Kestral 800 watt

ws9876ws9876 Solar Expert Posts: 395 ✭✭✭
I didnt think this company had any affordable models but I see they lowered their
prices.. this 800 watt goes for 2200$.
Anybody have any experience with these??? The 600 watt is 1600$.


  • System2System2 Posts: 6,290 admin
    Re: Kestral 800 watt

    I might be able to help with this.

    Kestrel is a division of Eveready (the battery company) in South Africa, and distributed in the Americas by DC Power Systems. There are 4 current models in production; the 150, a 6 blade, fixed-pitch machine with a 5' rotor; the 220 - a variable-pitch machine with a 7' rotor; the 300 - a variable-pitch machine with a 10' rotor, and the 400 - is a 13' variable-pitch rotor unit rated 3,000 Watts.

    All Kestrels have polyphase axial-flux alternators that are rectified to DC at the machine. They have extremely low ripple on the output, which makes them work quite nicely in situations requiring very low EMF signal, and when used in conjunction with solar charge controllers, such as the MX 60, FM series OutBacks, the Xantrex XW and with the super-cool MidNite Wind Classic.

    Having said all this, they are not inexpensive turbines at all. When the product is very heavy-duty, marine grade, efficient in low and high winds and has built-in rotor speed control without having to yaw or shut down in high winds, they tend to not be cheap.

    While it is possible to build your own turbine that can (possibly) perform as well as the Kestrel, "most" people are not going to attempt such a project because of the time required, the skillsets needed and the impossibility of getting a one-off turbine through the rigorous new AWEA standards (similar to IEC 61400-2) for small turbines.

    So - I think that about covers it. ;-)
  • System2System2 Posts: 6,290 admin
    Re: Kestral 800 watt

    You gave a lot of info on the models, and the company, but you didn't mention the watt output except for the last, and largest one. Do you have output for the rest of these models?


  • Bob McGovernBob McGovern Solar Expert Posts: 25
    Re: Kestral 800 watt

    WS & Scott: The numbers for the Kestral 800 look about right for the swept area, tho way optimistic on the top end. They claim 80 kWh/mo (2.5/day) at 10mph; 125 kWh/mo (4.2/day) at 12 mph. Blade shape suggest high TSR, and the rated RPM of 1000 confirms it. It should spool up to 800W pretty quickly but flatten off as drag overtakes it. Connected to a small battery-charging system, I'd expect 3 kWh/day at 12mph. Could get noisy, at 1000 RPMs. Kestral info here.

    Kestral's 1000W model is a curious beastie. Its predicted outputs track the smaller Bergey XL1's very closely, though at 80 sqft swept area and higher rated RPMs you'd expect half again the production (the Bergey's numbers are optimistic). Somewhat alarmingly, the turbine begins governing at only 21 mph. This could be a design philosophy: skew the alternator toward low-wind production, get it up to charging voltage and max amps as fast as possible, then use blade pitching to hold it there; that's fine, and given the machine doesn't come with a controller, may be necessary in lieu of boost MMPT circuitry. OTOH, it might signal an alternator that is way too small for its blades, one that saturates early and runs fast and hot thereafter. That's not a good thing.

    Awaiting word from an engineer at DC Power Systems, the only North American Kestral dealer. They've put a 1000W unit in central Wyoming. Would like to chat with the owner. If it can survive there, I'm buying one!:D
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