I have an RV Water Pump that operates on 12VDC and draws a maximum of 7 amps (from a deep-cycle lead-acid battery power source). The pump says to put a 10 amp fuse in the circuit for protection.

Class A motorhomes and smaller campers typically run on both AC and DC power. The former is your electrical hookup at the campground. It runs the energy-demanding thing like your air conditioner, ...