Wish to run my Room Air-Conditioner on solar during day time

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  • digimart
    Solar Fanatic
    • Nov 2011
    • 101

    Wish to run my Room Air-Conditioner on solar during day time

    Am thinking of using solar power to run my room Air Conditioner during day time.

    Have a 18000 BTU ( 1.5 tons ) split air-conditioner runs on 220V AC, 50Hz. At start it draws a 30Amps current for few milliseconds, and then it comes to 12 Amps for few seconds, and then after say 15 to 20 seconds its current requirement comes to 8 Amps.

    My idea is to find some soft-starter or a VFD ( Variable Frequency Drive ) so that I am able to nullify the starting torque current of the air-conditioner. And after its installation, I hope then I just have to worry for 8 Amps regular current requirement only.

    This 8 Amps of current needed makes power requirement of my A/C 1800 Watts.

    If I install solar panels of 2500 Watts, and a MPPT charge controller , then I guess, that I be able to have sufficient power to run my A/C during day-time for 6 to 7 hours.

    Now I come to question about battery costs. This cost is high, and I wish to by-pass this cost.

    Upon installing a Soft-Starter / VFD to the air-conditioner. And having 2500 Watts panels, a MPPT controller, and an off-grid Inverter ( no batteries connected ). Would I be able to run the Air-Con during 5 to 6 hours a day ?

    Please comment on the above.
    [B]Omar S Chaudhry[/B]
    DigiMart
    Lahore
  • parish8
    Junior Member
    • Feb 2014
    • 26

    #2
    you could replace your unit with one that has a inverter and is variable speed built from the factory. it would likely be more efficient and have a lower start up current. if i had a way to measure the start up current on these things i would measure one for you but i only have a basic clamp on meter and i think it would miss a quick spike if there was one.

    I am running a couple of these https://www.goductless.com/LG-Air-Co...&trail=1004:LG

    and one of these in my garage https://www.goductless.com/Mitsubish...004:Mitsubishi

    the indoor fan, the compressor and the outside fan all are variable speed.

    with your set up i would be concerned a soft start might not get it started. if there was any residual pressure from the previous cycle it is going to take some power to get it spinning. i am not a hvac guy and do not fully understand how they work.

    Comment

    • digimart
      Solar Fanatic
      • Nov 2011
      • 101

      #3
      Thanks Parish8
      I would like to use the exisiting Air-Conditioner, rather than purchasing a new Inverter type A/C.

      Lets hope I able to get more information and guidance, and able to achieve this target.




      Originally posted by parish8
      you could replace your unit with one that has a inverter and is variable speed built from the factory. it would likely be more efficient and have a lower start up current. if i had a way to measure the start up current on these things i would measure one for you but i only have a basic clamp on meter and i think it would miss a quick spike if there was one.

      I am running a couple of these https://www.goductless.com/LG-Air-Co...&trail=1004:LG

      and one of these in my garage https://www.goductless.com/Mitsubish...004:Mitsubishi

      the indoor fan, the compressor and the outside fan all are variable speed.

      with your set up i would be concerned a soft start might not get it started. if there was any residual pressure from the previous cycle it is going to take some power to get it spinning. i am not a hvac guy and do not fully understand how they work.
      [B]Omar S Chaudhry[/B]
      DigiMart
      Lahore

      Comment

      • Wy_White_Wolf
        Solar Fanatic
        • Oct 2011
        • 1179

        #4
        Originally posted by digimart
        ...Now I come to question about battery costs. This cost is high, and I wish to by-pass this cost.

        Upon installing a Soft-Starter / VFD to the air-conditioner. And having 2500 Watts panels, a MPPT controller, and an off-grid Inverter ( no batteries connected ). Would I be able to run the Air-Con during 5 to 6 hours a day ?...
        NO

        1. No battery bank for the charge controller to set it's output voltage to.

        2. If you can get past the charge controller the inverter will shut down everytime a cloud goes over due to low power of the array. Even a bird flying over would shut it down.

        WWW

        Comment

        • Naptown
          Solar Fanatic
          • Feb 2011
          • 6880

          #5
          Originally posted by Wy_White_Wolf
          NO

          1. No battery bank for the charge controller to set it's output voltage to.

          2. If you can get past the charge controller the inverter will shut down everytime a cloud goes over due to low power of the array. Even a bird flying over would shut it down.

          WWW
          I agree with WWW
          NABCEP certified Technical Sales Professional

          [URL="http://www.solarpaneltalk.com/showthread.php?5334-Solar-Off-Grid-Battery-Design"]http://www.solarpaneltalk.com/showth...Battery-Design[/URL]

          [URL]http://www.calculator.net/voltage-drop-calculator.html[/URL] (Voltage drop Calculator among others)

          [URL="http://www.gaisma.com"]www.gaisma.com[/URL]

          Comment

          • Robert1234
            Solar Fanatic
            • Nov 2012
            • 241

            #6
            Maybe a dumb question, but since you appear to already have power, why don't you just grid tie the solar? Same net effect.

            Comment

            • russ
              Solar Fanatic
              • Jul 2009
              • 10360

              #7
              Originally posted by Robert1234
              Maybe a dumb question, but since you appear to already have power, why don't you just grid tie the solar? Same net effect.
              His problem is power failures - in that part of the world some locations enjoy virtually a daily off period or rolling blackouts.
              [SIGPIC][/SIGPIC]

              Comment

              • digimart
                Solar Fanatic
                • Nov 2011
                • 101

                #8
                Originally posted by Robert1234
                Maybe a dumb question, but since you appear to already have power, why don't you just grid tie the solar? Same net effect.
                daily power cuts are from 8 to 16 hours a day
                [B]Omar S Chaudhry[/B]
                DigiMart
                Lahore

                Comment

                • digimart
                  Solar Fanatic
                  • Nov 2011
                  • 101

                  #9
                  Thanks for your inputs.
                  So it seems that, all I can do for time being is that if I install a VFD, I be able to cancel the starting torque of the air-conditioner, and then I could get hold of a usual Inverter + battery bank + controller, and connect my Air-Con with the same.
                  As there be a VFD , so i be needing inverter with lesser power, and battery bank size would be less too.
                  [B]Omar S Chaudhry[/B]
                  DigiMart
                  Lahore

                  Comment

                  • Sunking
                    Solar Fanatic
                    • Feb 2010
                    • 23301

                    #10
                    Real simple, you need batteries. Not going to happen without them.
                    MSEE, PE

                    Comment

                    • paulcheung
                      Solar Fanatic
                      • Jul 2013
                      • 965

                      #11
                      Just get 4 cheap 12 volt batteries, you are not use them to power the AC, just use them to turn on the inverter and keep it on.

                      Cheers.

                      Comment

                      • David35
                        Junior Member
                        • Aug 2014
                        • 1

                        #12
                        Your plan is good but amperes can never be same air condition or air purification units. It is about to 25 to 30 in the start but in the running it came to 8 9 10 11. It never be constant at 8.
                        Last edited by SunEagle; 06-15-2016, 01:11 PM. Reason: removed link
                        be extra ordinary..

                        Comment

                        • russ
                          Solar Fanatic
                          • Jul 2009
                          • 10360

                          #13
                          Originally posted by David35
                          Your plan is good but amperes can never be same air condition or air purification units. It is about to 25 to 30 in the start but in the running it came to 8 9 10 11. It never be constant at 8.
                          Meaning?
                          [SIGPIC][/SIGPIC]

                          Comment

                          • Sunking
                            Solar Fanatic
                            • Feb 2010
                            • 23301

                            #14
                            Originally posted by David35
                            Your plan is good but amperes can never be same air condition or air purification units. It is about to 25 to 30 in the start but in the running it came to 8 9 10 11. It never be constant at 8.
                            If you cannot baffle them with your Brilliance, then dazzle them with BS.
                            MSEE, PE

                            Comment

                            • russ
                              Solar Fanatic
                              • Jul 2009
                              • 10360

                              #15
                              Originally posted by Sunking
                              If you cannot baffle them with your Brilliance, then dazzle them with BS.
                              As I lack in brilliance I have to go the BS route!
                              [SIGPIC][/SIGPIC]

                              Comment

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