Classic, 1500 watts out of 10 footer. Video

[Volvo farmer]

This Classic works pretty darn well! It really wakes up my 10 foot Otherpower turbine. I have seen peaks of 2+ KW in 35 mph gusts. When I find a way to hold it back with a clipper, I'm gonna be a happy camper!

http://www.youtube.com/watch?v=7YjtmzUqgzs

[zap]

Nice... I like the sound when the mill speeds up.

And... very nice video of the greenhouse!!!  I didn't care for the music at first but it grew on my quickly.
Excellent... even though there were no old Volvos .

[ghurd]

Nice!
G-

[TomW]

VF;

Nice!

Bragging rights on high end outputs is cool and all but...

Does the device do anything in the more "normal" ranges for wind speeds?

I can't do video here due to can and string internet so if it is in the video I apologize for asking an already answered question.

Tom

[Volvo farmer]

Tom, I hear where you're coming from.  I have no way to quantitatively measure output at low and mid windspeed. I have a seat-of-the-pants opinion that I am seeing 50% increase in 10-20 mph winds, probably not much difference below 10mph.  Be advised that I have not measured anything, and I might be fudging my guess.

 I'm just getting my head around this, but it appears that I am running in a much more efficient TSR at most wind speeds. I think what is happening here is that before, I was below optimum TSR in a wide range of speed, especially with batteries at 24 volts.  I always saw more output out of my turbine with batteries at 28V, because the prop could spin faster before cut in. Now, the controller is happy to let the turbine spin away at 30-35V in low wind speed, and the result is that I get more power because the TSR is in a more efficient zone and the blades are working better.

[TomW]

That all makes sense.

As Chris has often noted overall power capture trumps max power peaks.

Thanks for the info on this ongoing development of MPPT for wind from the trenches.

Tom

[ChrisOlson]

Tom, I hear where you're coming from.  I have no way to quantitatively measure output at low and mid windspeed. I have a seat-of-the-pants opinion that I am seeing 50% increase in 10-20 mph winds

HI VF - that's very nice!

A simple, accurate and fairly cheap method to log kWh output of a wind turbine is a Doc Wattson with an external shunt.

I've gone to great pains to design my turbines for peak performance in the average wind speeds that they experience 95-98% of the time and forget about Max Dawg Balls Out power in the higher wind speeds that are intermittent and unpredictable.  I haven't gathered the courage (or the money) to try an MPPT controller yet to see if it actually makes a difference in kWh production on a properly designed and tuned turbine.  So watching your cutting edge experiment with interest here.

Thanks for sharing!
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Chris

[Boss]

Outstanding, really great to see a 10 footer put out like that. I'm sure it has been asked before, but please again if you have a ball park retail price for the Classic?
I too loved your Geodesic green house video and music. Way to go. Did you build that this Winter? Colorado, que no?
 

[Volvo farmer]

A simple, accurate and fairly cheap method to log kWh output of a wind turbine is a Doc Wattson with an external shunt.

I've gone to great pains to design my turbines for peak performance in the average wind speeds that they experience 95-98% of the time and forget about Max Dawg Balls Out power in the higher wind speeds that are intermittent and unpredictable.  I haven't gathered the courage (or the money) to try an MPPT controller yet to see if it actually makes a difference in kWh production on a properly designed and tuned turbine.  So watching your cutting edge experiment with interest here.

Thanks for sharing!
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Chris

And a really expensive, accurate and complicated way to track KWhr is with a Classic  

I understand your point that you want to harvest the most power in moderate winds, because batteries are full anyway in a real howler and the power is often wasted.  However, In my area, the winds are so variable, that I could never use one day's KWhr data and compare it to another's and get any sort of meaningful relationship. Heck I don't think I have seen two consecutive HOURS here where the wind has been exactly the same.

Outstanding, really great to see a 10 footer put out like that. I'm sure it has been asked before, but please again if you have a ball park retail price for the Classic?
I too loved your Geodesic green house video and music. Way to go. Did you build that this Winter? Colorado, que no?
  

$700.

Yes Colorado, We built it last fall. It's a nice place to take a nap in the hammock in February when it's 20F outside!

[Janne]

Hi,

The MPPT really helps most during moderate / high winds, when these axial flux machines are stalled the worst.

But as is the case with my homemade MPPT controller, it really also does help much on the medium winds scale, from about 3 to 6m/s. In my case with the 3.2m axial flux windmill, the optimal TSR of the rotor is somewhat higher than on the otherpowers design, as it is designed for TSR of 7. This led the rotor to stall in any winds much above 3m/s, and thus leading to a quite bad performance in the mid-wind scale.

With the MPPT controller however, the lowish efficiency of about 0.15 - 0.2 in the 3-6m/s region has now been increased to about 0.3 throughout the range.. The system still requires some fine tuning to the power curve, but even with just the calculated power curve, that is based on the available wind power from the rotor, the performance really has gone up significantly. So in my case it ended up being a good and cost efficient way of increasing efficiency in the mid-range wind output, while not sacrificing much on the low wind performance.. The low wind performance decrease mainly comes from the electrical (in)efficiency of the MPPT controller, being around 0.9 in the low power range.

About the video, it's really nice to see a 10 footer being running unhindered by stalling, outputting constant 1kW+ without the fear of a stator meltdown

[ChrisOlson]

And a really expensive, accurate and complicated way to track KWhr is with a Classic  

I understand your point that you want to harvest the most power in moderate winds, because batteries are full anyway in a real howler and the power is often wasted.  However, In my area, the winds are so variable, that I could never use one day's KWhr data and compare it to another's and get any sort of meaningful relationship. Heck I don't think I have seen two consecutive HOURS here where the wind has been exactly the same.

LOL!  Cool - I didn't realize the controller did that.

I don't generally find one day's data useful either.  I log long term and look at trends from month to month and compare last year's output data to this year's etc..  We live in a pretty good wind zone but our average is still only 12.1 mph.  So I've designed my turbines around that 12 mph average and have a pretty good handle on yearly kWh production at that average wind speed.  I'd love to try one of those MPPT controllers to see what it does for long term production, and experiment with gearing and the stator to arrive an an optimum configuration for MPPT that lets the turbine run at 100+ volts most of the time.  It was interesting to see your voltage limiter setup and that's one of the things I'm a little unsure about in experimenting with one.
--
Chris
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Chris

[kitestrings]

Vf,

Very cool.  Congrat's.  Thanks for sharng this, but tell me how do you make those blades stop and go backwards... 

All kidding aside, it sound pretty smooth thru the entire range of speeds.   I'm still thinking the leading edges are gunna need a bit more attention with MPPT, but a fair trade off for the gains made.

~kitestrings

[Boss]

$700.

Yes Colorado, We built it last fall. It's a nice place to take a nap in the hammock in February when it's 20F outside!

I like naps. I love green houses, Hmmm

I've been considering a partially buried green house with a small but deep rainwater catchment pool for food fish, probably just dreaming. Like I said I like naps; it's a good way to relax

[boB]

Volvo, thought this might be a good place to mention that I found a power curve graph anomaly that you might want to avoid...

When setting step 01 Amps, leave it at 0 Amps and try not to let steps 02 and step 01 Amps be equal.  i.e. leave at least
one Amp of space between them.... That is until I fix the code so that cannot happen unintentionally.

Better leave an Amp of space between the other steps as well, just in case.

boB

[Volvo farmer]

Thanks for the heads up! I am following you guys over on the Midnite forum almost daily so I saw the news there first.

Hit the 90A amp limit today on the Classic  Almost 3KW out of a 10 foot wind turbine... Quite impressive!

[ghurd]

Semi Off Topic:

I understand you were living quite comfortably the RE system before the Classic. 
Now there will be considerably more power available.

What impact will the Classic have on your day to day life?
Lower propane(?) bill?
Less time worrying about SoC?
Leave a incandescent porch light and CRT TV on all night?

The Classic seems like it would make a substantial impact on RE household power concepts and concerns.


Wondering if boB only invented it to cut into the sales of the ghurd controller? 
G-

[Volvo farmer]

Honestly, I'm not so sure it's going to make that much of a difference. I don't think low wind performance is improved all that much off where I had the turbine tuned before.  When it gets up and starts blowing, the batteries quickly get full and I'm dumping power. I'm just dumping more power now than I used to.

What I really need to do is to get myself an opportunity load, like heating water. 

If this thing was available when I did my installation, I would have wound the stator for a higher voltage and saved a bunch of money in copper down the tower and across the field.

[ChrisOlson]

Honestly, I'm not so sure it's going to make that much of a difference. I don't think low wind performance is improved all that much off where I had the turbine tuned before.  When it gets up and starts blowing, the batteries quickly get full and I'm dumping power. I'm just dumping more power now than I used to.

That's what I wanted to see - kWh @ 12 mph average.  Over the long term my machine makes 8.15 kWh @ 12 mph over 24 hours, with the rotor turning at a leisurely 136 rpm.  That 8.15 kWh @ 12 mph is the all-important number that powers my house day in and day out.  If a $700 controller could increase that number to 10 or 12 kWh then it might be worth it.  But I'm already at roughly 90% of what the rotor makes at the shaft @ 12 mph.  And yesterday when the wind blew decent here I got 21.72 kWh which is way more power than we can use.  Our water heater got up to 170 about 4:00 yesterday afternoon and the controller shut the turbine down because we had no place for the power to go.  And that's without a $700 controller. 

So I'm still trying to see how this pencils out to actually power an off-grid home day in and day out, except for bragging numbers in big winds which are useless.
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Chris

[halfcrazy]

Chris
I think the best explanation would be that if you have a turbine that is optimized for 6-8mph than at 12mph I suspect there would be an increase of say 25%?? If you designed a turbine similar to yours optimized for 12mph than you would not see a big gain at 12mph. I think the correct way to say it would be that it allows you to optimize for say 6mph and not stall at higher wind speeds. My 10ft machine used to start stalling around 10mph so I felt like at 12 I was gaining a fair amount maybe 25% give or take but at 15mph I was way ahead.

[ChrisOlson]

Well, see - this is what I was wondering.  Theoretically there might be some gains if I would wind a different stator that would let the machine operate at around 100 volts.  I don't know what the upper voltage limit of the Classic is, but I'm using 100 volts as a nice round figure because that would be easy to do.  At 100 volts and say 350 watts output @ 12 mph I'm only dealing with 3.5 amps down the tower instead of 12-13 amps on a 24 volt system.

I'm itching to try this because I think even at 12 mph there may be some gains by operating the turbine generator at higher voltages.  I've been sitting here watching VF's experience with it, and thinking about this, trying to convince myself that I need one.  LOL!
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Chris

[Flux]

I can't comment on the classic but I can add something about my experiments with mppt.

If you have the low end optimised for cut in at say 6mph you will almost certainly see a benefit in the mid wind range. If the machine doesn't have a low enough cut in then you probably won't. Normally things are chosen to run fast in the 8mph region to hold off stall in the 12 to 15mph region. You need a lower cut in for best results with the converter.

There is never going to be a massive improvement in the region below 20mph but it is worth having. It is always the case that a slightly larger prop will do more good for you in the lower winds, swept area means everything.

The other factor that decides whether or not the mppt is worthwhile is the local average wind speed. If you have a good wind area and you can get some sort of useful efficiency below 20mph then it may not be worth the cost unless you can alter your power use to use the higher winds when normally you may be dumping.

In our part of the world the average wind speed is very low and the number of days when things are dumping are limited. In these conditions any improvement in the 10 to 15mph region is very welcome and on the occasions when the wind is approaching 20mph you have far more energy input with the mppt and it certainly helps a great deal.

So it comes down to your local wind speed and your need for the very much higher output in the region above 20 mph. Some will find it incredibly useful when others will see little benefit.

Without accurate data logging you will not really be able to decide on the benefits in the lower winds but if set up right the benefit is considerable but there is always the fact that a larger swept area will do even more good. If you are stuck with a given turbine size then the mppt will be worth using, if you can go bigger then that will likely be a cheaper option.

If you can change your power usage to make better use of the winds above 20mph then it really does come into its own and it also takes away all the burn out issues that some seem to experience.

Chris you will benefit from generating at a higher voltage as you will have less transmission loss, you need this loss for direct connection but with mppt you can gain a lot here. I can't advise you on the limits of voltage on the classic or how it can be programmed but my own scheme is intended for cut in at 24v at 6 mph and runs up to over 80v. I did try it on 12v and it works well with the same alternator and the 12v line losses are similar to the 24v loss for the same cable so if you started generating at 50v your like loss would come down a lot.

Flux

[ChrisOlson]

Chris you will benefit from generating at a higher voltage as you will have less transmission loss, you need this loss for direct connection but with mppt you can gain a lot here. I can't advise you on the limits of voltage on the classic or how it can be programmed but my own scheme is intended for cut in at 24v at 6 mph and runs up to over 80v. I did try it on 12v and it works well with the same alternator and the 12v line losses are similar to the 24v loss for the same cable so if you started generating at 50v your like loss would come down a lot.

Flux, I have a stator for my 12G geared turbines that runs at 148 open volts @ 5.7 TSR and 25 mph wind speed (325 rotor rpm).  I've looked at using this stator with a Classic on a 24 volt system, with the generator stator running at 100-120 volts (loaded volts).  But the Classic does not have enough capacity to handle the 152 amp output on a 24 volt system without stacking them, and then the cost gets prohibitive.  As it is these machines push 140-145 amps @ 28 volts in high winds with the rotor running at 4 TSR with no MPPT.  So I'm afraid there would be a lot of impressive smoke if the wind really picked up.

And there's the issue of too much power for the battery bank and auxiliary loads.  140 amps is already past the reasonable limits for a battery charging turbine.  Batteries charge best at 10% of their amp-hour capacity for bulk charging, and trying to design an auxiliary loading system to handle the extra power to keep the battery charging rates within reasonable limits is hard to do when you're dealing with a machine that puts out from zero to 140 amps.  And you have no control over it because you have no control over the wind.

Being I like to experiment with things I'd like to try it, and see if I could regulate the turbine enough in high wind speeds to prevent damage to the MPPT controller while still realizing an increase in output at 12 mph.  I've tuned the machines to run at 5.7 TSR @ 12 mph, which yields 328 watts into the batteries.  I've tried all sorts of different configurations of gearing, stators and line resistance, and just simply can't seem to break that 328 watt barrier with a 3.75 meter turbine.  So that would be my only interest in trying MPPT - to see if there's enough gains at 12 mph wind speed to justify the cost.
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Chris