Issue with solar cell tabbing/wiring into a series...PLEASE HELP!

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  • inetdog
    Super Moderator
    • May 2012
    • 9909

    #16
    Calculation tool and quick sanity check.

    Originally posted by sultan316
    Max current is 3.6 amps and the wire inside the panel I'm assuming will be under 4 ft (almost the length of the panel itself). For outside the panel (where I plan to use the 14 gauge, I'm not sure, but I guess maybe like 20ft? I'm honestly not sure at all though. Haven't really thought about it much since this isn't too serious of a project.
    Using this online voltage drop calculator , which is one of several linked in sticky post in SolarPanelTalk and in some moderators' signatures, I get the voltage drop for a total of 40 ft. of 18ga copper carrying 3.6 amps as 1.2 volts. That is not too bad. If you only use 10 ft. it will be only .6 volts.

    A total of two 4 foot pieces of wire for 8 ft. inside the panel will drop .2 volts.

    Now your 14ga wire could go a 50 foot distance (with two wires) and only drop 1.1 volts. Put your money and effort into large wire where it pays off, and use what fits best and costs less for the rest.
    SunnyBoy 3000 US, 18 BP Solar 175B panels.

    Comment

    • Mike90250
      Moderator
      • May 2009
      • 16020

      #17
      acetone is the only thing that I know of, that will break the silicone seal bond, and not harm the PV cells. The wood will soak it right up, and need a couple days to dry out (acetone will absorb water out of the air, and that will linger in the wood for several days)
      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

      • sultan316
        Member
        • Jun 2012
        • 33

        #18
        Ok cool, then I should be fine with the wiring I have. I don't think I want to try acetone. While it might look a little sketchy, I'm just going to try my luck with the wiring. I'll update you guys with my results when I get the time to do it. Thanks for all the suggestions

        Comment

        • sultan316
          Member
          • Jun 2012
          • 33

          #19
          It works! Thank you guys for your responses and swift help. Even though now it looks very unconventional, it is producing 3x the voltage as a whole versus a single row. I will hopefully try it tomorrow after work in sunlight to see if it reaches the full expected voltage. It's only about 5v indoors with not too much light overhead.

          Next step is to try and glue down the wire to keep it in place. I don't have much room to work with in between the columns unfortunately...

          Comment

          • sultan316
            Member
            • Jun 2012
            • 33

            #20
            Ahh sorry I swear this is the last thing. If I apply silicone to the bus/tabbing wire to attach it to the board, that doesn't create a fire hazard with the current running through it does it? Thanks

            Comment

            • Mike90250
              Moderator
              • May 2009
              • 16020

              #21
              Don't glue it till you are happy with it.

              No, silicone glue/sealer does not "create" a fire hazard. It will burn if you get it hot enough. What
              does happen, is most 1 part silicone in a tube, creates acetic acid (smells like vinegar) as it cures. That
              will mess up delicate electronic parts. The neutral cure/acetone version is hard to find, but electronics safe.
              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

              • Mike90250
                Moderator
                • May 2009
                • 16020

                #22
                Solar cells make nearly full voltage (0.55v per cell) with very little light. To produce full amps, they need full sunlight.
                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

                • axis11
                  Solar Fanatic
                  • Mar 2011
                  • 237

                  #23
                  Dont use ordinary silicon on the bus and tab wires. They will immediately corrode and become black within 24 hours.

                  Comment

                  • jasonp
                    Junior Member
                    • Aug 2012
                    • 1

                    #24
                    I did the same thing.

                    I tryed a 3 string run and had to stop and rethink. Cut all the wire back off and had to use jumper wires. It worked. Now working on a 4 string of 9 cells. I did run into issues at times. All part of learning forthe next project.

                    Comment

                    • OB1CANOGY
                      Junior Member
                      • Aug 2012
                      • 2

                      #25
                      Originally posted by axis11
                      The layout is not exactly the same as it is made of 4 columns of 9's but it should be enough as a guide.


                      EXTREMELY HELPFUL DIAGRAMS!! - thanks.

                      Comment

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