The converter supplies 12V DC system with battery and recharges battery.
The fridge s being run on electric heater element (120V AC) as is your microwave (M/W) and your water heater (cause you don't have propane hooked up).
Your fridge running when M/W is running has nothing to do with converter/DC system
You have a 120 AC problem.......probably loose wiring in your Main AC Dist. Panel
You could have a DC control circuit problem IF your fridge panel lights are going out when fridge turns off. Do the fridge panel lights work/stay lit??
