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Air Conditioner 5-6K on 1000 Watt Inverter..

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  • Air Conditioner 5-6K on 1000 Watt Inverter..

    I was reading online abit but figured I'd ask the KNOWING/DOING on here..

    I have planned out a rough setup and would like to run a 9.7EER Rated 5K or 6K BTU Air Conditioner.. for say upto 6 hours during the peak hours in WEST TX.. (with a proposed 800-1000 watts of panels)

    I read the specs (from General Electric) on the AC units, and they say from 515 watts to 570 watts and 4.7amp - 5amp on the sheets.. and the yearly $ on the EER yellow tag says like $42 per year..

    I know there would be a proposed SURGE at startup and when the compressor kicks..

    I was initially proposing 2 T105's (200ah), and the Xantrex Prowatt SW1000 (Sine Wave Inverter) which can do 900watt and 7.5AMP continuous (with the max of 2000watt and 9.6amp..).

    The questions are:

    What type of run time in hours could I expect??
    Would going with 4 T105's (400ah) make this work longer?? and for how long??
    Al Z.
    1160 watts PV, 30.86 & -104.792, MidNite Classic 150, Xantrex Pro SW 2000, TS 30 Transfer Switch

  • #2

    Re: Air Conditioner 5-6K on 1000 Watt Inverter..

    Re: Air Conditioner 5-6K on 1000 Watt Inverter..

    Even with nothing else on it is doubtful a 1,000 Watt inverter will start the A/C. You're actually looking at a start-up surge that translates to at least 1800 Watts. With the usual efficiency losses, you can expect to fault the inverter with every attempted start.

    And a 12 Volt system is hopeless for such big current draws, never mind run time. That 5 Amp AC running current will be more than 50 Amps DC, and will flatten two T105's to dead in short order if they do survive the 150+ Amp start surge. Looking at it in the simplest (and least accurate) way:

    5 Amps @ 120 VAC = 50 Amps @ 12 VDC. 200 Amp hours - 50 Amps per hour = 2 hours before 50% DOD.
    That's not any run time at all, and it does not include inverter conversion efficiency, consumption, Peukart effect on the batteries, et cetera.

    This is a no-go.
    1220 Watts of PV, OB MX60, 232 Amp hrs, OB 3524, Honda eu2000.

    Ohm's Law: Amps = Volts / Ohms
    Power Formula: Watts = Volts * Amps

    Comment


    • #3

      Re: Air Conditioner 5-6K on 1000 Watt Inverter..

      Re: Air Conditioner 5-6K on 1000 Watt Inverter..

      So I would need a 2000+ watt continuous inverter and at least 6 T105's (would be 600ah total @ 12v)..

      I am looking at a Sunforce 2500 (Sine) for like $500.. or the Xantrex SW2000 (Sine) is $350..

      Then I can maybe get 4-5 hours??
      Al Z.
      1160 watts PV, 30.86 & -104.792, MidNite Classic 150, Xantrex Pro SW 2000, TS 30 Transfer Switch

      Comment


      • #4

        Re: Air Conditioner 5-6K on 1000 Watt Inverter..

        Re: Air Conditioner 5-6K on 1000 Watt Inverter..

        A/C and other things that use compressors can have a very high startup surge, as much as 4x the running amps. I doubt that either of those inverters mentioned will have the surge capacity to handle it.
        Northern Arizona Wind & Sun Forum & Website Administrator

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        • #5

          Re: Air Conditioner 5-6K on 1000 Watt Inverter..

          Re: Air Conditioner 5-6K on 1000 Watt Inverter..

          You can minimize the surge by cutting the Compressor off by turning the Temperature as high as it will go and let the fan start first by it's self, then cut the compressor in. Once you got it going it's the compressor cutting in and out with the fan on constant.

          The draw will over time will drop as you get the room temperature down the cycles will go down. There is a point that your better off to keep the compressor running all the time because the cycles are short and it'll draw more cutting in and out.

          I think Coot was a little generous with the 50 Amps @ 12v, mine pulls about 70 Amps.

          I have my fan on a " Delay on Make " timer cube and it will delay the fan start and a wall thermostat on a relay for the whole thing. The Fans on a A/C are big hogs by themselves.

          Comment


          • #6

            Re: Air Conditioner 5-6K on 1000 Watt Inverter..

            Re: Air Conditioner 5-6K on 1000 Watt Inverter..

            Originally posted by Blackcherry04 View Post
            You can minimize the surge by cutting the Compressor off by turning the Temperature as high as it will go and let the fan start first by it's self, then cut the compressor in. Once you got it going it's the compressor cutting in and out with the fan on constant.
            That was the startup plan.. fan 1st.. I found a G.E. unit with knobs for 3 speed fan and separate cool setting..

            The extra $100 for the Xantrex SW2000 may be the way to go then initially over my original SW1000 thought.. This is TX.. it isn't cool..
            Al Z.
            1160 watts PV, 30.86 & -104.792, MidNite Classic 150, Xantrex Pro SW 2000, TS 30 Transfer Switch

            Comment


            • #7

              Re: Air Conditioner 5-6K on 1000 Watt Inverter..

              Re: Air Conditioner 5-6K on 1000 Watt Inverter..

              I was giving numbers for "best case".
              Worst case: 5 Amps = start-up surge of 25 Amps @ 120 VAC. Convert to DC load and you get about 275 Amps all in one go. This would "flatten" 200 Amp hours of battery instantly.

              And that is a big concern. With the very high DC current the Voltage "apparent" at the inverter can drop below the minimum and the system will shut down rather than start the A/C unit. The system Voltage of 12 is probably a bigger problem than the load itself. On a 24 Volt system those concerns would be greatly reduced (137 Amps potentially). On 48 Volts you wouldn't need to worry (68 Amps potentially).

              Have you seen the thread about the mini-split A/C's? They have a soft start that almost eliminates this problem.
              Although I still wouldn't be keen on running one off 12 VDC. If you're thinking of swapping inverters anyway (and you need to to run that) maybe it's time for a system upgrade?
              1220 Watts of PV, OB MX60, 232 Amp hrs, OB 3524, Honda eu2000.

              Ohm's Law: Amps = Volts / Ohms
              Power Formula: Watts = Volts * Amps

              Comment


              • #8

                Re: Air Conditioner 5-6K on 1000 Watt Inverter..

                Re: Air Conditioner 5-6K on 1000 Watt Inverter..

                Coot, wasn't trying to get on your toes, mine does pull more than 50 Amps. I have been wanting one of those Dometic Soft Start units to test, but at $350.00 on a $90.00 A/C is hard to justify. a 13,000 but unit on a Honda EU2000. There is a video of it somewhere.

                http://escapeforum.org/index.php?topic=1282.15

                Comment


                • #9

                  Re: Air Conditioner 5-6K on 1000 Watt Inverter..

                  Re: Air Conditioner 5-6K on 1000 Watt Inverter..

                  I have seen that thread.. but I thought it was unfinished??

                  And the 2 part system kinda turned me off to it.. unless I read that wrong..

                  I did find this model for $729 though I am not sure if this what you mean..

                  Or did you mean this Sayno 0772??
                  Last edited by ywhic; April 13th, 2012, 10:38.
                  Al Z.
                  1160 watts PV, 30.86 & -104.792, MidNite Classic 150, Xantrex Pro SW 2000, TS 30 Transfer Switch

                  Comment


                  • #10

                    Re: Air Conditioner 5-6K on 1000 Watt Inverter..

                    Re: Air Conditioner 5-6K on 1000 Watt Inverter..

                    as the guys indicated you will find that between the high surge turn on and the low power factor that you would need a high power good quality sine wave inverter. the sw2000 is borderline with its capacity and it may or may not work for you as it's hard to say. this also means a much larger battery bank and pv system to feed it as the high draws would dip the voltage on a small bank shutting down the inverter even if run for short time periods. even running a refrigerator is a royal pain in their requirements and they are somewhat similar to a very low btu a/c unit (well under 5000 btu). this is something you should think bigger on for an off grid pv system or go with a generator. if grid tied then just supplement as best as you can with solar.
                    NIEL

                    Comment


                    • #11

                      Re: Air Conditioner 5-6K on 1000 Watt Inverter..

                      Re: Air Conditioner 5-6K on 1000 Watt Inverter..

                      Thank you.

                      I will test things out later this fall on my 2nd trip back to the 12x24 'cold cabin' (being built this week coming up)..

                      When I get back I'm gonna start ordering stuff up.. controller, inverter, wires.. panels/batteries will be last and more local to TX..
                      (still in PA right now)
                      Al Z.
                      1160 watts PV, 30.86 & -104.792, MidNite Classic 150, Xantrex Pro SW 2000, TS 30 Transfer Switch

                      Comment


                      • #12

                        Re: Air Conditioner 5-6K on 1000 Watt Inverter..

                        Re: Air Conditioner 5-6K on 1000 Watt Inverter..

                        albert,
                        you will also have the option of using a swamp cooler as, if i miss my guess, that area will have fairly dry air. swamp coolers use evaporation to help cool things and will have a fan to speed it along. no compressor could save you big on the power consumption. that item would be bought down in the midwest as the east is too humid to accommodate such a thing and therefore it is not usually available here in the east. the drawback is you need to keep it with water and in arid areas it could be scarce. not too sure of how much crud builds up either from high ppm values found in ground water. city water is high too, but not as high as many wells are.
                        NIEL

                        Comment


                        • #13

                          Re: Air Conditioner 5-6K on 1000 Watt Inverter..

                          Re: Air Conditioner 5-6K on 1000 Watt Inverter..

                          Originally posted by niel View Post
                          albert,
                          you will also have the option of using a swamp cooler as, if i miss my guess, that area will have fairly dry air. swamp coolers use evaporation to help cool things and will have a fan to speed it along. no compressor could save you big on the power consumption. that item would be bought down in the midwest as the east is too humid to accommodate such a thing and therefore it is not usually available here in the east. the drawback is you need to keep it with water and in arid areas it could be scarce. not too sure of how much crud builds up either from high ppm values found in ground water. city water is high too, but not as high as many wells are.
                          I used one when I lived in Denver and about every other season it required pad replacements because of build ups, and that was on utility water. They are a good solution if the air is dry enough.
                          Sticking it to the power company one watt at a time!
                          60 Ningbo Electric 175 watt panels and 12 Canadian Solar 180 watt panels with 2 PVP 5200 Inverters

                          Comment


                          • #14

                            Re: Air Conditioner 5-6K on 1000 Watt Inverter..

                            Re: Air Conditioner 5-6K on 1000 Watt Inverter..

                            Pretty dry area.. heres a picture of my actual 11 acres with 'yelllow tape'.. LOL

                            I'm 13 miles from the Rio Grande..

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Views: 1
Size:  156.4 KB
                            Al Z.
                            1160 watts PV, 30.86 & -104.792, MidNite Classic 150, Xantrex Pro SW 2000, TS 30 Transfer Switch

                            Comment


                            • #15

                              Re: Air Conditioner 5-6K on 1000 Watt Inverter..

                              Re: Air Conditioner 5-6K on 1000 Watt Inverter..

                              Ok, I've been there and done that, Lots of issues, but first My 1800 watt prosine inverter (has a 3000watt max capacity) runs my 5300 BTU AC just fine, and I've run it off of a hybrid 1400watt inverter (2800 or 3000watt surge) My setup is/was similar to yours in that I used 4 Golf cart batteries, originally I had @1000 watts of panels. I run a 24 volt system.

                              What I did was to build a 10x16 cabin with 13' height(sleeping loft), I built it in the shade, I built it knowing I would want to air condition it, so it has double pane windows and and 6" insulated walls, with 8 or 10" in the floor.

                              During the day after the batteries go into float I feel comfortable running the AC, The first hour may be a slight draw down of the batteries, as the Duty Cycle is 70-80% (the compressor runs 70-80% of the time) after the room is cooled off it runs30-50% depending on the outside air temps. I live in Missouri and heat typically runs with the sun, and we only hav 6-10 weeks of really hot temps. I normally work in the earlly evening and would run the AC on Energy saver for 2 hours and go to sleep, if I woke up due to it having warmed up too much I'd run the AC on timer for an hour and in the worse of times I'd run it again early in the morning.

                              The AC was sold by sears and was 10.3 rated, I see they have a 5200 with an 11 effiecency rating now. The fan comes on first in my unit and then a minute or so later the compressor kicks in, or if you have it on energy save the fan will turn off if your setting is above the room temp.

                              If you have shade... and a well insulated building.... It can be done...

                              ...in Missouri.



                              Original Array, while I added panels to adventually bring this up to 1600 watts (on the golf cart batteries) the batteries capacity is really the limiting factor, the larger array only let me turn on the AC earlier in the day while the sun was shining.

                              Attached Files
                              Home system- 20 - 200W Evergreen blems, 2 Classic Lites, E-Panel, 2 Prosine 1800 watt inverters, 800AH 24V forklift Batt, up and running 1 Classic Lite and 14 Suntech 185W in spare room.
                              Experience with Pulse/Trace PC250 Power Center, Original Rouge CC, 80-4/5watt 6v panels, Odds and extras,

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