When my women start running their morning grooming and breakfast appliances it is usually a tossup whether the 30 amp breaker in the RV or the 30 amp breaker at the power post is the first to go. They blow breakers in my house too, usually too much on a branch circuit, as in trying to blow dry under the heat lamps.
Time for a little "edumacation" on the subject of power management.
According to Champion a 3100i will handle a 13.5K and a 3400i will run a 15K A/C. So for those two models of generator, I would be tempted to follow the manufacturer's advice.
The only problem with that theory is that I am pretty sure that AC is on a 20 amp breaker or less; it may be on a 15 amp breaker. If the TT wasn't in the storage yard all wrapped for safe keeping for the winter I would go check it out. But I'd be willing to bet dollars to donuts the breaker ain't more than 20 amps.
I think the 3100 may do it and turn off the AC before starting the microwave.
On paper, a 2800W could even work. I could be tempted to try that out.
* This post was
edited 12/09/16 01:32pm by nickthehunter *
If it is the Coleman Mach series, the manufacturer recommends 3.6/4 KW, for the protection of the A/C from low starting voltages. Yes, the 15K goes on a 20 amp branch circuit, draws 14-17 amps running, but might double or triple that briefly while starting the compressor.
Hooked up to power, this is a surge and brief voltage drop. Hooked up to a conventional genset, this surge is handled by trading rotational energy for extra power, slowing the generator briefly. Inverter gensets, if large enough, might not even sag the voltage (if not running in economy mode). Some will overspeed to briefly supply more than the rated power. In either type, the protective circuitry in the generator has to allow the surge, and if sized too small the surge will prolonged and the generator more likely to disconnect or even shut down.
I know campers who have gotten away with using the Yamaha EF3000ISEB for a 15K A/C, while the EF2400IS (nominally 20 amps) couldn't handle an A/C that large. One brand might work while another might not, and within brands, different models of the same nominal size have different surge capabilities. In the smaller sizes, it is best to look for something offering a "boost" feature.
You could be right about the 2800KW, but if you made a mistake and it wasn't large enough you'll find ways to double joint your knees to kick yourself in the tail!
And the inrush (starting) current on any electric motor is generally THREE times the rated running amperage. It may only be for a nano second, but that could be the difference between "Ahhh" and "Ah CXXP"