Does the 12 V output also have a limit like the 230 V socket (300 W)?
Could the 12 V output be used to operate a compressor cooler with 1800 W starting current?
I can't answer your question exactly. I have the Dometic CFX3 cooler (40l) on my Yeti 500x and it works without any problems. But I don't think it needs 1800W...