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  • Can someone check my math?

    This is a 24 volt system I am thinking putting together

    Panels:

    LG Mono LG300N1C-B3 305 Watt Panel = ( 5 ) 1525 watts total

    Batteries:

    Rolls Batteries 24 volt S6-460ah = ( 8 )

    4 Batteries in series & 4 Batteries in Parallel. Total AH 960

    960ah X 24volts = 23040 watts / 1000 = 23.05 kwh

    ( using 30% max battery ) 23.05kwh X 30% 7.02 hrs per day of power max!

    Thanks guys

  • #2
    commenting only on the math...

    460 * 2 = 920 (not 960)

    920ah * 24 V = 22.08 kWh * 30% = 6.6 kWh of energy (not "hrs" and "power").

    Edit: I see the rest of the information is in this thread. Are the batteries 460ah or 480ah?
    CS6P-260P/SE3000 - http://tiny.cc/ed5ozx

    Comment


    • #3
      Originally posted by sensij View Post
      commenting only on the math...

      460 * 2 = 920 (not 960)

      22.08 kWh * 30% = 6.6 kWh of energy (not "hrs" and "power").

      Edit: I see the rest of the information is in this thread. Are the batteries 460ah or 480 ah?
      The Rolls Batteries are 460ah AGM's


      Whoops lol Mistype lol Ok so I will get approx. 6.6 kwh per day correct?

      Comment


      • #4
        Originally posted by hozer View Post
        The Rolls Batteries are 460ah AGM's

        Whoops lol Mistype lol Ok so I will get approx. 6.6 kwh per day correct?
        Looks right to me.

        I'm not sure if it was pointed out to you yet, but those panels have STC ratings of 39.8 Voc, with a 9.98 Isc. That charge controller is rated for 150 V max, with a 48 A max Isc at STC. How are you planning on wiring those panels? 5 panels in series is too much voltage, and 5 in parallel would be too much current.
        CS6P-260P/SE3000 - http://tiny.cc/ed5ozx

        Comment


        • #5
          Originally posted by hozer View Post
          The Rolls Batteries are 460ah AGM's


          Whoops lol Mistype lol Ok so I will get approx. 6.6 kwh per day correct?
          Wrong. The batteries are capable of supplying 6.6 Kwh per day, but no way can your panels generate that much in a day.
          MSEE, PE

          Comment


          • #6
            Originally posted by Sunking View Post
            Wrong. The batteries are capable of supplying 6.6 Kwh per day, but no way can your panels generate that much in a day.
            PVWatts for those panels in Grand Junction, CO estimates 6.7 kWh / day annually for south facing, 20 deg tilt. In December and January, the average day is only 4.3 kWh. That assumes the panels are properly matched to a grid-tied inverter. A bad match to a charge controller would, of course, result in less.
            CS6P-260P/SE3000 - http://tiny.cc/ed5ozx

            Comment


            • #7
              Originally posted by sensij View Post
              PVWatts for those panels in Grand Junction, CO estimates 6.7 kWh / day annually for south facing, 20 deg tilt. In December and January, the average day is only 4.3 kWh. That assumes the panels are properly matched to a grid-tied inverter. A bad match to a charge controller would, of course, result in less.
              Thanks guy for all the input. Will check other controllers and let you know which one will work better

              Comment


              • #8
                Originally posted by sensij View Post
                PVWatts for those panels in Grand Junction, CO estimates 6.7 kWh / day annually for south facing, 20 deg tilt. In December and January, the average day is only 4.3 kWh. That assumes the panels are properly matched to a grid-tied inverter. A bad match to a charge controller would, of course, result in less.
                If he keeps his daily use to 20% DOD of the battery capacity (~4.4 kWh) he might be able to put back what he uses.

                Better keep that generator handy to top off the batteries.

                Comment


                • #9
                  Originally posted by sensij View Post
                  PVWatts for those panels in Grand Junction, CO estimates 6.7 kWh / day annually for south facing, 20 deg tilt. In December and January, the average day is only 4.3 kWh. That assumes the panels are properly matched to a grid-tied inverter. A bad match to a charge controller would, of course, result in less.
                  Now go change the efficiency to 66% of a Battery system and see what you get. Battery systems are designed for worse case winter month, not yearly averages. I stand behind my comment.
                  MSEE, PE

                  Comment


                  • #10
                    Originally posted by Sunking View Post
                    Now go change the efficiency to 66% of a Battery system and see what you get. Battery systems are designed for worse case winter month, not yearly averages. I stand behind my comment.
                    I was only adding some data to your comment, not disagreeing. What the panels are capable of supplying is one thing, how much of that is useful energy in the battery system is another. That is why I included the qualifier about grid-tie, and also separated the yearly average from the worst case months. I don't see how our posts conflict.
                    CS6P-260P/SE3000 - http://tiny.cc/ed5ozx

                    Comment


                    • #11
                      Originally posted by sensij View Post
                      I was only adding some data to your comment, not disagreeing. What the panels are capable of supplying is one thing, how much of that is useful energy in the battery system is another. That is why I included the qualifier about grid-tie, and also separated the yearly average from the worst case months. I don't see how our posts conflict.
                      They don't my bad. My apology.
                      MSEE, PE

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