Axial Flux, Classic, Clipper & Diversion ?s

Wbuffetjr1Wbuffetjr1 Registered Users Posts: 86 ✭✭
edited March 17 in Wind Power Generation #1

Hey folks

My site is at 10,000' in the mountains in Colorado. We get some really good wind. I have an off grid solar system in place now. 48V battery bank, Classic 200, Magnum 4448PAE inverter. This Summer I will be adding an Axial Flux turbine to the mix (15 coils, 70 turns each coil, 8.2' blade set, ~40' tower). The turbine stator can be setup for 24V, 48V or 64V. Trying to decide whether to run it at 48V or 64V. Any advice? 

I am not an expert at this stuff. Still learning tons. I am having a hard time wrapping my brain around which classic to run the turbine with. I already own a brand new Classic 250 that I would like to use to save some money. Planning on purchasing the Midnite 4,000 watt AC clipper. Does anyone see any issues with this setup? Would the classic 200 be a better fit? I want to have plenty of headroom but I will probably set the clipper and classic up pretty conservatively. It is a remote site and long periods without someone there. I would like the turbine and electronics to have a long healthy life. This ties back to my first question. Hard for me to nail down the best combination of stator voltage and classic sizing. 

Next part, in addition to powering our cabin during family visits, I currently run a 1HP pump up there for aeration in our trout lake. The 1HP pump is controlled be a timer. Spring, Summer and Fall the solar runs the pump pretty much no problems. In Winters with lots of snow, like this year, I could use some more power up there hence the Axial Flux. Winter is also when we have our best winds. I think the turbine will make a lot more power than I will need and I would rather not waste it all. I would like to set up a 1/2HP pump (for extra bonus hours of aeration) as a diversion load for the system. Only problem is the 1/2HP pump CANNOT run while the 1HP pump is running - the clipper would just have to clip. I was thinking run power to another timer to control the 1/2HP pump then have a relay between the timer and pump that could be turned on with one of the various Classic "diversion functions". I am sure that is a Caveman solution and you guys can suggest something far more elegant!! I currently have the whizbang running on the solar classic. 

I am totally open to suggestions. Please treat me like you are talking to a ten year old child :P. 



  • Ralph DayRalph Day Solar Expert Posts: 888 ✭✭✭✭

    I have a Bergey XL1 with Midnitesolar 250 Classic, and a Clipper. It works very well, you have a pot to adjust clipping voltage in the Clipper...from 0-250volts. I once set mine to zero when i was gone for 6 weeks travelling. The Classic gives great control over the Clipper too.

    I liked the Classic so much I bought another one for my solar input too.


  • Wbuffetjr1Wbuffetjr1 Registered Users Posts: 86 ✭✭

    Thanks for the input Ralph! I am assuming your XL1 is a 48V?? What do you normally set the volts to clip at?? Have you ever had the 250 over amp?

  • Ralph DayRalph Day Solar Expert Posts: 888 ✭✭✭✭

    I keep the Classic clipper control max voltage at about 150v, the Clipper itself (pot) at 200. It's never gone over amps, but the 1kw turbine has provided over 2kw in a big gust...probably 110-120km/hr gust (70mph or so). that would be just before it would divert. Divert or dump wind is when the turbine head is driven up and back (pivots on the yaw bearing) to dump wind.


  • Wbuffetjr1Wbuffetjr1 Registered Users Posts: 86 ✭✭

    Thanks for the info Ralph! Are you on 24V or 48V?

    Do you use any of the diversion/dump functions off of the Classic?

  • BB.BB. Super Moderators, Administrators Posts: 29,641 admin
    edited March 21 #6


    I really do not have anything much to add--This is way out of my experience.

    In general, you need to pick your winding voltage to match the classic controller you will be using. Running a higher voltage from the turbine to the battery shed--Allows smaller gauge wiring and farther distances from shed to turbine--And you will generally want the turbine to be pretty far from any home/occupied buildings/children play areas. Both for noise and incase anything fails (hub, bladed, yaw bearings, etc.).

    The MPPT Classic does a great job with wind turbines because it can run a much higher voltage from the turbine to the controller. It pulls less current to let the turbine spin faster and develop more voltage (power=Voltage*Current) and therefore more power.

    The drawback with higher input voltage is that the Classics have a derated output current (high voltage FETs, generally have higher resistance).

    boB from Midnite does come by here for a visit once in a while--But you may get faster/better help by going directly to Midnite's forum:

    You will be talking directly with the designers and manufacturers of the Classic/Clipper system.

    Knowing your current/voltage/RPM profile, and maximum RPM will of your design will help a lot.

    Also having, at least, several methods of shutdown (Clipper load, feathering, furling, mechanical brake, etc.) will be important too. You need your system to be pretty much fail safe. And just using a single method (like the clipper load/high current dump from alternator to "stall" the blades") is usually not enough.

    Otherwise, a few links that may help: (good forum for DIY Wind Power)

    Hugh Piggott - Scoraig Wind Electric site for tons of info (from mike90045)

    Scoraig Wind "Recipe Book" for DYI Turbines (from Chris Olson... From his 4/11/2013 post) (added from "russ"--Like here but more wind/less solar)

    And, there is asking questions from your retailer for the Clipper system... Of course, our host Arizona Wind & Sun, would be a good start too:

    If anyone here has helpful information for Wjr, please feel to chime in here.



    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Ralph DayRalph Day Solar Expert Posts: 888 ✭✭✭✭

    Hi again

    I am at 48vdc system. I do use the aux functions off the classic...aux 2 is the Clipper control, aux 1 is to a relayed house voltage outlet. The solar clipper also runs 2 relayed outlets, one for a small fan that blows on the controller itself and one for a dump load.

    Either classic can run the oil filled heater or the water distiller, it's just a question of moving the load from one outlet to another (they're side by side). I run them on Float Hi right now, but they'res lots of modes to choose from.


  • Wbuffetjr1Wbuffetjr1 Registered Users Posts: 86 ✭✭

    Thanks for all the info and suggestions BB and Ralph! I have been emailing back and forth with Ryan at Midnite. He knows the axial turbine well and has been VERY helpful!

Sign In or Register to comment.