Battery backup for swamp cooler ?

Discussion in 'Off Grid Living' started by Redi2, May 24, 2019.

  1. Redi2

    Redi2 Monkey

    We're anticipating our CA power company to shut power off for significant periods during critical fire season days. We have back up generator power.
    However, we'd like to power a Champion ASA50 swamp cooler overnight (8 hrs) so that we need not listen to the generator.
    Specs say it pulls as much as 11.4 amps. Truth be known I'm not sure how to read the spec label (see attached) .
    We have a Traveler 1500 watt inverter with one (1) deep cycle battery that performed adequately during the recent power outage for minimal evening computers and TV. I'm presuming the inverter would handle the cooler as well (at least if run alone) but my question is:
    How do I calculate how big a battery bank we'll need for an 8 hour run. We can power the cooler and recharge the batteries during the day with generator power.
    Thank you
    hitchcock4 likes this.
  2. techsar

    techsar Monkey+++

    A lot.

    11.4 amps @ 120 vac is going to be close to 114 amps @ 12 vdc. Multiply that by 8 hours is 912 a/hr...but for most batteries, you don't want to go below 50% charge. So 1824 a/hr of storage capacity. Thats 19 100 amp-hour batteries.

    That is a lot of charging amperage.

    You're also pushing the inverter pretty hard...1368 watts, not counting startup surge demand.

    ETA:I have a mini split ac that only draws about 2 amps @ 220 vac...that runs off of the solar system. That's roughly a third of what you say the swamp cooler draws....something is wrong....
    Last edited: May 24, 2019
  3. Yard Dart

    Yard Dart Vigilant Monkey Moderator

    Welcome to the Monkey!!
    Gator 45/70 and sec_monkey like this.
  4. Cruisin Sloth

    Cruisin Sloth Special & Slow

    Attached to what ?
    Tech got it correct , your going to buy sleep plugs and run the gen set
  5. ghrit

    ghrit Bad company Administrator Founding Member

    11 amps AC sounds REALLY high for a swamp cooler pump and fan. Might want to have another squint at the nameplate for a double check or Sloth is right, buy earplugs.

    Last edited: May 25, 2019
  6. sec_monkey

    sec_monkey SM Security Administrator

    git a kill-a-watt and find out fer sure
  7. Ura-Ki

    Ura-Ki Grudge Monkey

    Run the Genny and buy fuel, its cheaper and you can get more hotel load at the same time! If you can hear the Genny, you can/should build an enclosure for it amd park it away from your sleeping area!

    Welcome to the Monkey Tree, have a swing through the branches!
    Zimmy, snake6264 and sec_monkey like this.
  8. Thunder5Ranch

    Thunder5Ranch Monkey+++

    11.4 amps sounds about right for a mid size swamp cooler. They range from 1amp for the small units up to 25amps for the big units. So yep get your ear plugs or add some battery capacity :)

    To limit generator noise a enclosure is a good solution. I run a 13,000 watt generac and 8700watt predator on my truck at farmers markets and shows and they are LOUD. So I built side boards, put a thick rubber bed liner in, and direct the sound up and out the back with the tail gate down. at 28 feet from the truck bed to my stand all we hear is a low hum. The vendors that set up 10 and 20 feet from the truck bed have no problem talking to or hearing customers at normal conversation levels. On the back side of the truck bed however it is so loud you can't hear yer self think. Recently switched the Diesel generator for the house and farm back up power to a 30kw Generac Propane burner and get almost zero sound from it. Might consider one of the smaller propane burners for back up if quiet is important. The honda quiet run gas jobs are good but but not much bank in the Watts/amps area for the buck IMO.

    I run the two on the truck because they get abused on the beautiful Southern IL pot hole filled roads and between the two, I have $1500 into them. So I am not tearing up a $5000-$10,000 generator driving around. And a couple hundred bucks of lumber, bolts, and a bed is a lot cheaper than a portable quiet run generator.
  9. HK_User

    HK_User A Productive Monkey is a Happy Monkey

    The rate you provided is for high speed, I suggest you check for the low speed amps and see if you can live with that.
    OTOH, a small refrigerant based unit in the correct area may be a better alternative as the reduced humidity will provide a more comfortable environment for sleeping and will draw less amps on average as it will cool to what you set it and will cycle on and off so you need to know your average run time and current draw.
    Gator 45/70 and sec_monkey like this.
  10. oldman11

    oldman11 Monkey+++

    I have a Honda 2200 that I run my house on. Two deep freezers,one refrigerator,the lights and tv. It seems to have no problem except when wife drys her hair or turns the microwave on. I know it’s not supposed to but as long as the freezers donot try to come on at the same time I’m ok. Starting amps is what gets you. My diesel gen quit after one day and I ran my whole house on the Honda gen for three days.The diesel was way too loud so when it quit I gave it to a poor family for their house. Now my house is old and has a 65 amp main breaker for everything including the main air conditioner. I did not try the air conditioner with the Honda as I knew it would be overloaded. The Honda ran on a twenty amp breaker and never tripped. I’m going to buy another Honda so I can run two together. We use low energy lights in everything and have gas for cooking and hot water.
  11. oil pan 4

    oil pan 4 Monkey+++

    Get a kill-a-watt meter and see how much it really draws while using the power inverter.
    Until then it's just a guess.

    You have to use the inverter to get good numbers because those junk traveler inverters put off square wave power which is inefficient for motor running applications. So it will draw more amps than if it were plugged into grid power.
    Last edited: May 25, 2019
  12. Cruisin Sloth

    Cruisin Sloth Special & Slow

    aaand then on Shore power and see the difference !!!!!

    Then you know the inverter is shit !!!
    Gator 45/70 and Thunder5Ranch like this.
  13. Redi2

    Redi2 Monkey

    Thanks for the responses.
    I checked the Swamp Cooler tag (had to use phone camera to see it) It's 1/2 hp 8 amps & the pump is 1.2 amps. Another essential is the Air Purifier = 1.1 amps.
    So, I'm hearing the general observation that the battery bank idea is impractical. We do have an AC unit available, so I'll check the specs on that. However, I'll explore the genset route. Believe it or not, there is already a manual transfer switch installed in this cabin. I'll have questions about that, but will make a different post.
    Thank you
  14. ghrit

    ghrit Bad company Administrator Founding Member

    Bear in mind that starting inrush current is way over running current. You ARE headed the right way by not trying go battery. Yet.
  15. BTPost

    BTPost Stumpy Old Fart Snow Monkey Moderator

    One thing to consider, is to look at using the Genset to power the startup loads, and then let the Inverter/Battery run the system, and see how that would extend you battery time..
  16. Cruisin Sloth

    Cruisin Sloth Special & Slow

    14 amps run ,X 120Vac =1700 Watts , WAY 2 high still IN my world .
    Mini split uses 240-430 watts for 1600BTU
    techsar and sec_monkey like this.
  17. arleigh

    arleigh Goophy monkey

    Here in southern California the climate has really changed and so we have not had to run the swamp cooler yet. but it's been a humid cold so it's like an extended winter.
    If I though I was going to have to run cooling on DC ,I would build my own swamp cooler using DC motors and battery bank.
    For my chickens during the hot summer months I would drip system water on a rag and use a computer fan to blow from it . they'ed stand there with wings open and cool off ..
    If it get's hot this summer I'll take pictures.
    oldman11 and HK_User like this.
  18. DKR

    DKR Raconteur of the first stripe

    a passive cooler tower
    is popular in the desert SW. As part of a whole house system, it saves considerably on heating/cooling costs

    These are also very low energy-use systems.
    Merkun likes this.
  19. oil pan 4

    oil pan 4 Monkey+++

    Refrigeration sur conditioning uses a lot more power than a swamp cooler.
    A small window unit uses around 500 to 600 watts.
    For a swamp cooler to use that much power it would have to be pretty big.
  20. Cruisin Sloth

    Cruisin Sloth Special & Slow

    DC inverters Mini splits are the way since 2005 !!
    Seer 22+ is for cooling
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