For my coach, I have 2 Viair 444C 12 volt compressors mounted in the basement running into a 3 gallon tank with a pressure switch that cuts them on at 160 PSI and off at 200 PSI. I chose the higher pressure compressors because I run 120 PSI in my tires, and compressors that cut on at 120 PSI or less, including the engine driven compressor, do not have enough pressure differential to air up my tires. However, with a 160 to 200 PSI source, setting air pressure is a breeze.
Gerald