Wow, The amount of false information being posted here on this topic is unbelievable. ...
As a side note on this one, when I first got my Colorado I had this problem. My BCM was not going to sleep and was drawing excess power while parked. My research found that the GM design point is the system must draw less than 20 ma. (.020 amps) when shut down and the vehicle must be able to start after being parked for 30 days.
Nice information on the 30 days.
I pretty much agree with everything you stated, but I would also add a poor ground connection to be another possible culprit. This may actually be considered as one cause of your poor charging, but it could manifest itself in other ways while still allowing a good charge to the battery.
I had a short one time in a circuit and I was able to basically disconnect everything until I found the short. With these new fangled vehicles, I am not sure I would know where to start on that task.
2015 Canyon SLT, Copper Red, 2WD, CC, SB, V6, Tow, blk leather, factory spray liner, safety pkg, generic roll up bed cover.