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  • #31
    Originally posted by Sunking View Post
    You cannot use the 200 watt panels on a 12 volt battery with a PWM controller. I do not need to see the specs because there is no such thing as a 200 watt 12 volt battery panel.If you did two things happen and neither is good.
    How about this "Solar-Panel-12V-200W-Monocrystalline-Module-House-Caravan-Boat-Off-Grid-Use" from this ebay ad http://www.ebay.com.au/itm/Solar-Pan...8AAOSwyjBW8J7s, and by the way this is not the only one.

    Simon

    Off grid 24V system, 6x190W Solar Panels, 32x90ah Winston LiFeYPO4 batteries installed April 2013
    BMS - Homemade Battery logger github.com/simat/BatteryMonitor
    Latronics 4kW Inverter, homemade MPPT controller
    Off-Grid LFP(LiFePO4) system since April 2013

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    • #32
      Originally posted by Sunking View Post
      OK if you parallel the three panels, the input current into the PWM controller is 3 x 7.53 amps = 22.59 amps. That means the output current is 22.59 amps into a 12 volt battery = 271 watts from 660 watts of panel power. The issue is the PWM controller. Now if that were 24 volt batteries everything is fine and dandy. Still the same 22.6 amps but at 24 volts is 540 watts from 660 watts of panels.
      I made a mistake with the 27A, your figure of 22.59A is also incorrect. The current output from a solar panel increases from Imp at an output voltage of Vmp to a maximum current of Isc at an output voltage of 0 volts. This increase in current is around 12%.

      The increase in current is fairly linear with voltage so for an output of around 13V the increase in this case is around 5% so FWIW the input current into the PWM will be ~24A.

      Simon

      Off grid 24V system, 6x190W Solar Panels, 32x90ah Winston LiFeYPO4 batteries installed April 2013
      BMS - Homemade Battery logger github.com/simat/BatteryMonitor
      Latronics 4kW Inverter, homemade MPPT controller
      Off-Grid LFP(LiFePO4) system since April 2013

      Comment


      • #33
        Originally posted by karrak View Post

        I made a mistake with the 27A, your figure of 22.59A is also incorrect. The current output from a solar panel increases from Imp at an output voltage of Vmp to a maximum current of Isc at an output voltage of 0 volts. This increase in current is around 12%.

        The increase in current is fairly linear with voltage so for an output of around 13V the increase in this case is around 5% so FWIW the input current into the PWM will be ~24A.

        Simon

        Off grid 24V system, 6x190W Solar Panels, 32x90ah Winston LiFeYPO4 batteries installed April 2013
        BMS - Homemade Battery logger github.com/simat/BatteryMonitor
        Latronics 4kW Inverter, homemade MPPT controller
        What you posted is really just theoretical. Even that Imp = 7.53amps is not a real number. It is a value that was generated in the LAB under very strict conditions.

        More than likely that panel will never put out much above 7 amps let alone seeing a 12% increase as the voltage goes down to 0.

        If you plan on providing information try to keep it real and be a little more up front with any warning about doing something that could result in a fire or worse. Try to remember the majority of the forum members and visitors have very little hands on experience with electrical circuitry let along understand solar and battery technology.

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        • #34
          Karrak you are a hack. Get lost, you are not welcome here.
          MSEE, PE

          Comment


          • #35
            Originally posted by Sunking View Post

            Second time, maybe he will take the hint and not come back.By his own admission only came here to harrass me.
            No Sunking, I initially came to this forum to put a counter argument to yours regarding balancing LFP batteries. I would say the harassment has been the other way around. I was first harassed by Russ who was a moderator at that time and then repeatedly by you, usually whenever you are trying to defend the indefensible.

            Simon

            Off grid 24V system, 6x190W Solar Panels, 32x90ah Winston LiFeYPO4 batteries installed April 2013
            BMS - Homemade Battery logger github.com/simat/BatteryMonitor
            Latronics 4kW Inverter, homemade MPPT controller
            Off-Grid LFP(LiFePO4) system since April 2013

            Comment


            • #36
              Originally posted by karrak View Post

              No Sunking, I initially came to this forum to put a counter argument to yours regarding balancing LFP batteries. I would say the harassment has been the other way around. I was first harassed by Russ who was a moderator at that time and then repeatedly by you, usually whenever you are trying to defend the indefensible.

              Simon

              Off grid 24V system, 6x190W Solar Panels, 32x90ah Winston LiFeYPO4 batteries installed April 2013
              BMS - Homemade Battery logger github.com/simat/BatteryMonitor
              Latronics 4kW Inverter, homemade MPPT controller
              And, if memory serves, also apparently given a couple of R & R's by mods for what was considered either incorrect or dangerous information, or both.

              Comment


              • #37
                Originally posted by karrak View Post
                No Sunking, I initially came to this forum to put a counter argument to yours regarding balancing LFP batteries. I would say the harassment has been the other way around.
                Simon you are a proven liar. You came here for one reason and one reason only. All the Mods know it and are itching to ban you permanently. You got what you asked for. Now get lost, you have no credibility here and are a danger to the public. If Russ were still here, you would have been gone long long ago.
                MSEE, PE

                Comment


                • #38
                  Originally posted by J.P.M. View Post

                  And, if memory serves, also apparently given a couple of R & R's by mods for what was considered either incorrect or dangerous information, or both.
                  It was actually once before and it was the same moderator.
                  Off-Grid LFP(LiFePO4) system since April 2013

                  Comment


                  • #39
                    Originally posted by karrak View Post

                    It was actually once before and it was the same moderator.
                    That's because the other Moderator beat me to the punch.

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