As noted that fuse should be for the power jack. And yes you would have to disconnect the battery cable to keep it from draining. Or you could add a battery disconnect switch. I just disconnect the battery cables.
2017 JayFlight 28BHBE
2014 JayFlight Swift 264BH (Sold)
2007 GMC 2500 Sierra Classic Crew Cab LBZ Duramax / 6spd Allison