Problems with charge controller

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  • metobi1
    Junior Member
    • Apr 2015
    • 10

    Problems with charge controller

    Hi all, I am totally new to solar tech and so I really need your help in solving an issue. I am using a 5KVA inverter, with 4 batteries. This was connected as a 48v battery system, for which I have tried installing a solar charging system. To do this I bought:
    - 6 200W 24V 5.4A solar panels.
    - A 48V, 60A mppt charge controller, with a working voltage of 70V.

    I initially connected the solar panels on my roof as follows -

    I divided the 6 solar panels into 3 sets of 2 and I connected each set in series, to get 48V (2 in series), and then I connected the 3 sets in parallel to get about 15A.

    After connecting the controller the display showed an average of 77V and on the first day, this was successful in fully charging my low inverter batteries. (though there was an intermittent govt power supply).

    The problems started after the batteries became full and I started using my inverter. The battery voltage kept going down while my solar system din't work to give it any charge, even though the voltage continued to vary between 75V and 80V. I complained about this to the seller of my controller and he claimed that the panels should have been configured differently, i.e I should have configured it as follows -

    2 sets of 3, meaning that 3 solar panels will be in series thereby giving 72V and the two sets of 3 would be connected in parallel giving about 10A.

    I did as he said and the voltage I see on the controller is an average of 115V. I also see 75V and above even in the early light hours of 7am each morning, but the controller still doesn't charge the batteries constantly, it sometimes does so for seconds and stops.

    So my question is, if the solar panels are bad as the charge controller seller claims, will his controller still get the voltage it is getting, and is it possible to keep getting above the minimum voltage for the charge controller (70V) and not be getting current at all from the panels. Kindly help answer this, because it is confusing.
  • Wy_White_Wolf
    Solar Fanatic
    • Oct 2011
    • 1179

    #2
    Sounds more likely to me like your inverter/load is too big for the batteries/array to handle.

    More details are really needed on your system.

    Battery size and make/model? Solar panels make/model? Charge controller make/model?

    Simple VOC and ISC test of the panels should give you an idea if they are bad. Do you have a multmeter capable of doing these tests?

    WWW

    Comment

    • Sunking
      Solar Fanatic
      • Feb 2010
      • 23301

      #3
      Agree sounds like your whole system is way too small for that monster sized inverter you have. For a 5000 watt inverter @ 48 volts is going to require a panel wattage of 4000 or more watts, 80 amp MPPT controller, and a 1000 AH 3000 pound battery.
      MSEE, PE

      Comment

      • metobi1
        Junior Member
        • Apr 2015
        • 10

        #4
        Originally posted by Wy_White_Wolf
        Sounds more likely to me like your inverter/load is too big for the batteries/array to handle.

        More details are really needed on your system.

        Battery size and make/model? Solar panels make/model? Charge controller make/model?

        Simple VOC and ISC test of the panels should give you an idea if they are bad. Do you have a multmeter capable of doing these tests?

        WWW
        Originally posted by Sunking
        Agree sounds like your whole system is way too small for that monster sized inverter you have. For a 5000 watt inverter @ 48 volts is going to require a panel wattage of 4000 or more watts, 80 amp MPPT controller, and a 1000 AH 3000 pound battery.
        Thank you both for your responses, and sorry for not giving more info sooner, it turns out the charge controller was faulty as was found out by using another. Thank you once again for the help.

        Comment

        • Saipro
          Junior Member
          • Jul 2015
          • 2

          #5
          Originally posted by metobi1
          Thank you both for your responses, and sorry for not giving more info sooner, it turns out the charge controller was faulty as was found out by using another. Thank you once again for the help.
          I'm having the very same issue but from a Chinese company which is being dodgy on warranty claims despite the MPPT CC being well under warranty (2 years warranty, fault noticed 3 days into use; had spent 2 weeks in the box before unpacking to hook up since I had to wait for the delivery of the batteries).

          Do you know the details of the fault?

          Comment

          • PNjunction
            Solar Fanatic
            • Jul 2012
            • 2179

            #6
            Without any details it is hard to determine.

            I can suggest to make sure you are running the panels within the controllers voltage rating, and make sure you are following the hookup sequence properly. Typically that is attaching the controller to the battery FIRST, and the solar panels LAST.

            Comment

            • Saipro
              Junior Member
              • Jul 2015
              • 2

              #7
              Originally posted by PNjunction
              Without any details it is hard to determine.

              I can suggest to make sure you are running the panels within the controllers voltage rating, and make sure you are following the hookup sequence properly. Typically that is attaching the controller to the battery FIRST, and the solar panels LAST.
              Actually, I was asking metobi1 for the details of the problem with his charge controller. Regardless, thanks but I hook up in that prescribed sequence as that's what the manufacturer did recommend too. What I did notice the day the fault developed however is that the batte
              ries were fully charged before midday and I had full insolation till sundown. I however neither diverted the power nor switched to load mode. stayed connected to grid power instead. The next morning, it refused to charge the panels.

              Everything was fairly okay prior to than. That's all there really is to it

              Comment

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