Automatic switching from parallel to series panel connection

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • Argent
    Junior Member
    • May 2015
    • 4

    #1

    Automatic switching from parallel to series panel connection

    I have two 12v panels (1 amp max each) hooked up to four 12v deep cycle batteries.

    The weather in the UK provides for a fairly brief recharging time.

    I was thinking that if I connected the panels in series that might boost the voltage, when it drops during cloudy weather, sufficient to enable charging to continue.
    First question: does this sound plausible?

    I was hoping I might be able to find a voltage-sensing switch that would enable me to swop automatically from parallel to series connection when the panels' output voltage dropped below - say - 13v, but haven't found anything.
    Any ideas?

    I think I've figured out a way to enable switching from parallel to series connection using a relay wired across one panel, which I was thinking might have a 'release' voltage of around 13v (i.e. at 13v or below the contacts would revert to their normal position, and so connecting the panels in series): this would presumably require some experimentation with relays to find one that triggers at over 13v (or via a variable resistor). This option seems a bit messy, so I am hoping there is some sort of voltage-sensing switch out there!

    Any ideas, suggestions or pity, welcome.
    Thanks.
  • sensij
    Solar Fanatic
    • Sep 2014
    • 5074

    #2
    Panel voltage doesn't drop when it is cloudy, the panel current does. The switching scheme you are suggesting will not do you any good.
    CS6P-260P/SE3000 - http://tiny.cc/ed5ozx

    Comment

    • Amy@altE
      Solar Fanatic
      • Nov 2014
      • 1023

      #3
      Your best bet is to get an MPPT charge controller, wire the panels in series, and let the charge controller do its thing.
      Solar Queen
      altE Store

      Comment

      • Sunking
        Solar Fanatic
        • Feb 2010
        • 23301

        #4
        Originally posted by Argent
        I was thinking that if I connected the panels in series that might boost the voltage, when it drops during cloudy weather, sufficient to enable charging to continue.
        First question: does this sound plausible?
        No, panel voltage does not drop when cloudy, current falls to nothing leaving you no power. Get a MPPT charger wire the panels in series and quit worrying about it. When clouds come over you still have no power to speak of. That is how it works.
        MSEE, PE

        Comment

        • Bala
          Solar Fanatic
          • Dec 2010
          • 734

          #5
          Originally posted by Argent
          I have two 12v panels (1 amp max each) hooked up to four 12v deep cycle batteries.


          Any ideas, suggestions or pity, welcome.
          Thanks.
          If, as you say, the two panels are only one amp each connected to four batteries you may need to get some more panels.

          Comment

          • Sunking
            Solar Fanatic
            • Feb 2010
            • 23301

            #6
            Originally posted by Bala
            If, as you say, the two panels are only one amp each connected to four batteries you may need to get some more panels.
            Did no tcatch that part. What is he charging? A cell phone battery as that is about all it would charge.
            MSEE, PE

            Comment

            • Bala
              Solar Fanatic
              • Dec 2010
              • 734

              #7
              Originally posted by Sunking
              Did no tcatch that part. What is he charging? A cell phone battery as that is about all it would charge.
              will need to wait for the OP, original post says

              I have two 12v panels (1 amp max each) hooked up to four 12v deep cycle batteries

              Comment

              • Sunking
                Solar Fanatic
                • Feb 2010
                • 23301

                #8
                Originally posted by Bala
                will need to wait for the OP, original post says
                You can wait, I am not going to wait for such silliness.
                MSEE, PE

                Comment

                • Bala
                  Solar Fanatic
                  • Dec 2010
                  • 734

                  #9
                  Originally posted by Sunking
                  You can wait, I am not going to wait for such silliness.
                  You will be back to see, you wont be able to help youself

                  Comment

                  • Argent
                    Junior Member
                    • May 2015
                    • 4

                    #10
                    Thank you for the responses.

                    I was basing my assessment on a voltmeter output which appeared to show a reducing output voltage when the sunlight diminished. I was under the impression that the voltage output of some types of panel does fall off rapidly in poor light, but that other panels show a more gradually-reducing output curve. Thanks for the enlightenment.

                    Thank you for the advice on the MPPT charge controller and wiring in series: I shall look into that.

                    I do have another panel and am going to add that in (for what difference that will make). Higher-output panels would be great, and I have been looking into that aspect, but it isn't a life-priority right now. The set-up was for fun, and the result of various opportunities rather than design. The batteries were a bargain. The solar panels were on offer. The load on the system has been minimal and the trickle charging has sufficed for some time now: a recently increased load is showing up the inadequacy of the system, hence this enquiry.

                    Comment

                    Working...