I see one of the specs lists 30 to 46 amps.

A pair of GC-2 batteries has ~220 AH They earned that capacity rating powering a 11 amp load for 20 hours, before battery voltage hit 10.5v, which is considered 100% discharged.

Loads higher than 11 amps will reduce the total available capacity of this pair of batteries. due to peukert effect.

So a new Healthy fully charged pair of GC-2 batteries rated at 220Ah capacity with that 11 amp load, will have 156Ah of capacity with a likely generous peukert number of 1.1.

So at 30 amps it would take a total of 5.5 hours of run time of the AC unit to 100% discharge that pair of GC-2 batteries, assuming they were indeed fully charged and healthy, and the AC was the only load, and the cabling was thick enough to not heat up passing those 30 amps.

How much the AC would actually run is dependent on the ambient temperature and the desired temperature and how much heat is being produced by living humans within, who are trying to stay cool.

If someone wants to play with different capacity batteries and different size loads with a peukert calculator:

http://www.csgnetwork.com/batterylifecalc.html
Most batteries spec sheets do not list the Peukert number. Odyssey AGM lists a 1.112 on their group 31. A peukert number of 1.11, opposed to 1.1, reduces the total available battery capacity of those GC-2s by another 5AH

The numbers above assume a 1.1 peukert number. the higher the number the worse it performs capacity wise under loads higher than the load at which it earned its capacity rating.

100Ah battery can provide 5 amps for 20 hours, ect.

The peukert number is generally higher on batteries with thicker plates designed for deep cycle usage, and gets higher as they age.