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House water pressure pump

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  • House water pressure pump

    I'm looking for a recommendation on a pump to run my house occasionally off my cisterns. The home is off-grid solar so I'm looking for something energy efficient.

    I have a utility water feed with good pressure but its typically down or very low pressure 4-5 days out of the month and during storms it can be out for more than a week. I'd like to have something that I can keep on a switch so that its not drawing power and inline at all times and when it is used I don't want much power draw for the obvious reasons. We'd be using the water for typical household stuff, running a shower, washing dishes. I'd prefer not to use a submersible pump since I'd possibly be taking water either from rainwater cisterns (3 total) or a cistern I'll have filled from the utility water.

    I'm comfortable with the plumbing portion of this as far as switching around between sources - just not sure what kind of pump I should be looking at and if I should also be looking at a pressure tank.

    Last edited by cgofish; 08-19-2017, 09:11 PM.

  • #2
    If your flow requirements are low enough, a 12V pump for an RV or Boat. They build a little pressure and would work from cisterns..
    Powerfab top of pole PV mount (2) | 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



    • #3
      There are also, at a much higher power level, pumps that are designed to produce a constant pressure relatively independent of flow rate over a fairly wide rang of pressures. They do not require a pressure tank and more importantly they do not cycle on and off during water flow, so no frequent high power starting surge events.
      Not likely to be what you need, but of some interest to me.
      The most energy efficient and solar-friendly solution is to pump into an elevated tank with gravity discharge.
      SunnyBoy 3000 US, 18 BP Solar 175B panels.


      • #4
        As suggested the 12V or 24V pumps for boats/RVs will do the job, not a lot of volume though. The pressure tank is there to minimise cycling, and there are small ones available for them. For possibly similar pricing you will get an A/C pump that will give you more volume and better life span.

        Depends on your power availability.

        As suggested a gravity feed tank is best, I have mine at about 65ft and it gives me about 35psi, I have my pump set to auto fill it during the day.


        • #5
          Circling back to this. I have two stings of 8 batteries in my 48V bank with 2 Schneider Electric 6848 XW+ inverters and 2 Xantrex Solar Charge Controllers in my system.

          If I go with a 12V or 24V DC pump is it possible to connect those to a 48V battery bank or do I need to find a 48V pump like the Dankoff Flowlight (spendy for part time usage)?

          With the two strings of batteries can someone provide a brief description on how I would wire in a DC pump?

          I appreciate the help!


          • #6
            You can buy the same style pump in a 115 vac version. Here's one on eBay


            Harbor freight has a pretty nice larger one with built in pressure tank for a very reasonable price. [LEFT][COLOR=#333333][FONT="HelveticaNeueW01-57Cn"][SIZE=16px]Item #63407[/SIZE][/FONT][/COLOR][/LEFT]

            Last edited by littleharbor; 12-01-2017, 09:47 PM.
            2.2kw Suntech mono, Classic 200, NEW Trace SW4024


            • #7
              We have a full time off grid home with a 500' deep well. Currently we have a soft start Grundfos 5SQ-410 pump that runs at 6.6 gallons per minute into three pressure tanks for a total of 98 pressurize gallons . It takes just over 15 minutes of running to pressurize the house at 30/50# of pressure. The problem is the well pump comes on at night which really hammers our batteries. The current well pump draws 11.2 amps and shows about 2.5 kw while running. I'm thinking of going to a 1000 gallon cistern with a smaller pressure pump so that it can run at night if needed. I will have the solar to use the well pump during the day to pump into the cistern. By the way, our household uses 230-260 gallons of water per day and our elevation is 8,600'. The options I have are as follows: 1)I've found a Grundfos JP05D-CI jet pump that is 1/2 hp and is rated at 3.61 amps at 115v or 7.06 amps at 230v that pumps at 12.5 gallons per minute and uses about 770 watts while running. It is not a soft start pump but will pump up my 98 gallon pressurized tanks in just under 8 minutes which will save some power.
              Option 2) is a Grundfos scala2 "on demand" pressure pump that would not need the pressure tanks I currently have in place. It would power up every time you open a water valve or flush a toilet. This pump can be plugged into a 115v outlet and uses 5.7 amps and pumps at a rate of 13 gpm and uses about 550 watts while running. It has a variable smart control that "learns" your plumbing to control speed and power necessary to maintain a pressure you select up to 60#.
              So, my question is which of these two alternative would offer the least impact on the health of my battery bank? Or do you have a recommendation for a pump or setup that will reduce my battery usage in the evenings?
              Last edited by Mike90250; 12-30-2017, 08:50 PM. Reason: delink several links - Moderator