2012 Chrysler 300 Needs To Be Jumped Every Time

2012 Chrysler 300 (Base Model)

• Replaced the battery last year after it died.
• Within 6 months, the new battery also died.
• Took it to a mechanic:
  • Alternator checked and confirmed to be fine.
  • Mechanic suspected a bad battery connection.
  • Battery was recharged overnight.

Progression of the issue:

1. Car ran fine for about a month.
2. Then, if left undriven for 2 weeks, the battery would be dead.
3. Later, if left undriven for 1 week, has enough battery for my key fob to lock and unlock doors but not enough to start the car.
4. Now, even after driving:
   • If I shut the car off and try to restart it 30 minutes later, the car wont start without a jump.