Solar Panels for Grundfos 3 SQF 2

SystemSystem Posts: 2,511 admin
I am trying to price a system to pump water from a well 100 m deep, with the pump located at the 88 meter level.The static water level is at 67 m and the casing is galvanized steel,the pump that I am looking at is the 3 sqf 2 from grundfos.I have talked to the local Grundfos dealer and he is telling me that I need 21 solar panels each rated at 110 W to give me the required volume of water, which is 10 cubic meters of water in the summer months. I live in an area 35.25 degrees North and we have quiet a bit of sun , especially during the summer months(Southern Greek Island) . I dont see the need to provide 21x110w=2320 watts to a pump that is rated at 900W. If anyone out there can enlighten me I will appreciate it.


  • mike95490mike95490 Solar Expert Posts: 8,207 ✭✭✭✭✭
    Re: Solar Panels for Grundfos 3 SQF 2

    The panels rarely put out their rated watts, except for a very brief daily period in the 1 month they are aligned for. Also the warmer the air, the less efficient the panels become, that's why you need extra panels.

    What voltage is the pump rated at ?
    900W should be able to get away with 1800W of panels.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
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    gen: ,

  • System2System2 Posts: 6,290 admin
    Re: Solar Panels for Grundfos 3 SQF 2

    thanks for the reply Mike, if I were to get a tracker would the number of panels decrease significantly ie could it be cost effective.
  • Solar GuppySolar Guppy Solar Expert Posts: 1,959 ✭✭✭
    Re: Solar Panels for Grundfos 3 SQF 2

    For your needs the tracker would cost more than the panels that a tracker would save ... stick with the right number of panels and keep it simple.

    Go with what the dealer is telling you as they have the specific experiance to size the job right ... pumping water from 300 feet down is no small feat!
  • lukeylukey Registered Users Posts: 21
    Re: Solar Panels for Grundfos 3 SQF 2

    You may want to consider using the Kaneka G-SA060 thin-film amorphous panel. They have a voltage(max. power) of 67V which is double that of regular cristalline panels. They are also a helluva lot cheaper and work great in hot areas.
    There is a company in Arizona that specialises in water pumping using these particular panels. They are called SunPumps. I am not quite sure where in AZ they are located, but I met them at the Solar Power 2007 in Long Beach and their organisation seems to know what they are doing, and on top of that they are very nice people.

    I hope I did not cross any lines here mentioning a company name and if I did please remove this post. My apologies.

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