How many amps do you need to run the AC? We are headed to a music festival next week, and have conflicting info as to what service we will have. We've been told both 20 and 30. (I've never heard of 20 amp service so hoping that was a mistake.) We have a 13500 AC with a hard start capacitor. Sorry if this is a repeat question - I searched the threads and didn't quite see the answer to my question. Thanks!!

perkc2 wrote:How many amps do you need to run the AC?Depends somewhat on the make / model of A/C you have but a 13,500 BTU typically would draw +/- 13 to 14 amps, a bit less if you run the fan motor on low. Assuming a nominal unloaded campground voltage of 120 vac, a not excessively long main service cable run to get to the post, and assuming you're using 10 gauge main service cable your A/C will start and run just fine on a 20 amp drop, common in many parts of the US but not common at all here in Canada. To use it though you'd need a 30 amp female > 15 amp male dogbone so you can plug into that 20 amp service. Given the choice though use the 30 amp drop as you'll have just that much more capacity for running other items in the trailer.

30 amp service will not be a problem.....as long as you do not run too many other things on AC at the same time such as microwave, water heater, hair dryer, etc. If you trip the breaker, just turn something off and reset the breaker.I can run my 15K A/C on 20 amp service as long as I do not run much of any thing else.

But don't be surprised if you have issues running the A/C on 20A. I'd certainly monitor the voltage.Many CG's have 20A plugs often with 30A and 50A on the pedestal.

I just driveway camped for 5 days , plugged into their dedicted 20 amp/110 house outlet... I ran my 15K AC and all my LED lights inside along with my Television at times... No problems..

How many amps to run AC | Good Sam Community

28 Replies

PaulJ2
Explorer
Jul 23, 2016
Amps for running an rv air conditioner figure about like the btu's. 13,500 btu's about 13 amp. 9,000 btu's about 9 amp. These are running amps though. Starting surge is about three times running amps but for about a second, max.
SoundGuy
Explorer
Jul 22, 2016
ksg5000 wrote:
Many would argue that 104 volts will damage compressor ... I personally would shut off my air conditioner if it dropped below 109 - question of risk assessment.

"Many"? :h I guess you would like TRC's low threshold voltage cutoff @ 102 vac even less. :p Clearly those who engineered Progressive Industries' EMS series wouldn't agree with those "many" you speak of either. :W
ksg5000
Explorer
Jul 22, 2016
SoundGuy wrote:
ksg5000 wrote:
Also - it's probably a good idea to get a kill a watt or some other method to monitor your voltage so you can shut off the air conditioner if voltage lags.

My Progressive Industries EMS-HW30C does this automatically anytime voltage drops below 104 vac, continues to monitor the incoming source, and won't turn power to the trailer back on again until voltage exceeds that threshold and only after a 136" delay to protect the A/C compressor. Wouldn't now ever plug into any source without such protection. :)

Many would argue that 104 volts will damage compressor ... I personally would shut off my air conditioner if it dropped below 109 - question of risk assessment.
SoundGuy
Explorer
Jul 22, 2016
Bumpyroad wrote:
I "assume" that you have a multi-function surge protector to protect if the voltage drops?

I can't speak for others but if it was important enough to me I'd add a voltage regulator to help maintain sagging voltage but it isn't so having my EMS simply disconnect power to the rig anytime voltage drops below 104 vac works just fine for me. :)
hohenwald48
Explorer
Jul 22, 2016
Bumpyroad wrote:
I "assume" that you have a multi-function surge protector to protect if the voltage drops?
bumpy

Most folks don't.

Does anybody know if somebody makes a similar device that can be left on when using an inverter (Honda etc) type generator?
hohenwald48
Explorer
Jul 22, 2016
Another trick when you are a questionable power source is once you get it running set the thermostat low enough so the a/c doesn't cycle. Like many have said, it's the start up that gets you in trouble. You should try to monitor the voltage. If it get under 110 you need to pay real close attention. Any lower and you can start having problems. Unlike people, when it comes to shore cords, fatter and shorter is better. :)
Bumpyroad
Explorer
Jul 22, 2016
I "assume" that you have a multi-function surge protector to protect if the voltage drops?
bumpy
SoundGuy
Explorer
Jul 22, 2016
ksg5000 wrote:
Also - it's probably a good idea to get a kill a watt or some other method to monitor your voltage so you can shut off the air conditioner if voltage lags.

My Progressive Industries EMS-HW30C does this automatically anytime voltage drops below 104 vac, continues to monitor the incoming source, and won't turn power to the trailer back on again until voltage exceeds that threshold and only after a 136" delay to protect the A/C compressor. Wouldn't now ever plug into any source without such protection. :)
ksg5000
Explorer
Jul 22, 2016
My 02. You can run your AC on 20 amps ... but not much else at the same time. If it were me I would make sure that your batteries are fully charged because your converter in charge mode with AC running might create issues --- also put the fridge on propane and don't run the microwave etc at the same time. Also - it's probably a good idea to get a kill a watt or some other method to monitor your voltage so you can shut off the air conditioner if voltage lags.
SoundGuy
Explorer
Jul 22, 2016
HGL wrote:
We have the 13.5 AC on our trailer as well. We have a 20A circuit at home for the trailer. Initial startup of the AC draws 18.2A and then settles at 13.8A.

Well yes and no. ;) As already mentioned the LRA (Locked Rotor Amp) rating for any of these roof mounted A/C units is several times higher, 60 amps not uncommon at all. Duration is quite brief so although you can't measure it with a DVM this doesn't mean it's not happening - it is, every time the compressor tries to ramp up to speed.