Heron 3 A/C

Hi can anyone tell me first hand if a yamaha EF2800i generator will run a heron3 a/c in a 2003 coromol pop top, I have tried a honda eu2i and a kipor 2.6 but the honda would only start up and run/cycle on full throttle, the kipor struggled more than the honda to start up so my next option is the yammy 2.8 over the 2.4. Also in my vans power supply is a factory tranformer/ 3 stage 6 amp battery charger (1 unit ) I would like to replace it with a smart charger as I am running a 120ah agm & a supercharge 100ah deep cycle batteries, can I just replace it with a 30amp smart charger which will charge multiple batteries in one RV also states that it can be used as a power supply while still connected to the battery will this do the same job as the transformer? the van has 12v lights, CD player, and a 12v/240 90lt Engel fridge/freezer. Coromol told me that when using more of the lights less charge will be going to batteries. I am not sure how the full system works, any advise would be great.
Cheers Lyle