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Some advice on Wiring Panels together

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  • Some advice on Wiring Panels together

    Hi there

    Im just about to attach my new solar panels to the mppt controller 80A outback

    But need some advice on combining the panels

    Ive 16 Schott panels 2 different types 8 of each mono 195w and photo 160w (pictures attached)

    195w panel.jpg

    160w panel.jpg
    This is my thoughts

    Parallel wiring joining 2 panels with mc4 Y connectors to get 8 sets of 2 panels

    Then I assume these 8 sets wires into combiner box? if so I can only seem to get 2, 4 or 6 string combiner boxes so thinking 2 x 4-string boxes, then these into a 2-string, if that makes sense

    secondary questions are the connectors on the smaller panels are not mc4....ok to snip these off and crimp new mc4 connectors on?

    the distance between panels and mppt is 25m.....what size of wire do you think?

    hope someone can advise


    background on my system if it helps - I have 48v rolls 5000 series battery bank hooked up to outback 3kw inverter and outback 80a mppt controller all connected to backup generator

    panels will be facing straight south angel to be determined as yet

    thank you
    Attached Files

  • #2
    This is where a 200 voc. max controller is almost required because your 72 cell panels are considered 24 volt nominal panels. Your 48 volt system would like to see your panels wired 3 in series to get the voltage higher for your MPPT controller to do it's thing. 3 of your panels in series is around 137 volts Voc. In cold conditions that voc. will be higher and really pushing the controllers limits.
    2.2kw Suntech mono, Classic 200, NEW Trace SW4024

    Comment


    • #3
      Ok thats interesting...Im still trying to get my head round this stuff and find some of it difficult

      Ive done some research based on what you say and my controller is max 140 voc min 70 voc

      So what if I do 2 panels in series so 8 sets at say approx 90 voc and then connect these sets up parallel

      I couldn't afford to change the controller

      does that sound like a plausible option?

      Thank you

      Comment


      • #4
        Your voltage will be typical 48 volt nominal with only two panels in series, which will be less than 70 volts at typical rooftop temperatures. At that voltage you might as well use a basic PWM controller. It will work with your controller but you wont really gain much charging power than you would with a PWM controller..
        2.2kw Suntech mono, Classic 200, NEW Trace SW4024

        Comment


        • #5
          ok I think im following

          the panels will be on the ground....on large concrete slab facing south so warm rather than cold most of the time...im in north france also and this is off grid system

          i want to get max out of what i have and think based on what you suggest it might be best with 3 in series even though in cold temps the voc may exceed max controller can take (need to check but assume controller will shut off rather than explode!)

          that would result in 5 sets of 3 with one panel spare

          can i ask if its ok to mix panels as one set would have to be a mix? 1 x160w and 2x195w does this make a difference

          if this is best would I then wire 5 tails into combimer box?

          thank you again for all your assistance

          Comment


          • #6
            Double check what your controller will do with high voltage, most have a memory chip and when voltage is exceeded, they record it and void your warranty. 1 or 3 volts over, it will likely shut down, more than that, expect failure
            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


            • #7
              Mixing panels, here's the rule: (+ or - 10 % still ok)
              Series: Amps should be the same for all, voltage adds
              Parallel, Voltage should be the same, amps add.
              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


              • #8
                genuinely getting confused now lol

                I'm going to go with 8 parallel sets of 2 series

                as i have 2 different types of panels im going to use 2 4-string combiner boxes and then run each into a 2-string combined box

                does this make any sense? what rating should the fuses/breaker be in each box....im thinking 10A in the 160w panel box and 12A in the 190w the 40A and 50A respectivly ???

                sorry with all the questions

                Comment


                • #9
                  The label on the back of the panel will have a spec for the size of protection fuse to use.

                  Midnight has a 8 position solar combiner box, and pick up the right size breakers for your panels.
                  http://www.midnitesolar.com/productP...Order=13&act=p
                  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

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