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  • 12volts or 24 volts setup?

    Hello again everyone!

    Here's my dilemna now, I have these things just bought:

    4x 100watt solar panels 17volts @5.71Amp each
    4 x 12volts 100Ah (RC/20) AGM Deep Cycle Batteries
    Wellsee 40A solar controller (http://www.wellsee.cc/ProContent_Editor.aspx?action=94)
    1kva pure sine wave inverter

    I'm currently contemplating on whether I go for a 12v @ 400AH system setup or a 24v 200AH setup? In my previous post, I was asking whether my panels are enough to charge my batteries.

    Appreciate the help! Thanks!
    -Ameds-
    [URL="My starter solar setup"]http://www.facebook.com/album.php?aid=110199&id=1460868554&l=8dbb187d24[/URL]
    [URL="Video of my solar setup"]http://www.youtube.com/watch?v=xEq-6Lc3_SI[/URL]

  • #2
    Your load demands factor heavily in the voltage decision. If you never have over 1,000w of load (including motor starting surge) then 12V would work. If you go above 1,000W -2,000w, then a 24V system is better, less amps at the batteries needed. Above 2,000w, consider a 48V system
    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


    • #3
      Originally posted by Mike90250 View Post
      Your load demands factor heavily in the voltage decision. If you never have over 1,000w of load (including motor starting surge) then 12V would work. If you go above 1,000W -2,000w, then a 24V system is better, less amps at the batteries needed. Above 2,000w, consider a 48V system
      Thanks Mike!

      I will seriously consider your advice, my only concern is that: Won't a 24v system would make me worry less with the cable sizes and lenght? That's my only reason why I'm considering a 24v setup. Any thoughts on that?

      Thanks!
      -Ameds-
      [URL="My starter solar setup"]http://www.facebook.com/album.php?aid=110199&id=1460868554&l=8dbb187d24[/URL]
      [URL="Video of my solar setup"]http://www.youtube.com/watch?v=xEq-6Lc3_SI[/URL]

      Comment


      • #4
        Yes, a 24V system has more leeway with voltage loss, and cable length issues, but I would still practice some sanity with using proper sizes and lengths.
        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
          Yes, a 24V system has more leeway with voltage loss, and cable length issues, but I would still practice some sanity with using proper sizes and lengths.
          With my current setup Mike, what wire size can you recommend if ever I go to the 12v route? No wire will ever go longer than 10 feet.

          Thanks!
          -Ameds-
          [URL="My starter solar setup"]http://www.facebook.com/album.php?aid=110199&id=1460868554&l=8dbb187d24[/URL]
          [URL="Video of my solar setup"]http://www.youtube.com/watch?v=xEq-6Lc3_SI[/URL]

          Comment


          • #6
            I've still got no idea what your loads (on the AC side of the inverter) are.
            120V or 240V inverter?
            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
              The minimum size wire will be listed with the inverter instructions.
              MSEE, PE

              Comment


              • #8
                Originally posted by Mike90250 View Post
                I've still got no idea what your loads (on the AC side of the inverter) are.
                120V or 240V inverter?
                240v mike! Total computed loads would be 500 - 600 watts for 4 hourds per day.
                -Ameds-
                [URL="My starter solar setup"]http://www.facebook.com/album.php?aid=110199&id=1460868554&l=8dbb187d24[/URL]
                [URL="Video of my solar setup"]http://www.youtube.com/watch?v=xEq-6Lc3_SI[/URL]

                Comment


                • #9
                  Originally posted by Sunking View Post
                  The minimum size wire will be listed with the inverter instructions.
                  Unfortunately, the inverter did not specify the required wire sizes. That's why I was hoping on finding answers in this forum.

                  Thanks!
                  -Ameds-
                  [URL="My starter solar setup"]http://www.facebook.com/album.php?aid=110199&id=1460868554&l=8dbb187d24[/URL]
                  [URL="Video of my solar setup"]http://www.youtube.com/watch?v=xEq-6Lc3_SI[/URL]

                  Comment


                  • #10
                    Originally posted by raymondalmeda View Post
                    Unfortunately, the inverter did not specify the required wire sizes. That's why I was hoping on finding answers in this forum.
                    What is the VA rating of the Inverter? 100 watts, 2000 watts, what?

                    IF your inverter does not specify the minimum size wire and breaker needed on the battery input, you need to find another manufacture.
                    MSEE, PE

                    Comment


                    • #11
                      Originally posted by Sunking View Post
                      What is the VA rating of the Inverter? 100 watts, 2000 watts, what?

                      IF your inverter does not specify the minimum size wire and breaker needed on the battery input, you need to find another manufacture.
                      The Inverter is rated @ 1KVA, power factor of 87% so maximum continuous rating is 870watts, surge rating is 1600watts.

                      Thanks!
                      -Ameds-
                      [URL="My starter solar setup"]http://www.facebook.com/album.php?aid=110199&id=1460868554&l=8dbb187d24[/URL]
                      [URL="Video of my solar setup"]http://www.youtube.com/watch?v=xEq-6Lc3_SI[/URL]

                      Comment


                      • #12
                        Voltage Drop Calculator :

                        http://www.nooutage.com/vdrop.htm
                        http://www.electrician2.com/vd_calculator.htm
                        http://www.elec-toolbox.com/calculators/voltdrop.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


                        • #13
                          At 12 volt input you will need a 125 amp fuse and a minimum 1 AWG copper conductor.
                          At 24 volt you need a 60 amp fuse, and a minimum #6 AWG copper conductor.
                          MSEE, PE

                          Comment


                          • #14
                            Originally posted by Mike90250 View Post
                            Your load demands factor heavily in the voltage decision. If you never have over 1,000w of load (including motor starting surge) then 12V would work. If you go above 1,000W -2,000w, then a 24V system is better, less amps at the batteries needed. Above 2,000w, consider a 48V system
                            You looks like a specialist on this
                            Last edited by russ; 12-24-2010, 02:19 AM. Reason: link removed

                            Comment


                            • #15
                              i am not good at this calculation but i learn that in school, P have bigger lost in 12 wires than same P in 240 wires and much smaller in 240 (50-60Hz)

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