need advice on a new pump

System
System Posts: 2,511 admin
in Solar Water Pumping #1
I have been using a piston pump since 1998, which was recently refurbished when the brushes wore out. It lasted 2 weeks, then a spring that held the brushes in gave way and the pump stopped again.

I have a 48v DC system with wind/solar and battery storage (the usual off grid stuff)

I would like to change the pump to a more reliable pump.

water level...... 60-150 ft down, varies by season
top of well to storage tank........ 150 ft elevation
well depth, 340 ft
pump depth, now is 250 but can be any depth to 340
uses: residential, 2 adults, summer gardening
location: N Idaho
water: clear but with iron content from the basalt/granite

any advice? We are tired of having the pump pulled out all the time lately, and now it is on the fritz again.
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  • System2
    System2 Posts: 6,290 admin
    #2
    Re: need advice on a new pump

    I forgot to mention:

    flowrate: well only produces 1.5 GPM, so we have a 4000 gallon storage tank uphill from the house with gravity feed to the house.
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #3
    Re: need advice on a new pump

    So you are looking for a 48VDC pump, low flow, high lift ?
    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 ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

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  • System2
    System2 Posts: 6,290 admin
    #4
    Re: need advice on a new pump

    Perhaps I did not make the situation clear. My home is off grid, with a full 48v DC solar/wind system. The lighting and water pump are all wired 48v. The inverter is a single stage 110V, used to run appliances only. The pump is near to the house, and due to the valley location of the house, it is not practical to install another solar array, controller and etc.

    We are happy with the existing system of the pump controlled from the house DC electrical panel and the battery pack. I just need advice on which pump is better for this situation: another piston pump, centrifugal, or helical.
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #5
    Re: need advice on a new pump
    wcanevari wrote: »
    .. I just need advice on which pump is better for this situation: another piston pump, centrifugal, or helical.

    The wetted areas of the pump don't care about the driveing source. That choice is dependent on the water quality. If the piston has had no trouble with sand, grit or water quality, I'd stick with it.

    Motor brushes will ALWAYS be a maintainance issue.

    I think the SQ Flex series, can work with 48VDC.

    With pumps, there are so many variables and personal choices, you will have to become your own expert.

    In my case, I spent 4-6 months, collecting pump curve charts, measuring elevation to my storage tanks, and decided on a "generic 240VAC pump" because "all the pump guys know how to work and order parts" for it. As you are finding out, DC limits your choices, and parts may take weeks to get.

    My suggestion, look for a 1/3 or 1/2 hp, conventional 3 wire 120VAC pump (if your inverter is large enough to start it.) Set it deeper, so it can draw water from the well casing above it, and chose a low flow, high head model, so it does not run itself dry.

    Or the very fancy, expensive SQ flex series with low water cut-off.

    Regardless, you will have to study the pump curves to find the right model for you, not the one Joe Pump has had on the shelf for 4 years, waiting to dump on someone.

    The host of this forum has a listing for solar water pumps, I'd start there. And I'd avoid brushes, unless the pump is topside. (topside pumps can only suck up about 20' so they are out in your situation)
    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 ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #6
    Re: need advice on a new pump

    Mike is typing about Grundfos brand SQ series water pumps--Our host's water pumping page is here:

    www.solar-electric.com/sodcwapu.html

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Texas Wellman
    Texas Wellman Solar Expert Posts: 153 ✭✭
    #7
    Re: need advice on a new pump

    Grundfos supposedly likes the higher voltages better. They have a web-app on their site that you can play with all the variables and give it your info and it will give suggestions and tell you the output.
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  • PhilS
    PhilS Solar Expert Posts: 370 ✭✭✭
    #8
    Re: need advice on a new pump

    An SQ Flex pump was installed for us a couple of years ago.

    I find these pumps to be "magic"! Give it ANY voltage from 30 to 240, AC or DC, and it pumps (those numbers from memory but I'm close).

    It runs on 115V from an old Xantrex SW2512 inverter most of the time. I have noticed that it pumps faster when I power it from my generator and don't understand why (but there's LOTS I don't understand). I know this because I pump 200 gallons at a time and the time is different depending on the 115V source (on the generator is faster yet the voltage is lower, go figure).

    The "low water" sensor failed after a few months but I'm not having it pulled just for that. The Coyote brand low water sensor I'd installed decades ago only lasted a few years. I pump my 200 gallons then I know I've only got 20 to 40 left in the well.

    These pumps aren't cheap but I've never seen serious complaints about them.

    Phil
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  • Fe-Wood
    Fe-Wood Solar Expert Posts: 96 ✭✭
    #9
    Re: need advice on a new pump

    I use the grundfos SQflex and love it. My stats are similar to yours (OP) I have a float switch with gravity flow 4000 gl storage. I run the pump on 4 dedicated 135w panels. I put it in 6 years ago (I think). Only problem I've had was the connection for the float switch shorted so it wouldn't turn off. My "run dry" disconnect still works just fine. In the summer I use it for irrigation and domestic water so it works hard.

    I am completely satisfied
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