How long until battery dies when parked?

When I was a kid, everybody left their keys in the vehicles. If someone needed it moved, they got in and drove it.

 

At least, that does put a bound on your age. To the era when all vehicles had keys.

 

Perhaps I am just cheap, but I would find it simpler to simply leave the battery corner partially disassembled, the back seat down, and the negative lead disconnected.

The hatch will not open, but a quick crawl to the back is all that is needed to stick the negative terminal into it's hole. Then the hatch will open and the remainder of the housekeeping can be done from the back.

Expect to lose presets though, like radio stations.

 

Or,
a disconnect switch. But that wouldn't solve anything if the battery were discharging itself internally.

Personally, I'd use a battery-maintainer if I planned to leave it for more than 2 weeks.

 

SWMBO left her Gen 2 (with 4 year old OEM battery) for 3 weeks and it started no problem.

 

I think it depends on the type and condition of the battery. Some will go dead in a week without being connected to anything.