When Generators won't start air conditioner

[gspman]

hi all ...newby here

Wife and i just purchased a 2019 "used" keystone 29RKS. Love it, along with the deal cama briggs 6800 WT inverter/gen set.
problem is it will not start either air con unit in the camper (indiviually) without popping breaker on genset. The unit (genset ) has 3 hours on it ?
the rear air con is a 15k unit and the front is a 13.5k unit ?

Ohms law i = P/v

6800/12 = 566 surge amps to start the air con ...whats not working here

Am i incorrect to think this gen set is not big enough ?

Please advise
SB