48v battery bank help

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  • Dmonicle
    Junior Member
    • Oct 2015
    • 20

    #1

    48v battery bank help

    MY PV array is reading around 86 volts and I'm using a Classic 150 CC. I'd like to run a 48v battery. My question is ...

    If I have (4) 100ah 12v batteries wired in series to make a 100ah 48v battery, would I get as much energy as I would from a 400ah 12v battery? (Meaning the same 4 batteries wired in parallel to make a 400ah 12v bank.)

    thanks in advance!
    Last edited by Dmonicle; 02-20-2016, 04:44 PM.
  • organic farmer
    Solar Fanatic
    • Dec 2013
    • 663

    #2
    Four 12vdc batteries each with 100ah, gives you 48dc with 100ah [4800watts]

    A single 12vdc battery with 400ah, gives you 12vdc with 400ah [4800watts]
    4400w, Midnite Classic 150 charge-controller.

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    • Dmonicle
      Junior Member
      • Oct 2015
      • 20

      #3
      Thanks for the reply, what I'm trying to figure out is if a 48v inverter has equal amount of energy available with the 4 batteries in series as a 12v inverter has with the same 4 batteries in parallel.
      Last edited by Dmonicle; 02-20-2016, 04:50 PM.

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      • inetdog
        Super Moderator
        • May 2012
        • 9909

        #4
        Originally posted by Dmonicle
        Thanks for the reply, what I'm trying to figure out is if a 48v inverter has the same amount of energy available with the 4 batteries in series as a 12v inverter has with them in parallel.
        Yes, but the wiring to the 12V inverter will have to carry four times the current and so will have to use inconveniently large wires.
        And the four batteries in series will be a maintenance problem.
        SunnyBoy 3000 US, 18 BP Solar 175B panels.

        Comment

        • organic farmer
          Solar Fanatic
          • Dec 2013
          • 663

          #5
          Originally posted by Dmonicle
          Thanks for the reply, what I'm trying to figure out is if a 48v inverter has equal amount of energy available with the 4 batteries in series as a 12v inverter has with the same 4 batteries in parallel.
          48v inverters have 120/240vac outputs.
          4400w, Midnite Classic 150 charge-controller.

          Comment

          • Logan005
            Solar Fanatic
            • Nov 2015
            • 490

            #6
            Don't waste your time with 12 volt battery bank, never parallel batteries. a 12 volt inverter is a toy.
            4X Suniva 250 watt, 8X t-105, OB Fx80, dc4812vrf

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            • Sunking
              Solar Fanatic
              • Feb 2010
              • 23301

              #7
              Originally posted by organic farmer
              Four 12vdc batteries each with 100ah, gives you 48dc with 100ah [4800watts]

              A single 12vdc battery with 400ah, gives you 12vdc with 400ah [4800watts]
              Wrong answer.

              4 x 12 volts x 100 AH = 4800 WATT HOURS

              MSEE, PE

              Comment

              • Sunking
                Solar Fanatic
                • Feb 2010
                • 23301

                #8
                Originally posted by Dmonicle
                Thanks for the reply, what I'm trying to figure out is if a 48v inverter has equal amount of energy available with the 4 batteries in series as a 12v inverter has with the same 4 batteries in parallel.
                Your question has been answered 4800 wh = 4800 wh, but one very important fact has been left out. It takes 4 times the current at 12 volts as opposed to 48 volts of a given power level. 48 volts is much safer, less expensive, and more efficient.

                Children and the clueless play with 12 volt toys, systems are 24 and 48 volts.

                A 12 volt system is pretty much limited to 1000 watts of panels, 800 AH batteries, and 1000 watt Inverter. To go any larger requires a second 12 volt system.

                24 volt systems are limited to 2000 watts, 800 AH battery, and 2000 watt Inverter. To go any higher requires a second system.

                48 volts is limited to about 4000 watts, 800 AH battery, and 4000 watt inverter.
                MSEE, PE

                Comment

                • Dmonicle
                  Junior Member
                  • Oct 2015
                  • 20

                  #9
                  Originally posted by Sunking
                  Your question has been answered 4800 wh = 4800 wh, but one very important fact has been left out. It takes 4 times the current at 12 volts as opposed to 48 volts of a given power level. 48 volts is much safer, less expensive, and more efficient.
                  Thanks Sunking,

                  so an identical load on a 100ah 48v battery will have the same energy reserve as it would on a 400ah 12v battery?

                  Comment

                  • Sunking
                    Solar Fanatic
                    • Feb 2010
                    • 23301

                    #10
                    Originally posted by Dmonicle
                    Thanks Sunking, so an identical load on a 100ah 48v battery will have the same energy reserve as it would on a 400ah 12v battery?
                    You tell me as we have answered that many times, With 4 12 volt 100 AH batteries you have 3 possible configurations:

                    12 volts x 400 AH = 4800 Watt Hours
                    24 volts x 200 AH = 4800 Watt Hours
                    48 volts x 100 AH = 4800 Watt Hours

                    Which one is better? a 12 volt 100 AH battery has a capacity of 12 volt x 100 AH = 1200 Watt Hours. POWER and ENERGY ADDS always regardless of how it is configured being parallel or series.

                    On paper and in thoery they are all equal, in practice 48 volts is superior because it cost less to implement, more efficient, and safer. NEVER EVER parallel batteries unless absolutely necessary. If you need 400 AH buy 400 AH batteries. Your problem is you are stuck inside a 12 volt box. You have it in your head batteries are 12 volts which is dead wrong and void of facts. Lead acid batteries are 2-volts and come in sizes of 1 AH to 6000 AH. There is no such thing as a 12 volt 6000 AH battery. It would weigh 4000 pounds. But you can buy a 2 volt 6000 AH battery like the USN and some telephone companies use. Those weigh in around 670 pounds each.

                    About the largest 12 volt battery you can buy is 200 AH and a back breaking finger crushing 200 pounds. Lead Acid batteries come in 2, 4, 6, 8, 12, 24, and 36 volts for railroad.
                    Last edited by Sunking; 02-20-2016, 06:27 PM.
                    MSEE, PE

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                    • Dmonicle
                      Junior Member
                      • Oct 2015
                      • 20

                      #11
                      Awesome, 48v it is then!

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