In short,
Porsche will not replace a dead battery under warranty if you drive under 12K per year.
If you let your Box sit, your battery will die.
The car will NOT charge up a dead battery by driving it 30 minutes. That is only a 2 AMP charge for 30 minutes and that will not do it.
Buy a battery charger (at least 10 AMPS) and charge battery fully. Then, see if it will hold that charge fully. If not, the battery is shot and you need to replace it.
If you need a battery, pick one up at Costco for under $50.
Then, buy a battery tender if you are still going to drive only 6K per year.
Good luck!
