You may not get the a/c to start on anything less then 3-3500 watts.
Lots of folks have used paired Honda 2000 watt gen sets. That starts to get expensive with so many other decent ones now already at 3500 and the savings will pay for a 'lifetime' of gas.
There's a watt draw chart on this - accurate or not, a place to start:
https://www.ramsond.com/wattage-chart/