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Need help figuring out PV Panel with high amp cells.

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  • Need help figuring out PV Panel with high amp cells.

    Ok so I found cells the put out 4.35 Watts .5 Volts and 8.7 Amps a cell.

    Im starting to think that the listing is incorrect

    I would like to do a 24v system and thats fine at first 48 Cells at .5 volts=24Volts. Well this is where I get lost.

    48 cells parallel x .5volts=24v Great
    48 cells parallel x 4.35watts=208.8 Watts Great
    48 cells parallel x 8.7 Amps= 417.8 Amps Not great

    If you look at 417.8Amps x 24volts=10027 Watts
    and 208.8 watts / .5 volts = 417.8 amps
    I'm not sure if the listing is correct but I don't think they make a Solar Regulator to handle 417.8 Amps
    I would like to run 30A Solar Regulators

    Am I loosing my mind or did I forget something.

    or Does Amps stay the same under a parallel connection?

  • #2
    Originally posted by eclivic View Post
    Ok so I found cells the put out 4.35 Watts .5 Volts and 8.7 Amps a cell.

    Im starting to think that the listing is incorrect

    I would like to do a 24v system and thats fine at first 48 Cells at .5 volts=24Volts. Well this is where I get lost.

    48 cells parallel x .5volts=24v Great
    48 cells parallel x 4.35watts=208.8 Watts Great
    48 cells parallel x 8.7 Amps= 417.8 Amps Not great

    If you look at 417.8Amps x 24volts=10027 Watts
    and 208.8 watts / .5 volts = 417.8 amps
    I'm not sure if the listing is correct but I don't think they make a Solar Regulator to handle 417.8 Amps
    I would like to run 30A Solar Regulators

    Am I loosing my mind or did I forget something.

    or Does Amps stay the same under a parallel connection?
    You are confused on how to add up the volts and amps for those cells.

    First off 48 cells in "series" adds up to 24 volts. The 8.7 amps for those 48 "series" stays the same. You do not add them up to get 417.8 amps.

    So for 48 cells in "series" you get 24 volts times 8.7 amps = 208.8 watts.

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    • #3
      It takes 72 cells in series for a 24 volt battery panel.
      MSEE, PE

      Comment


      • #4
        Sunking is correct about the number of cells needed for a 24 volt battery system.

        I got caught up with trying to explain about series and parallel and forgot to tell you that the panel voltage needs to be high enough to charge your 24 volt battery. That is more than 30 volts which requires more than 60 cells at 0.5 volts per cell.

        Comment


        • #5
          Originally posted by Sunking View Post
          It takes 72 cells in series for a 24 volt battery panel.
          Wouldnt that be 35 volts at .5 x 75 cells?

          Comment


          • #6
            Originally posted by eclivic View Post
            Wouldnt that be 35 volts at .5 x 75 cells?
            Yes sir and that is what it takes to charge a 24 volt battery.
            MSEE, PE

            Comment


            • #7
              Originally posted by Sunking View Post
              Yes sir and that is what it takes to charge a 24 volt battery.
              Is that because of the 30% you should add extra for drops and shade

              Comment


              • #8
                Originally posted by eclivic View Post
                Is that because of the 30% you should add extra for drops and shade
                No, that is the VOLTAGE required to charge a 24V battery. PV panels produce their rated voltage at very low light levels, and then the brighter the light, the more amps they produce. The expected 30% loss is on the amps, from less than optimum aim, dust, haze in the sky.......
                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


                • #9
                  Originally posted by eclivic View Post
                  Wouldnt that be 35 volts at .5 x 75 cells?
                  No, it would be 37.5 volts.
                  The most common panels for charging a 24 volt battery bank are 72 cells for a total of 36 volts.
                  72 is used because it divides up into a rectangular pattern (such as 9x8 or 6x12) much better than 75 would. A pattern of 3x25 or 5x15 makes for a harder to handle panel.
                  SunnyBoy 3000 US, 18 BP Solar 175B panels.

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