Hi,
A 13500 air conditioner will draw between about 1200 and 1900 watts, depending on the ambient temperature. 1900 REALLY pushes a 15 amp-shore power outlet. Maximum continuous draw should be 80% of full capacity or 1440 watts.
Watch out for voltage drop. I get uncomfortable below 109 volts and I use an alternative source at 107 volts. I do have a hybrid inverter, so start up loads get supported.
I did have a 30 amp breaker flip off at a campground with only the air conditioner running last summer.
