Greetings & Welcome!
I love those Ape vans…
Have you tried the system on shore power to make sure it works as expected?
Besides the wiring, as Axel mentioned, inverters can be finicky. They are often not up to the capacity they are rated at. I have read that larger loads should never exceed 2/3 of the capacity, and it looks like you’re over that.
Most of the food trucks, ice cream trucks, and road service trucks that I see around are either using a gas generator on the back bumper, or a Redi-Line generator inside. I’m not too familiar with Redi-Line generators, but they appear to be a battery powered, motor driven, electric generator, that puts out the equivalent of shore power.
Cheers!
"There are those who learn, and those who wish they had learned." ~ Good2Know