Here is another possibility. The battery should have been charged when driving however with my first TV (2004 GMC Sierra 1500) there was a fuse that had to be installed in the fuse block to allow the battery to be charged while driving. It was a 40A fuse.
Not sure how long your rig was actually parked but it would be interesting to know what the parasitic current draw is. Then it is simple math to determine how long the battery will last without being charged. Other than the booster, the other draw is the CO detector.
2016 Chevy Silverado 2500HD Duramax LTZ Z71 Extended Cab, Long bed
2012 Dodge Ram 1500 5.7L Hemi (with K&N Air Intake) (traded)
2012 Rockwood 2109S (Sold)
2014 Cougar X-Lite 21RBS