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??

Comments

  • CariboocootCariboocoot Posts: 17,615Banned
    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.
  • ywhicywhic Posts: 612Solar Expert
    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??
  • WindsunWindsun Posts: 1,164Solar Expert admin
    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.
  • Blackcherry04Blackcherry04 Posts: 2,486Solar Expert ✭✭✭
    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.
  • ywhicywhic Posts: 612Solar Expert
    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.

    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..
  • CariboocootCariboocoot Posts: 17,615Banned
    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?
  • Blackcherry04Blackcherry04 Posts: 2,486Solar Expert ✭✭✭
    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
  • ywhicywhic Posts: 612Solar Expert
    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??
  • nielniel Posts: 10,311Solar Expert ✭✭✭✭
    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.
  • ywhicywhic Posts: 612Solar Expert
    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).. 8)

    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)
  • nielniel Posts: 10,311Solar Expert ✭✭✭✭
    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.
  • solar_davesolar_dave Posts: 2,271Solar Expert ✭✭✭
    Re: Air Conditioner 5-6K on 1000 Watt Inverter..
    niel wrote: »
    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.
  • ywhicywhic Posts: 612Solar Expert
    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..

    Attachment not found.
  • PhotowhitPhotowhit Posts: 3,244Solar Expert ✭✭✭✭
    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.

    7.jpg

    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.

    8.jpg
    7.jpg 85.1K
    8.jpg 53.1K
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, ForkLift battery. Off grid for @13 of last 14 years. 1000 watts being added to current CC, @2700 watts to be added with an additional CC.
  • PhotowhitPhotowhit Posts: 3,244Solar Expert ✭✭✭✭
    Re: Air Conditioner 5-6K on 1000 Watt Inverter..

    I was working on my post... don't see a lot of shade out there....
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, ForkLift battery. Off grid for @13 of last 14 years. 1000 watts being added to current CC, @2700 watts to be added with an additional CC.
  • ywhicywhic Posts: 612Solar Expert
    Re: Air Conditioner 5-6K on 1000 Watt Inverter..
    Photowhit wrote: »
    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)

    $975+ is a little steep for me for the Xantrex ProSine 1800..

    What is the brand of the Hybrid 1400 Watt inverter?? Was it a PowerBright??
  • Blackcherry04Blackcherry04 Posts: 2,486Solar Expert ✭✭✭
    Re: Air Conditioner 5-6K on 1000 Watt Inverter..

    What I do with my A/C is I use the Generator for about 2 hrs before going to bed. Top up the batteries and Turn the A/C down as cold as I can get it ( Around 70 deg ). I have the thermostat knob marked at about 76 deg. When I shut the generator off and switch to the inverter I turn the knob up the A/C won't come back on till way up in the night, maybe 2:00 am and then it only runs a short period of time. You need to figure out how load shifting and power management works best for you. Sometimes I do the two hrs on the Generator early in the evening and shut it down for a couple hrs then less before I go to bed. Anytime your running the generator and your not using all the power you can it's a waste. Your Solar will fill you back in during the day.
  • ywhicywhic Posts: 612Solar Expert
    Re: Air Conditioner 5-6K on 1000 Watt Inverter..

    Rethinking the initial setup to instead go with 24v over 12v.. since an A/C I have learned (on here) will need it..

    1 MorningStar Pro 30 Amp Controller (both 12/24v) compatible. $130
    1 stackable 24v 2500watt modified inverter to 115/120v.. (thanks photowhit for the tips) $210
    1 single (to start with) 250 watt 24v Monocrystalline Panel.. 8.5Amp and 30.7V $379
    4 T-105 Batterys linked in SERIES.. or some similar GC batteries.. (800ah total)

    The panels I want cost about $100 more than the cheapy 140 watt ones I was eyeballing.. but there seems to be more power in 1 24v panel then 2 12v panels.. :blush:

    This initial setup will get me rolling with fans and such..

    If this sounds like a DO-A-BLE plan please chime in..

    I appreciate the help..
  • PhotowhitPhotowhit Posts: 3,244Solar Expert ✭✭✭✭
    Re: Air Conditioner 5-6K on 1000 Watt Inverter..

    As I said in my PM "...8.5Amp and 30.7V..." is not a 24V nominal panel, but a panel designed for grid connect or use with MPPT charge controller.

    Math on the batteries, 800 amps only if you use them at 6volts, as 2 in series and 2 pairs paralelled, 12 volts at 400 amp, as a 24 volt string of 4 batteries, 24 volts at 200 amps.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, ForkLift battery. Off grid for @13 of last 14 years. 1000 watts being added to current CC, @2700 watts to be added with an additional CC.
  • icarusicarus Posts: 5,070Super Moderators admin
    Re: Air Conditioner 5-6K on 1000 Watt Inverter..

    Coming late to the dance, but here is my two cents,,,

    I have a lttiile frigidaire 5k BTU unit I run very rarely. I run it on my eu1000 Honda genny. I sue the slow start method, run the engine on full throttle, no load, turn the fn on and let it spool if full for a few minutes, then turn the compressor on low. The Eu100 will barely start it,, but runs it fine. It draws ~550 wats running.

    My guess is that you are going to be REALLY hard pressed to get any meaningful run time off nearly any 12 v battery set up. Even if it would run it, my guess is that any inverter will drop out due to low voltge shut down first. You could start it on the genny, and the a quick switch to the battery while the compressor is still running, then leave it running full bore so the compressor never shuts off.

    Tony
  • ywhicywhic Posts: 612Solar Expert
    Re: Air Conditioner 5-6K on 1000 Watt Inverter..

    Photowhit..

    Thanks.. for clarifying..
    I found some locally available Grape Solar 190 Watt Monocrystalline panels rated at 5.25AMP and 36.2V DC.. @ $290/each..

    That also clears up the battery issue.. (I confuse easy).. so realistically I should have 2 banks of 4 (total 8*6v) and then I would be 400ah rated in total.. hypathetcially I could run my AC for like 3 hours and be about +75% left in the bank..
  • silvertopsilvertop Posts: 155Solar Expert ✭✭✭✭✭
    Re: Air Conditioner 5-6K on 1000 Watt Inverter..

    I would go with the swamp cooler in a heartbeat, we used one in
    colorado and could drop the temp from 80 to 69 degrees in about two hours in a 2000 SQ Ft. home. I wish I could run one in the NW. I would plan at least 2000 watt inverter 24 volt MIN.(with a good surge rateing) and plan on running off PV ,not batteries.....I am going to try this also but havent upgraded my inverter yet.
  • silvertopsilvertop Posts: 155Solar Expert ✭✭✭✭✭
    Re: Air Conditioner 5-6K on 1000 Watt Inverter..

    The newer swamp coolers dont use that much water, in our town in Gunnison Colorado water was like Gold. You learned not to waste a drop, and we did OK......Our well was 285ft down and another 100 ft. to our three story house
    coming from the mid-west this was a culture shock.....
  • PhotowhitPhotowhit Posts: 3,244Solar Expert ✭✭✭✭
    Re: Air Conditioner 5-6K on 1000 Watt Inverter..
    ywhic wrote: »
    That also clears up the battery issue.. (I confuse easy).. so realistically I should have 2 banks of 4 (total 8*6v) and then I would be 400ah rated in total.. hypathetcially I could run my AC for like 3 hours and be about +75% left in the bank..

    Right battery bank, but you'll need a minimum of 1000 watt array (panels) to support it.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, ForkLift battery. Off grid for @13 of last 14 years. 1000 watts being added to current CC, @2700 watts to be added with an additional CC.
  • 2manytoyz2manytoyz Posts: 353Solar Expert ✭✭✭
    Re: Air Conditioner 5-6K on 1000 Watt Inverter..

    I'm in hot/humid FL. Swamp coolers don't work here. So when the grid goes down, I drag out a 5000 BTU A/C unit. To make sure it works with my hardware, I did some testing.

    0402.jpg

    First wanted to make sure it worked with a Yamaha EF2400iS generator.

    With the fan on high, and the compressor engaged, draws almost 5A. It's rated at 600W, so the numbers are close.

    0403.jpg

    After a few minutes I shut it off, then immediately tried restarting it. This is the worst case scenario, and not what you should do. Restarting too fast can stall the compressor as the pressure in the system is still maxed. Ideally, you should wait several minutes, allowing the pressure to drop. This isn't an issue when allowed to cycle normally. I wanted to challenge the generator.

    0414.jpg

    This tiny A/C pulled over 18 AMPS starting current! My generator momentarily picked up RPMs, then dropped back to an idle.

    The Xantrex Prosine 1800W inverter performed equally, if not better.

    My intent is to use my 900AH battery bank at night for the A/C unit, and critical loads (fridge, some lights, small TV, computer, etc), and a combination of a 1000W solar array, and the generator with a 75A Iota charger, to replenish the energy used at night.

    I had no problem cooling the master bedroom, bathroom, and short hallway with this A/C unit during the middle of Summer when the central A/C failed. After ~20 minutes, the room cooled down and the compressor cycled off. The blower only draws 0.2A.

    I also agree a 1000W inverter wouldn't likely start it, or at least not restart it when there's a head pressure.

    If swamp coolers work in your area, great! If not, it's still possible to use a window shaker.
  • dhsoladhsola Posts: 38Solar Expert
    Re: Air Conditioner 5-6K on 1000 Watt Inverter..

    I've found that these window A/C's burn a little more juice after they've been running a while, than when they first start.

    If you have water, definitely go with an evaporative cooler!

    Example: It turned unusually hot here (103 F). And with my setup (see sig) I could barely run one 5k and one 6k BTU A/C's between 10:30 am and 2:30 pm with no other loads. And even then, I was pulling 1 to 2 amps from the batteries in addition to what the panels were putting out. Granted, compressors were running constantly, non stop...
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