2013 PPV Tahoe battery drain

I believe there is a thread on this. My 2013 PPV Tahoe had a slow drag one warm morning to start. Then came the nightly drain from then on. My primary battery was throwing an occasional sulfuic stink and i thought initially it may have been the catalytic converter considering i have a oxygen sensor throwing my check engine light. Anyhow, i would go into town after jumping it off was no problem leaving it off for a good hour or 2 and crank right back up. I was reading up and watched a video and was said when parked for the night, make sure the battery has a good charge give it 30 min or more and pull the BCM fuse and put it back in before i had to leave . Well with doing that i still had to set out the ever so handy jump box .But since i pulled the BCM neither battery id trying to hold more then 8 on the DC tester. I was gonna do the one fuse at a time but to be honest im really tech tar. The alternator is new and ive taken it to have it tested took the alternator off the boyfriends ppv same outcome. Also i have noticed hearing the door lock actuator when the tahoe hasn't been moved all day. Any of your great knowledge and advice would be greatly appreciated

Sounds like parasitic draw. Video below describes it pretty well and steps to test for it. Going to need a few special tools.

Thanks for the video and reply. After making the post, i put the primary battery on a trickle charge for most of the day and popped the top on the secondary battery and it was bone dry. After getting acid replaced back into it and started it on a trickle charge i found that i didn't have as bad of a issue as i thought. Both batteries are new couldn't figure out why one was bone dry. Boyfriend did a swap with batteries unbeknownst to me. Once i put my battery where belong its back to good standing.