What type of 3kw genny do you have? Is it an inverter type like a Honda, which throttles down when there is no much load or is it a screamin demon that is running at full speed regardless of load?
Also if you are in need of a new converter you might want to consider 'marinising' your trailer & do it the way boats are set up with a 3 stage smart inverter/charger or at least a 3 stage smart charger. This eliminates the cheap & nasty single stage converter/charger. RV builders don't do it this way because, well, it costs more but you will get longer life out of batteries with a smart charger. The better smart chargers have a controller so that charging levels can be set depending on the size & type of battery bank.
Mine runs like a boat. All 12V needs are taken from the battery bank. The smart charger replaces as needed at the rate needed.
