11-13 amps is the usual a/c draw, with slight differences for a/c vs heat pump, 13.5k vs 15k btu rating, and age. However, each a/c has a momentary draw of 2x that each time the compressor starts, and that will typically trip the 30A supply breaker if one a/c is already running and the second one attempts to cycle on. If you could get the second one started somehow, you would have enough amps to keep it running, but usually they won't succeed in starting. Or at least not reliably. Might work 5 times and trip the breaker on the 6th.
2004 American Tradition; 2013 Buick Verano
Homebase in the Ocala Nat'l Forest near Ocala, FL