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  • Merging 12 volts panel in 24 volts Panels

    Hi

    want to know what will happen when i will add on 12 volt panel in my 24 volts panel's array ?
    the array is of only 2 large panels of 290 watts each pMax is 36 volts and they are coupled together in parallel to amplify the amps ,8.2 amps each . and then they are connected to EP solar charge controller mppt 40 amps , my question is IF i add only one panel of 12 volts (18 volts pmax) to this grid in parallel OR series what will b the effect on volts / current , will it give me some more amps ? or should i not attach this in parallel but in series to any one panel or both of 24 volt's panel ?

    what the experts recommend ?

  • #2
    Originally posted by nadeem5476 View Post
    Hi

    want to know what will happen when i will add on 12 volt panel in my 24 volts panel's array ?
    the array is of only 2 large panels of 290 watts each pMax is 36 volts and they are coupled together in parallel to amplify the amps ,8.2 amps each . and then they are connected to EP solar charge controller mppt 40 amps , my question is IF i add only one panel of 12 volts (18 volts pmax) to this grid in parallel OR series what will b the effect on volts / current , will it give me some more amps ? or should i not attach this in parallel but in series to any one panel or both of 24 volt's panel ?

    what the experts recommend ?
    You have not said anything about the amps (Imp) of the 12V panel. If the 12V panel.

    Your 290W panels with Vmp = 36V should have an Imp of 8.06. Two of them in parallel should give 16.1A if they operate at full nominal power (which is not likely most of the time for any panel.)
    If your 12V panel has an Imp which is within 5% of 16A, then you could connect it in series with the parallel combination of the other two panels.
    If you try to connect it in parallel with your existing setup, it will not contribute any energy at all, and may suck up energy through reverse current.
    You also cannot put it in series with one panel and then parallel that with the other single panel, even if the two panels Imp values were close.
    The general rule (except when using a PWM controller) is that you can only parallel two panels or strings with matching total voltage and you can only series elements with nearly the same current.
    Your 12V panel is so mismatched with the others that it would best be used to separate MPPT CC input or to a totally separate system.
    SunnyBoy 3000 US, 18 BP Solar 175B panels.

    Comment


    • #3
      Originally posted by inetdog View Post
      You have not said anything about the amps (Imp) of the 12V panel. If the 12V panel.

      Your 290W panels with Vmp = 36V should have an Imp of 8.06. Two of them in parallel should give 16.1A if they operate at full nominal power (which is not likely most of the time for any panel.)
      If your 12V panel has an Imp which is within 5% of 16A, then you could connect it in series with the parallel combination of the other two panels.
      If you try to connect it in parallel with your existing setup, it will not contribute any energy at all, and may suck up energy through reverse current.
      You also cannot put it in series with one panel and then parallel that with the other single panel, even if the two panels Imp values were close.
      The general rule (except when using a PWM controller) is that you can only parallel two panels or strings with matching total voltage and you can only series elements with nearly the same current.
      Your 12V panel is so mismatched with the others that it would best be used to separate MPPT CC input or to a totally separate system.
      thanks for the reply , please clear one thing what you mean by within 5 percent of 16A ? the Imp of that 12 volt panel is 8.4 Amps so can i connect that in series with the 24 volts array ?

      regarding the separate mppt : i cant use separate charge controller as the battery bank is of 24 volts and this 12 volts panel wont charge the battery bank .

      new question is that can we use 2 different brands mppt or pwm charge controllers on same battery bank ?

      thanks for the time

      Comment


      • #4
        Originally posted by nadeem5476 View Post
        thanks for the reply , please clear one thing what you mean by within 5 percent of 16A ? the Imp of that 12 volt panel is 8.4 Amps so can i connect that in series with the 24 volts array ?

        regarding the separate mppt : i cant use separate charge controller as the battery bank is of 24 volts and this 12 volts panel wont charge the battery bank .

        new question is that can we use 2 different brands mppt or pwm charge controllers on same battery bank ?

        thanks for the time
        The 12v panel would have to be within 5% of the total imp of the 24v panels (16.1v)

        With a 24 volt battery bank there is no way you can use only 1 12v panel. You would need to add 2 of them.

        WWW

        Comment


        • #5
          Simple answer, it won't work, it will draw down the other panels. I never heard of any battery panel with 288 watts ( I could be wrong).

          Comment


          • #6
            Originally posted by paulcheung View Post
            Simple answer, it won't work, it will draw down the other panels. I never heard of any battery panel with 288 watts ( I could be wrong).
            You are correct. 12 volt battery panels only go up to around 160 watts.
            MSEE, PE

            Comment


            • #7
              Originally posted by Wy_White_Wolf View Post
              The 12v panel would have to be within 5% of the total imp of the 24v panels (16.1v)

              With a 24 volt battery bank there is no way you can use only 1 12v panel. You would need to add 2 of them.

              WWW
              i still couldnt understand that WITHIN thing . please let me know what would b the Imp within 5% of 16.1 A ?

              Comment


              • #8
                so can i attach all of them in series ? (using mppt charge controller 40 amps Ep solar)

                1st panel : 36 volts pmax and 8.1 Amps Imp , Voc 44 volts
                2nd panel: 36 volts pmax and 8.1 Amps Imp , Voc 44 volts
                3rd Panel: 18 volts Pmax and 8.45 Imp , Voc , 22 volts

                ??

                Comment


                • #9
                  Originally posted by nadeem5476 View Post
                  i still couldnt understand that WITHIN thing . please let me know what would b the Imp within 5% of 16.1 A ?
                  Within 5% would be between 15.3A (16.1-5%) and 16.9A (16.1+5%). The panel is nowhere close to that.

                  WWW

                  Comment


                  • #10
                    Originally posted by nadeem5476 View Post
                    so can i attach all of them in series ? (using mppt charge controller 40 amps Ep solar)

                    1st panel : 36 volts pmax and 8.1 Amps Imp , Voc 44 volts
                    2nd panel: 36 volts pmax and 8.1 Amps Imp , Voc 44 volts
                    3rd Panel: 18 volts Pmax and 8.45 Imp , Voc , 22 volts

                    ??
                    You could if you had a 60 amp MPPT controller with a VOC input of more than 150 volts. With a 40 amp MPPT controller you are limited to 500 watts @ 12 volt battery. All three in series wattage = 720 watts. If your battery is 24 volts you can if your controller input is 150 VOC
                    MSEE, PE

                    Comment


                    • #11
                      If this is your charge controller there is no configuration that you can use all 3 panels. It has a 100v input limit.

                      WWW

                      Comment

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