Newbie question - how to increase voltage to a pump

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KeithNyst
KeithNyst Registered Users Posts: 8 ✭
in Solar Water Pumping #1
Brand new, so ...
The grundfos SQF spec states decreased pump efficiency at lower volages (-20% at 35v, -10% at 60v),. If one powers the pump via dc from a 24 or 48volt battery bank, is there a device that can be used to increase the voltage sent to the pump to run the pump at higher voltage for higher efficienc (and smaller wire)?
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,439 admin
    #2
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    Re: Newbie question - how to increase voltage to a pump

    The standard way would be to use an AC inverter to 120 or even 240 VAC... Efficiency wise, it will just about be a wash (the pump is more efficient but the inverter has losses).

    However, it may save you a lot of money on wiring costs as you can use a much smaller gauge of wire at 120/240 VAC vs 24/48 VDC.

    If you were pumping to a cistern (daylight only pumping), you could drop the battery bank entirely for the well pump and just use several panels in series to obtain the higher voltage (or series/parallel, depending on the panel ratings and how much power you need).

    And use a simple/less expensive pump (plus pressure tank if desired) to pressurize your home/cabin/etc. when pumping from the cistern.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #3
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    Re: Newbie question - how to increase voltage to a pump

    No, the up-conversion process will waste as much as you save. Sorry.
    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 ||
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  • KeithNyst
    KeithNyst Registered Users Posts: 8 ✭
    #4
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    Re: Newbie question - how to increase voltage to a pump

    Thanks all,
    Given that, I think I'd opt for running an AC submersible that has a low initial surge vs. runnining DC. An SQFlex would provide option to go etiher way, but not sure it would be worth the extra $.
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  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    #5
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    Re: Newbie question - how to increase voltage to a pump

    It really pays to shop around, local and otherwise for both types of pump.. you may be surprised with the price differential. For me it is pretty small.

    Do you have an 'Irrigation' (think hay) specialist around? otherwise well specialists and general plumbing shops.
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
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  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    #6
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    Re: Newbie question - how to increase voltage to a pump

    I now that our host, NAWS has a voltage doubler from 12 to 24 vdc, and I suspect they have one for 24/48. I use one on a shurflo submersible to good effect.

    Tony
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  • solarvic
    solarvic Solar Expert Posts: 1,071 ✭✭✭✭
    #7
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    Re: Newbie question - how to increase voltage to a pump
    KeithNyst wrote: »
    Thanks all,
    Given that, I think I'd opt for running an AC submersible that has a low initial surge vs. runnining DC. An SQFlex would provide option to go etiher way, but not sure it would be worth the extra $.
    Why you yhomk you need a sq flex pump? A regular sq still has the low amp start up and can use a regular pressure switch. I see them in the price range of $650.00 for 1/2 hp 120 or 240 vac range.
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