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120W - 160W solar panel charging potential on 48V system?

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  • 120W - 160W solar panel charging potential on 48V system?

    Hi people, new to this forum and to understanding the specifics of how solar charging works so appreciate any input here.
    My question is, how much impact would a single 120W or 160W solar panel have on a 48V battery bank (6 x 8V deep cycle batteries)? Using a 48V controller. Im just interested in assisting the charging of the batteries throughout the day. The system is charged daily by AC every night. Any idea on what percentage of charge I might gain from those panels?
    Thanks
    Tony

  • #2
    If you are running enough power, that you need a 48V battery bank, a single 200w panel won't do much.

    Not many low wattage panels produce 60V which is needed to recharge a 48v bank.

    200w might be the same amount as daily self-discharge.

    Hope this helps. (knowing the Ah of the battery bank would help define the answer)
    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


    • #3
      Originally posted by Mike90250 View Post
      If you are running enough power, that you need a 48V battery bank, a single 200w panel won't do much.

      Not many low wattage panels produce 60V which is needed to recharge a 48v bank.

      200w might be the same amount as daily self-discharge.

      Hope this helps. (knowing the Ah of the battery bank would help define the answer)

      Thanks for your input Mike.
      The 120W panel produces 60V and the 160W panel up to 70V.
      The attached pic has the individual battery details and there is a pic of the solar panel info as well.
      Does that help to narrow it down?
      Attached Files

      Comment


      • #4
        The voltage is enough, but the power is still a drop in the bucket.
        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


        • #5
          Originally posted by Tony09 View Post
          Hi people, new to this forum and to understanding the specifics of how solar charging works so appreciate any input here.
          My question is, how much impact would a single 120W or 160W solar panel have on a 48V battery bank (6 x 8V deep cycle batteries)? Using a 48V controller. Im just interested in assisting the charging of the batteries throughout the day. The system is charged daily by AC every night. Any idea on what percentage of charge I might gain from those panels?
          A FLA battery requires a minimum of C/12 charge current an no more than C/8 with C/10 being perfect. A 200 watt panel operating on 48 volts only generates 200 watts / 48 volts = 4.2 amps. That means the largest battery it could possible support is 8 x 4.2 amps = 34 AH. I bet those 8 volt batteries are up around 150 to 180 AH? If that is the case you would need a minimum 700 watts up to 1200 watts of panels. You are not even remotely close to that. And if you have a PWM controller you would need considerable more panel wattage. A 200 watt system is 12 volt battery toy territory. 480 volts system typically start at 800 to 1000 panel watts.

          But to answer your question the 120 watt panel is not really doing much of anything at all. I also suspect you are using a PWM controller and if that is true instead of 2.5 amps you are only getting 1.7 amps from the panel. Kind of like peeing in the ocean hoping to raise the sea level.
          MSEE, PE

          Comment


          • #6
            Originally posted by Mike90250 View Post
            The voltage is enough, but the power is still a drop in the bucket.
            Thanks again Mike

            Comment


            • #7
              Originally posted by Sunking View Post
              A FLA battery requires a minimum of C/12 charge current an no more than C/8 with C/10 being perfect. A 200 watt panel operating on 48 volts only generates 200 watts / 48 volts = 4.2 amps. That means the largest battery it could possible support is 8 x 4.2 amps = 34 AH. I bet those 8 volt batteries are up around 150 to 180 AH? If that is the case you would need a minimum 700 watts up to 1200 watts of panels. You are not even remotely close to that. And if you have a PWM controller you would need considerable more panel wattage. A 200 watt system is 12 volt battery toy territory. 480 volts system typically start at 800 to 1000 panel watts.

              But to answer your question the 120 watt panel is not really doing much of anything at all. I also suspect you are using a PWM controller and if that is true instead of 2.5 amps you are only getting 1.7 amps from the panel. Kind of like peeing in the ocean hoping to raise the sea level.

              Appreciate the feedback Sunking and for the detailed explanation. I was hoping these panels would at least assist (even 10% would have been ok) but from what you are saying there, it seems it is not even close to having much effect.
              There is limited space to fit the solar panel so unfortunately there is not an option of increasing the amount of panels.
              Thanks again for your input.

              Comment


              • #8
                Pretty interesting. I am going to follow up see if others haven input.

                Comment


                • #9
                  Originally posted by Sunking View Post
                  A FLA battery requires a minimum of C/12 charge current an no more than C/8 with C/10 being perfect. A 200 watt panel operating on 48 volts only generates 200 watts / 48 volts = 4.2 amps. That means the largest battery it could possible support is 8 x 4.2 amps = 34 AH. I bet those 8 volt batteries are up around 150 to 180 AH? If that is the case you would need a minimum 700 watts up to 1200 watts of panels. You are not even remotely close to that. And if you have a PWM controller you would need considerable more panel wattage. A 200 watt system is 12 volt battery toy territory. 480 volts system typically start at 800 to 1000 panel watts.

                  But to answer your question the 120 watt panel is not really doing much of anything at all. I also suspect you are using a PWM controller and if that is true instead of 2.5 amps you are only getting 1.7 amps from the panel. Kind of like peeing in the ocean hoping to raise the sea level.

                  Just a follow up on this one again Sunking, the controller is an MPPT 30.
                  Just want to clarify something here. With my intention being only to assist the charging of these batteries and with only enough space for one solar panel, what would be the minimum wattage panel I would need to have even a small impact? Even something like 10% charging would be acceptable at this stage.

                  The peeing in the ocean analogy probably answers that already but just wanted to be sure before I give up on the idea.

                  Comment

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