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  • solar panel pool pump help

    hi guys i'm new to the forum and have been looking around the web for an answer to my question. I have a 16 x 32 in ground pool, i recently bought a 4 x 20 solar pool heater for it, now i don't want to plum this in to my existing pump, ideally i would like to run a seperate 12 volt pump that is directly connected to solar panels, i can do the math and get a panel to run the pump but i don't know if i should get one that has a 15 foot lift capacity, as that is how high the roof is. also i don't know what king of gpm i should be looking at. please help.

  • #2
    Unless you live on the equator the panel you bought will not do much for you heating wise. (and if you do you wouldn't need it any way)
    General rule of thumb if you live in the US is 50% of surface area of the pool if in full sun and a proportional amount more if partially or completely shaded.
    The minimum flow requirements should be specified by the manufacturer of the panel. Hint you do not want hot water coming out of the panel perhaps a degree or two warmer. Low flow although it will produce hotter water will not put nearly as much heat (BTU's) into the pool as a much higher flow at a lower temperature rise.
    NABCEP certified Technical Sales Professional

    [URL="http://www.solarpaneltalk.com/showthread.php?5334-Solar-Off-Grid-Battery-Design"]http://www.solarpaneltalk.com/showth...Battery-Design[/URL]

    [URL]http://www.calculator.net/voltage-drop-calculator.html[/URL] (Voltage drop Calculator among others)

    [URL="http://www.gaisma.com"]www.gaisma.com[/URL]

    Comment


    • #3
      Originally posted by Naptown View Post
      Unless you live on the equator the panel you bought will not do much for you heating wise. (and if you do you wouldn't need it any way)
      General rule of thumb if you live in the US is 50% of surface area of the pool if in full sun and a proportional amount more if partially or completely shaded.
      The minimum flow requirements should be specified by the manufacturer of the panel. Hint you do not want hot water coming out of the panel perhaps a degree or two warmer. Low flow although it will produce hotter water will not put nearly as much heat (BTU's) into the pool as a much higher flow at a lower temperature rise.

      i understand that one panel isn't going to do much, but its all i could afford at the moment, i plan on adding more, the main question was, what the pump should be rated for as far as lift, and if anyone has any good websites as to where i can buy a 12 volt version.

      Comment


      • #4
        How high above the pool, will the panel be located ? Will it drain back when the sun is not shining ?
        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

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

        Comment


        • #5
          Originally posted by Mike90250 View Post
          How high above the pool, will the panel be located ? Will it drain back when the sun is not shining ?
          the panel is 15 feet above the pool, i want some kind of pump that i can just throw in the pool and connect with pipes to the panel. the other end of the panel is connected to a pipe that just sits in the pool as a return, they are both submerged. I live in california so freezing isn't a concern. i assume the water will drain back down from the panel but i am not sure.

          Comment


          • #6
            You have to do something at night, or the warm pool water rises up to the panel, cools off, and goes back down into the pool. So a system that drains itself at night (or when the sun goes down) would be useful. So you have to pump the 15-20' of head, and have an air gap or something at the return, so the siphon will break.
            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

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

            Comment


            • #7
              Originally posted by Mike90250 View Post
              You have to do something at night, or the warm pool water rises up to the panel, cools off, and goes back down into the pool. So a system that drains itself at night (or when the sun goes down) would be useful. So you have to pump the 15-20' of head, and have an air gap or something at the return, so the siphon will break.
              so any good recomendations for a 12 volt pump that i can run from solar panels?

              Comment


              • #8
                May I jump in with a related question? When wiring a pump directly to a solar panel, are there any special considerations, like fusing or other wiring that should be kept in mind. Would a resistor or voltage regualtor help the pump run better? I will be experimenting with this for a few different projects this year so any input would be appreciated.

                Comment


                • #9
                  Originally posted by green View Post
                  May I jump in with a related question? When wiring a pump directly to a solar panel, are there any special considerations, like fusing or other wiring that should be kept in mind. Would a resistor or voltage regualtor help the pump run better? I will be experimenting with this for a few different projects this year so any input would be appreciated.
                  fuses are always helpfull to protect yourself and the pump, as far as wiring, without knowing a bit about the pump specs its imposible to tell. forget about resistors for pump speed control, use a pwm circuit there are lots on the web and they are easy to make.

                  Comment


                  • #10
                    Originally posted by green View Post
                    May I jump in with a related question? When wiring a pump directly to a solar panel, are there any special considerations, like fusing or other wiring that should be kept in mind. Would a resistor or voltage regualtor help the pump run better? I will be experimenting with this for a few different projects this year so any input would be appreciated.
                    Usually when trying to mate up a solar panel almost directly with a pump (no batteries at least) you need to look at how the panel and the pump work:

                    For a given amount of sunlight, the panel will be close to a constant current source. That is no matter how far down the pump pulls the voltage, the current will not increase enough to give the pump more power. The pump, on the other hand, will try to pull more current as the voltage goes down to deliver the same load. So you have to really decrease the voltage and increase the current but by a smaller factor to get the pump to do its best.

                    Here is an example with made up numbers:

                    Panel in full sun gives you 20 volts Vmp and 15 amps Imp. That is a 300 watt panel.
                    But in half the sunlight, you get 20 volts Vmp and 7.5 amps Imp. Delivering 150 watts.

                    Let's say that the pump would like to run on 24 volts, 10 amps for maximum output.
                    With full sun on the panel, it would be OK, drawing maybe 12 amps since the voltage is only 20 volts, and it would deliver close to full output.

                    With half sun on the panel, the pump would try to draw 12 amps but could not. The voltage at which the pump will draw only 7.5 amps may be as low as 10 volts.
                    Since the panel is a current source, it will deliver 7.5 amps at 10 volts, for only 75 watts getting to the pump.

                    A device called a linear current booster will go between the panel and the pump and convert that 20 volts at 7.5 amps to 15 volts at 10 amps and both the pump and the panel will be delivering the most output they can for that amount of sunlight.
                    This is somewhat simplified, but still should show you why a Linear Current Booster is important if you want the pump to deliver as well as possible on cloudy days and for more than just the two hour period centered on solar noon.
                    SunnyBoy 3000 US, 18 BP Solar 175B panels.

                    Comment


                    • #11
                      to run a common brushed motor directly from a PV panel, you need a Linear Current Booster. It's sort of a voltage regulator and a capacitor. It keeps a pump from burning up when stalled at low light levels.

                      FAQ
                      http://www.sunshineworks.com/linear-...t-boosters.htm
                      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

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

                      Comment


                      • #12
                        Originally posted by Mike90250 View Post
                        to run a common brushed motor directly from a PV panel, you need a Linear Current Booster. It's sort of a voltage regulator and a capacitor. It keeps a pump from burning up when stalled at low light levels.

                        FAQ
                        http://www.sunshineworks.com/linear-...t-boosters.htm
                        is this the same as MPPT?

                        Comment


                        • #13
                          Originally posted by pongmstr2 View Post
                          is this the same as MPPT?
                          No it is not
                          NABCEP certified Technical Sales Professional

                          [URL="http://www.solarpaneltalk.com/showthread.php?5334-Solar-Off-Grid-Battery-Design"]http://www.solarpaneltalk.com/showth...Battery-Design[/URL]

                          [URL]http://www.calculator.net/voltage-drop-calculator.html[/URL] (Voltage drop Calculator among others)

                          [URL="http://www.gaisma.com"]www.gaisma.com[/URL]

                          Comment


                          • #14
                            Originally posted by Naptown View Post
                            No it is not....
                            ...although the effect is similar, in that it takes power at one voltage and current combination and makes it available at a different voltage and current combination. It does not have to have the same sweep sampling capability that an MPPT tracker does.
                            SunnyBoy 3000 US, 18 BP Solar 175B panels.

                            Comment


                            • #15
                              Originally posted by pongmstr2 View Post
                              is this the same as MPPT?
                              Same price though...Ouch

                              For my small applications I'll just run direct.

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