard 2.75" cylinder with 7" stroke.

The old Aeromotor literally stomped the electric water pumper.

So then they said, ok - let's put the electric one on a 65 ft tower instead. The wind isn't good enough. The Aeromotor still stomped the electric one because it pumped water at 5 mph wind speed and it took 11 mph wind speed for the electric one to start making enough power to get the first drop of water. The electric one did beat the Aeromotor during two times of the year in Texas when it's really windy. But the Aeromotor being the slow reliable tortoise against the hare won the contest over a year's time.

It's all in the book.

So I'm not sure all the technology in wind power has really gotten us anywhere. Just made it more expensive, more complicated and less practical.

[ChrisOlson]

Oh, I bought up the old windmills because Chad had indicated in his email to me that he was trying to aerate a trout pond, I think it was. Look into the old Aermotors for a job like that. I know some have been converted to aeration units. And it is a design that works on short tower in low winds. Probably would work at 10,000 ft altitude where a conventional electric unit will be kinda weak.

IIRC the standard Aermotor 8ft runs at TSR 1 so in 5 mph wind it turns at about 18 rpm and makes 6 strokes per minute. I think their maximum pumping speed is 22 strokes/min, can't remember for sure without looking it up. I got one laying down in the woods in pieces that was taken down probably 40 years ago. Was always going to restore it but never got around to it. There's still a couple farms in this area that have 1920's vintage Aermotors pumping water for beef cattle.

[wbuffetjr1]

I actually started my aeration project 7 years ago with one air pumper. Then I added a second air pumper. Unfortunately they just don't make anywhere near the volume of air that I need for 7 acres of water. They also have trouble with condensation freezing up in the lines.

The solar system I have now runs a 1HP pump that is able to fully aerate the lake. My primary hope is the turbine fills in a few gaps in the Winter. My secondary hope for the turbine is I can get some supplemental aeration from it as a diversion load. If this diversion could happen at night that would be fantastic.

I am really leaning towards swapping in the 9' blades like BRCM suggested. Anyone see a downside to that??

[ChrisOlson]

The solar system I have now runs a 1HP pump that is able to fully aerate the lake. My primary hope is the turbine fills in a few gaps in the Winter.

I think you state a few key things
1) two air pumpers could not supply enough volume
2) the solar DOES supply enough power to run a 1hp motor (so far solar wins the contest)
3) fill in a few gaps in the winter

Wind turbines are hard on batteries. During periods of low solar radiation the batteries get discharged and sulfated. Wind turbines tend to sometimes meet the load but fail to actually charge the battery. So it can sit for days in a discharged state if solar doesn't come back, and the turbine "floats" it at a partial charge. This permanently damages your battery. It requires something with a steady output to actually absorb a FLA battery. Only solar or a combustion engine generator has that required output. And even solar can be variable if there's clouds intermittently blocking the sun on a partly cloudy day.

If you want to save the battery (which is the most expensive part of the system) use a good inverter/charger with a generator instead of relying on a wind turbine. Our system will start the generator if the system voltage does not reach 56 volts in 24 hours. It brings the battery to absorb (actually boost charges it with our XW-system by setting boost voltage to 60 volts for the first hour). After that first hour it then drops to normal absorb voltage of 58 volts and absorbs for 3.5 hours or 2.5% C current, which ever is reached first.

On solar it will run the full three-stage charge, with bulk, absorb (constant voltage - tapering current), float. On generator it uses a two-stage charge - bulk, absorb (for one hour at boost voltage), then shuts the generator down. This ensure the battery gasses and re-mixes the electrolyte.

On genset it does not fully charge the battery. But it returns it to high enough SoC to prevent hard sulfation. And an equalize cycle (done by the solar) every 30 cycles fixes any damage from incomplete charging.

The few dollars of fuel in the generator will save thousands in battery cost over the long term. A wind turbine will not "fill in the gaps" and save any money on batteries. All a wind turbine can do is offset the normal loads and help maintain the battery where it's at (hopefully > 90% SoC). With the size of battery used in most off-grid systems of any capacity it would take a really big turbine (like a Bergey Excel) to actually charge a battery, and even then they are too variable to do a decent job.

[wbuffetjr1]

I should clarify what I mean by "gaps" for my situation. The solar has kept my batteries in great shape over the last three Winters. Last year, record snow, we only hit the low voltage disconnect twice. I have the LVDC set very conservatively. I want to say 49 volts. IIRC, first time we were back to 100% charge in ~two days. Second time we were back to 100% in ~three days. During the Summers I am running the 1HP 8 hours per day and batteries rarely go below 97%. I am not running the 1HP pump near as long in the Winter as I am during the Summer.  The diversion load I have hooked up is a 1/2HP pump and is 100% bonus aeration. It puts out 4x the CFM of the air pumpers. If that pump runs for even 1 hour per day that would be fantastic. I THINK it could run for much more than that. I haven't done the $$ math at all, but I don't want to run a generator over the Winter to get that bonus aeration. We may go to our cabin for the week of Christmas, but other than that it is uninhabited from ~October to June. This lake Winter killed every year for 20 years. With the solar driven aeration fish have now survived two years in a row.

[ChrisOlson]

Ok, different story than an off-grid home then where there is 12kW/day and usually 16 kWh/day load in the winter. Like this time of year is normally good for us. But the battery got to 48 volts two days ago (under 1,500 watt load). The wind turbine and solar together couldn't get it above 52 volts yesterday at 70%SOC. And it is a repeat today.

Most off-grid installations have a fear of running the generator and the system will float the batteries at 48-52 volts for days at a time. Our generator started last night around 2:00AM and boosted the SOC to 90%. So today the battery is still floating at 52 volts today, just enough from solar (very little from wind) to hold the loads, but at 90% SOC instead of 70%.

It runs on a 24 hour cycle so if the battery never makes 58 volts today it will start the generator again, this time probably around 5:00AM tomorrow morning, and boost it to about 95% SOC for tomorrow.

We don't worry about "wasting" solar capacity if the genset starts and runs early in the morning. The system just kicks in water heating load to use it, since we've been using out the "bank" on hot water for two days now except for the three hours the generator ran last night.

Eventually, if you depend on just wind and solar, the 10 day to two week cloudy stretch of weather will "bite". Having the inverter hit low voltage disconnect is not an option here. Neither is floating the battery for two weeks @ 70% SOC, even though the system will do it, not making quite enough power to get thru the inefficiency of absorbing FLA batteries. Too hard on the battery.

I only know at this point that if we would've taken the money stuck into wind and put it in solar instead, the solar WOULD do the job and absorb the battery even on cloudy days, while giving us all the hot water we need on the side. The wind can't, and won't even on a windy day because it's not steady enough. It's in and out of absorb on a windy day, which is not the way to absorb FLA batteries. They need to be held at a constant voltage to de-sulfate properly.

[bigrockcandymountain]

My experience is a bit different than chris.  Probably because i have a different location, smaller bank, and a lower usage daily. 

Our bank is only 428ah 48v so it generally only takes 6 or 7 kwh to top it up.

Our daily usage is about 4kwh. We do have propane for heat, stove, water heating, clothes dryer.  We run basically without a generator.  We use one about 3 times a year.  It is a huge pain to set up when we need it. 

We are the sunniest place in canada and probably top 5 windiest, so that helps. 

All in all, i wouldn't be without wind.  It is almost always windy when it is cloudy here.  The turbine does a fine job of holding absorb voltage or so it seems.  Time will tell if our batteries are suffering.  We are only 4 years into this. 

Our turbine cost about $1000.  That is with a pile of work though.  And some free scrap iron. 

[ChrisOlson]

Yeah, our battery is 56 kWh, 28 kWh usable. But it's down to ~81% charging efficiency after 7 years. It held 92-93% charging efficiency for the first 6 years and really started to drop off this past year. So it's time for us to dump those batteries on somebody that can use them for an off-grid hunting cabin and get a fresh forklift battery or our generator usage will go way up this winter trying to keep them alive.

So if our battery is at 70% it takes 10kWh to charge them to float at their current efficiency level, plus another 12 kWh to meet loads for the day. Anything over 12kWh is usually high-draw loads like my wife's electric range, electric clothes dryer, or running my welder in the shop and those loads are always supplemented by generator power on Gen Support automatically, so they don't come out of the battery.

12 kWh is only average 500 watt load /hr. We don't have no propane - wife won't allow it. Just the fridge, freezer and furnace blower is 300 watts.

So the reality is that the solar will do this no problem, with plenty of extra capacity on a cold winter day. On the cloudy days if we'd stick in another 2,500 watts of solar vs 2,500 watts of wind turbine, the solar will kick the wind turbine's butt without even trying even running at 25% nameplate because it's steady power and not on and off the throttle, which is what the battery likes and is more efficient for charging. All the wind turbine does is surge charge at 1,600 watt one minute, and then the wind dies down, battery voltage drops, amps to the battery drops, and repeat. This not good for FLA battery, either charge the damn thing or discharge it. Don't turn the charger on and off every 3-4 minutes. All that does is hard-sulfate a battery, constantly cycling the same level of sulfation on the plates. I blame the wind turbine, and relying on it, for what I consider to be shorted life of our current battery because it's too easy to look at the monitor and it says 70%, and oh - that's good. It's not too deeply cycled and the wind turbine is holding it. We'll wait for the sunny day. Big mistake.

The cost of that solar today is only about $1,600 bucks. Can't even put up a decent wind turbine tower for that. When we put in our solar it would've been about $5,000 for an extra 2.5kW. Times have changed, price of solar has come down. Solar wins. And your battery will thank you for it 7 years later.

[ChrisOlson]

I blame the wind turbine, and relying on it, for what I consider to be shorted life of our current battery because it's too easy to look at the monitor and it says 70%, and oh - that's good. It's not too deeply cycled and the wind turbine is holding it. We'll wait for the sunny day. Big mistake.

Studying what changes we'd have to make to our system to put in one of these 3,000 lb forklift batteries for this winter, GB Industrial says don't opportunity charge your battery.

Scroll down to Over Charging and Opportunity Charging
https://gb-battery.com/faq

This is exactly what a wind turbine does is opportunity charge your battery. Constantly. It's better to have the capacity to charge it once a day. Then discharge it at night. And if it doesn't need to be charged the next day due to not being fully discharged, then set the Recharge Volts on the solar controller to not charge it and use the solar for water heating instead.

According to my calculations we will run 7 cycles a week in the winter for four months.***** The other 8 months of the year we will run 1-2 cycles a week if we put in the extra 2,500 watts of solar when we put in the new battery. I will hook up the wind turbine for three-phase water heating with the new battery, but I won't use it for battery charging any longer. I'll switch the Classic to that extra 2,500 watt solar array instead.

*****And I still have to clarify this with the GB Industrial guy. Because if they're talking 80% discharged - 20% SOC - then we will only run ~2.5 cycles a week in the winter. Because that is 45 kWh where our current battery can only deliver 28 kWh to 50%. And then we would have to put in more solar to properly charge it once it goes to a charge cycle because 45 kWh is serious amounts of power for one day on solar with charging efficiency at probably ~95%.

Whatever it takes, we will do. Solar is cheap (and reliable). And if the solar doesn't do it because of the cloudy day we'll use the genset to make it happy. We're not afraid to run the genset. It's an integral part of the whole system.

[wbuffetjr1]

So it's time for us to dump those batteries on somebody that can use them for an off-grid hunting cabin

Too bad you don't live closer to CO!

With everything above, about turbines being an inefficient choice versus solar or generator, being said.....

If I am trying to make lemonade out of my lemon....

Assuming I get things checked out/improved with my turbine.  (bearing installed on yaw tube, volts per rpm figured, bigger tail, etc)

 I am feeling like maybe installing the 9.2' blades would be a smart move for me. Yes, no?? If I think about it in terms of comparing to sea level, my 8.2' blades at 10,000' are equivalent to just shy of a 5' rotor at sea level. Could this be why I am having to set the cut in voltage so high before seeing any power at all?

[MagnetJuice]

If it was my turbine, I would install the 9.2' blades. You should be able to use your MPPT to balance things out. Or you might decide to adjust the air gap or add a little resistance to the line. Those are all methods that you can use to tune your system to do what you want with the kind of winds that you have. As a bonus, you will learn a lot about wind turbines, which I think you want to do anyway.

Any of those changes are going to affect when the turbine needs to furl. Because you have a telescoping tail, I would try to set the furling with the present tail. If that doesn't work, then you have the option to install a larger tail.

I hope that we can stay on topic so you can get your turbine working soon.

Ed

[SparWeb]

I'll add my vote for the 9.2' blades.

You might want to return the MPPT program back to a more conservative curve, then begin adjusting back again, just in case your adjustments with the current blades have moved the Classic's power curve too far to restrain the new blades.

[ChrisOlson]

Yes, definitely use the big rotor. That turbine was originally designed for a 10.8 or 11.5 ft rotor. The Classic used to have the curve pre-programmed in it from MidNite for the DWP320 turbine. It was in the memory's after the Bergey XL1 (I think), up around memory location 12-15 someplace in there.

The main thing is, don't over-estimate what a wind turbine can do. Even people familiar with them tend to hope for more than they get sometimes. To put things in perspective, even on the utility scale; it takes 200 of the largest offshore wind turbines that exist, with the wind blowing 25 mph, to equal the output of a single combined-cycle natural gas turbine generating unit operating at 75% load, and that fits in your machine shed.

The efficiency and capability of small wind is less than that of utility scale, when you scale it down to residential sizes. The average residential wind turbine does not produce enough power annually to power a 10.5 cu ft. refrigerator with a ice-maker in it if you use it for charging batteries, then convert back to AC with an inverter.

If you hook it up to bypass the loss stages - direct to a three-phase load (like a three-phase aeration pump) - you will get something more efficient. And even then it's pretty weak judging by tests the Ag Research Center has done on electric wind-powered water pumpers.

So the bigger it is, the better the chance it might power your toaster for a few minutes. There is no guarantee the wind will blow, and that it will work, when the sun doesn't shine on your solar panels. The only thing that provides a reliable guarantee for standby power is combustion engines.

This is all part of the learning curve with wind power and electrical power generation.

[ChrisOlson]

I had forgotten about one fault the Classic seems to have (sometimes). I have the wind turbine over-amp the Classic (it just happened this morning). Sometimes when it does this the aux fails to come on and completely unloads it in high wind. I came in for lunch and it was free-wheeling at around 200 volts. So I manually stopped it with the brake and then have to wait a few minutes until the Classic resets. It's flashing OVER AMP on the screen when it does that.

This is the 3'rd or 4th time I've had that happen in the last 7 years or so.