Run for an hour with, and an hour without, the 12v blower. See if it makes a difference; it`s way cooler in my ER if run.
Good design or good fortune, the exhaust intake is right above the eutectic refrigeration compressor. Exhaust fan on,the fridges cool a lot faster.
I think the fan draws around 15A. Running mains there are plenty of amps,pulling down fridges at anchor using the genset I run the battery charger.