If like my 95' Trek, and if I recall correctly, if you leave the backup camera turned it also turns on the inverter, which will take down the battery. Without shore power, the red light on the panel in the galley should be off - unless the inverter is on. Red light = AC power from either shore or inverter.
Vince and Susan
2011 Tiffin Phaeton 40QTH (Cummins ISC/Freightliner)
Flat towing a modified 2005 Jeep (Rubicon Wrangler)
Previously a 2002 Fleetwood Pace Arrow 37A and a 1995 Safari Trek 2830.