DC or AC well pump

Farmerboyz1721
Farmerboyz1721 Registered Users Posts: 39 ✭✭
in Off Grid Solar & Battery Systems #1
Pro's and Con's of AC versus DC submersible well pump.

The application will be a well depth of about 450' and a goal of 15 GPM into a holding tank. 


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  • jonr
    jonr Solar Expert Posts: 1,386 ✭✭✭✭
    #2
    Primary advantage of DC (or 3 phase AC + VFD)  is the lack of start-up surge.

    I am available for custom hardware/firmware development

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  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    #3
    You need high voltage for that distance.  It's usually easier to use AC when you have high voltage.   What will be the source of power?  Are you thinking of connecting solar panels to the pump without batteries or inverter?

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
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  • Farmerboyz1721
    Farmerboyz1721 Registered Users Posts: 39 ✭✭
    #4
    The power source will be solar direct to the pump. Pump the water into a holding tank when the sun is out.  Then have another smaller inline pump that will give the house pressure. 
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  • jonr
    jonr Solar Expert Posts: 1,386 ✭✭✭✭
    edited September 2016 #5
    For solar direct to the pump, you need a pump/electronics designed for that.    And I doubt that 450' @ 15 GPM exists with that.

    For less GPM (5.6, more in line with household use), there is the Grundfos 6 SQF-3.

    https://www.solar-electric.com/grundfos-sqflex-6-sqf-3-solar-pump.html?gclid=CLCQ17y76c4CFQKsaQod4WcGHQ

    I am available for custom hardware/firmware development

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  • Anawa
    Anawa Solar Expert Posts: 225 ✭✭✭
    #6
    Grundfos SQF may have a pump capable of delivering 15 GPM at the depths you have. My SQF delivers 11 GPM consistently without any hiccups. I can fill 3k gallon tanks in a few hours with good sun. Direct PV-to-pump through controller. Very stable system. Total wire run from controller to pump is about 500+ feet, 10 gauge copper wire.

    Is your well capable of delivering 15 GPM?

    Paul
    in Georgia
    Paul 
    in Georgia

    System 1: PV- 410w Evergreen, Mppt- Blue Sky Solar Boost, Batt - 225ah Deka AGM, 12v led house lighting,
    System 2: PV- 215w Kyocera, PWM - Morningstar PS30, Batt- 225ah Deka GC's, 12v led house lighting, Dankoff 12v water pump,
    System 3: PV- 1.5kw Kyocera, Grundfos 11 SQF well pump, 3000 gal above ground water storage, dom water & irrigation,
    System 4: PV- 6.1kw Kyocera, Mppt- Outback FM80-2ea, Inverter- Outback FX3648-2ea, Batt- 804ah GB traction, Grundfos BMQE booster pump 240v, Mitsibushi mini-splits 240v, 18k and 15k
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  • Farmerboyz1721
    Farmerboyz1721 Registered Users Posts: 39 ✭✭
    #7
    @Anawa do you have a model number so i can look it up?
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  • Anawa
    Anawa Solar Expert Posts: 225 ✭✭✭
    #8
    Here is a link to the Grundfos product line. I have the SQF11-2. The literature is comprehensive, so you should be able to make a judgement whether or not this pump will work for your application.

    http://us.grundfos.com/products/find-product/sqflex/_jcr_content/tabbedpanel/brochures/download_list/downloads/download_0/file/file.res/L-SP-TL-014.pdf

    Good luck.

    Paul
    in Georgia
    Paul 
    in Georgia

    System 1: PV- 410w Evergreen, Mppt- Blue Sky Solar Boost, Batt - 225ah Deka AGM, 12v led house lighting,
    System 2: PV- 215w Kyocera, PWM - Morningstar PS30, Batt- 225ah Deka GC's, 12v led house lighting, Dankoff 12v water pump,
    System 3: PV- 1.5kw Kyocera, Grundfos 11 SQF well pump, 3000 gal above ground water storage, dom water & irrigation,
    System 4: PV- 6.1kw Kyocera, Mppt- Outback FM80-2ea, Inverter- Outback FX3648-2ea, Batt- 804ah GB traction, Grundfos BMQE booster pump 240v, Mitsibushi mini-splits 240v, 18k and 15k
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  • Anawa
    Anawa Solar Expert Posts: 225 ✭✭✭
    #9
    BTW, the Grundfos SQF line of pumps responds directly to your original post... it operates on either AC or DC. So, I guess, if you start out DC and later down the line you switch to AC (for whatever reasons you should decide to do that) you're still good-to-go with the SQF.

    just saying....

    Paul
    in Georgia
    Paul 
    in Georgia

    System 1: PV- 410w Evergreen, Mppt- Blue Sky Solar Boost, Batt - 225ah Deka AGM, 12v led house lighting,
    System 2: PV- 215w Kyocera, PWM - Morningstar PS30, Batt- 225ah Deka GC's, 12v led house lighting, Dankoff 12v water pump,
    System 3: PV- 1.5kw Kyocera, Grundfos 11 SQF well pump, 3000 gal above ground water storage, dom water & irrigation,
    System 4: PV- 6.1kw Kyocera, Mppt- Outback FM80-2ea, Inverter- Outback FX3648-2ea, Batt- 804ah GB traction, Grundfos BMQE booster pump 240v, Mitsibushi mini-splits 240v, 18k and 15k
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  • Mangas
    Mangas Solar Expert Posts: 547 ✭✭✭✭
    edited September 2016 #10
    On one well, I have a Grundfos 6 SQFlex-3 AC/DC pump set at about 310 feet.  This model has an excellent extended depth max head capability.

    I believe there are 11 SQFlex pumps to choose from.  Grundfos has always been my  preference.
    Ranch Off Grid System & Custom Home: 2 x pair stacked Schneider XW 5548+ Plus inverters (4), 2 x Schneider MPPT 80-600 Charge Controllers, 2 Xanbus AGS Generator Start and Air Extraction System Controllers, 64 Trojan L16 REB 6v 375 AH Flooded Cel Batteries w/Water Miser Caps, 44 x 185 Sharp Solar Panels, Cummins Onan RS20 KW Propane Water Cooled Genset, ICF Custom House Construction, all appliances, Central A/C, 2 x High Efficiency Variable Speed three ton Central A/C 220v compressors, 2 x Propane furnaces, 2 x Variable Speed Air Handlers, 2 x HD WiFi HVAC Zoned System Controllers
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  • Lyle
    Lyle Registered Users Posts: 1 ✭
    #11
    Be advised that the Grundfos SQF pumps are warrantied for 24 months from install, not to exceed 30 months from date of manufacture. Of the two 6 SQF-3 pumps I have seen, one failed  at about 3 years for a bad motor (internal controlled burned up) and the other failed at 5 years for a broken rotor shaft (1/2" stainless steel shaft) in the motor. Both pumps were pumping from 540' and powered directly from 200VDC solar. How much do you want to put in the bank every month to replace pumps?
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  • jonr
    jonr Solar Expert Posts: 1,386 ✭✭✭✭
    #12
    Interesting.  I wonder if there is some advantage to reducing load on the pump by restricting the power input.  Eg, connect only 500 watts of panels to it (vs 900+W for full output).

    I am available for custom hardware/firmware development

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