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jungleexplorer's avatar
Aug 29, 2014

Is my generator big enough?

I have have a Coleman 2500 watt generator and I am wondering if it will pull my rooftop AC on my 19ft travel trailer? My rooftop AC is a Duo-Therm Model: 57915-541. It does not say how many watts it pulls on the plate that I can find. What do y'all think?
  • jungleexplorer wrote:
    I know AC units have a start up and run amperage. They pull 30% to 50% more at start up then they do running. It is the start up that I am worried about. Most AC units, that I have seen, state what their start up and run amperage or wattage is. This one does not, or I have not found where it states it. That is really what I need to know.


    Right. I'm no ac guy but the ambient will matter too. I think the amp draw is much more when it's 95 vs 60 which is probably what I'm seeing when I tried mine tonight.
  • I know AC units have a start up and run amperage. They pull 30% to 50% more at start up then they do running. It is the start up that I am worried about. Most AC units, that I have seen, state what their start up and run amperage or wattage is. This one does not, or I have not found where it states it. That is really what I need to know.
  • You probably actually have about 2200 or 2300 watts. 2500 is probably surge.
    Generators will be rated in watts and your manual probably says that if you have a 13,500 btu ac it requires a 3500 watt gen. Many will run on less.

    They are saying that if you check your system voltage as the ac works you can see if the voltage drops too low.

    2300 watts divided by 120 volts equals 19 amps.
    If you can borrow a clamp on amp gauge it would be good to check amp draw. You want to see starting amps and amps as it cycles on and off with compressor head pressure.

    Remember that your converter and anything else on 120 v will add to the ac load. Put the frig, water heater on propane

    You dont want to run maxed out because it's hard on both pieces of equipment.

    I just checked my rig and the ac was pulling 5 to 6 amps but the ambient is only 60. I have seen it pull more but cant remember how much.

    Beg borrow or borrow a clamp on amp meter.
  • By "way low" he means 110volts or less. Voltage this low will cause long term damage to electric motors.

    Your a/c unit is a 13,500 btu unit. I do think your generator is adequate,just watch the voltage.
  • pianotuna wrote:
    Hi,

    Generators are rated in VA not watts.


    Well, it says 2500 watts on the label. Maybe they have a different standard in Canada.
  • Hi,

    Generators are rated in VA not watts. At low altitudes and with some air conditioners 2000 VA is enough. Others may not be so lucky. The only way to tell is to try it and monitor the voltage. If it dips way low, then it may not be a good idea to do it.

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