2016 Chevy LTZ Battery dies constantly

In a late model vehicle, a battery will only last about 2 weeks if it is fully charged before engine shut down, and that is if it is a really good battery, most only make it a week before they are too low to start the engine. If the vehicle is going to sit any length of time you need to use a battery maintenance charger. Most are house current and need plugged in but there are a few Solar chargers that work as long as you have some sun. I have a 2013 and even with a brand new battery, fully charged it only lasts 8 days if I don't start it and let it run or drive somewhere. I have had it checked for excessive battery draw but it comes back as all clear. So, I have a small maintenance charger that I hook up when it just sits. HTH

You also don't want to disconnect the battery to try to save the battery. The computers need to be powered up at all times. If they lose power the computers will need to be reprogrammed by the Dealer. If you can't hook up some kind of battery tender, as Gene said, then you'll have to run the vehicle to keep the battery charged. About once a week, especially in the colder months should be sufficient. Also, you can check your owner's manual and see if it talks about "vehicle storage". Jim