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Dual Water Pumps To Prevent Flooding

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  • Dual Water Pumps To Prevent Flooding

    Hello all,

    I'm new to the solar world but have recently been acquiring equipment to build a simple setup to drain water from a pond in my backyard during heavy rainfall. The pond is close to the house and the basement even flooded on the previous owner.

    I purchased a cheap starter solar panel from Amazon, 5W 12V along with a charge controller and 2 small water pumps. I want to hook them up to a on/off switch (for now). Eventually I might look into a float switch or something to monitor water depth.

    My question is the battery. I have one 12V 5.0 A.H. battery that I pulled from a UPS. Will I need two or should I get a better battery?

    Pump specs: [COLOR=#494647][FONT=Arial][SIZE=12px]4.2W.Rated voltage: 12V DC.Max rated current: 350mA.Max flow rate: 4L/MIN

    Any help would be appreciated.

    Thank you.[/SIZE][/FONT][/COLOR]

  • #2
    Well a UPS type battery will not stand up to many cycles so while it may work in the beginning it will not last long trying to run 2 of those pumps.

    Also that 5 watt panel might have a hard time recharging even that small 5Ah battery. Whatever the max power current rating is of that panel you will need at least 1/10th the Ah rating of the battery you use. So ~ 0.5amps for a 5Ah battery and 1 amp for a 10Ah battery.


    • #3
      If the pond is close to the house, why wouldn't use power from the house if pumping is a viable solution? Is it a detention pond for a subdivision, a recreational pond only on your lot, is your plan to pump water into the street or your neighbors yard. I would consider grading or a french drain if your lot drainage is not what it should it be before moving water around.


      • #4
        You didn't say how long you would run the pumps. If you have 2 pumps, each are 4.5W, that's 9 watt hours (Wh) per hour running (2 x 4.5W x 1 hour). So if you are planning on running them for 12 hours a day, that's 2 x 4.5W x 12 hours = 108Wh). The 5W solar panel can produce, under ideal conditions, 5W x 1 hour x .6 losses = 3Wh per hour, probably max of 18Wh per day (5W x 6 hours x .6 losses). So that 5W panel can probably run the pumps for 2 hours a day, under ideal conditions.

        As for the battery, again, guessing about the hours you are running the pumps, 2 x .35A x 12 hours = 8.4Ah a day. You never want to use more than half of the stored power, so you'd need at least twice that, 16.8Ah. Plus I'm guessing the pond floods when it's raining, so you don't have sun to recharge it, so you need to store a few days worth, so x 3 days = 50.4Ah. The 5Ah battery you have can run the pumps for about 3.5 hours, and will die soon, as it is not designed for heavy daily use.
        Solar Queen
        altE Store


        • #5
          Thank you all for the input. I should be more specific.

          The pond is a small 4ft deep x 7ft diameter. It is simply a landscaping pond that we do not use at the time (new puppy). There is an empty field behind our house with a natural slope. Yes, I could possibly run an extension cord and use power from the house but I am interested in learning solar power and maybe eventually converting my shed.

          As far as run time. I only anticipate using it after heavy rainfall which could be 2 hours a week or even 24. Depends on the weather.

          I might need to purchase a panel with a higher rating. Here are the specs on the $20 panel I purchased:
          [B]Related power:5W[/B]
          [B]Short circuit current (Isc):0.3A[/B]
          [B]Working current (Iop):0.28A[/B]
          [B]Output Tolerance:±3%[/B]


          • #6
            Nice, well, that field behind you is probably the natural grade where the water was intended to go. I wouldn't see a scenario where the pond would increase risk of flooding due to surface water as it is likely downstream of your house. If the basement flooding was caused by water moving on the surface exceeding what the slopes away from your house can handle, it would be from all sides, but the water in the pond wouldn't actually move. Another culprit could be a subterranean perforated drain tied to your city sewer/drainage back flowing due to inadequate infrastructure, which could only be prevented by a valve in your main line-work often subsided by cities where this commonly occurs. Anyway, have fun by all means. You could maybe use the solar and pumps to do some kind of moving water feature operating daytime only.


            • #7
              I am slightly confused. The controller I purchased from Amazon is odd. When I blocked light to the solar panel the controller showed fully charged battery. When I let the sun hit the panel it showed low battery? Eventually when the sun went down it showed no battery LEDs on the controller.


              • #8
                A small pump, in heavy rain, to prevent basement flooding, is not a light undertaking. I would install a large pump, with a robust power source and discharge the water in a safe direction. A solar charged battery. in the rain, will not run the pump very long.

                Me, I would use a couple 6V batteries in series, and a marine bilge pump with internal float switch. Size the pump to insure the pond won't overflow. Run 120VAC out the yard to a sheltered NOCO battery charger to keep the battery charged. the 2 batteries should provide power for several hours/days if the AC fails.
                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



                • #9
                  French drain will be the best option to prevent flooding in your backyard during rainfall. You can get a better idea if you read this You can choose how far from your home you want to divert the water. So I think that this will be useful for you in the case of flooding. Hope you'll find it useful.