Any one have ideas on whey the battery dies after the car sits for 6 - 8 days without using. This has happened 2 times in the last 3 months after a trip. First time the car was locked. Got the car open but unable to start the vehicle. Called On-Star and towed to nearest dealer who updated programs and tested all batters of all OK. 7/4/2019 came home from a trip and again the car would not start. Called for a Jump Start (battery showed capacity at 25%) but no luck. Towed to dealer again today. Getting the car out of Park was a real joyful project. Love the car but very unhappy with this situation. Any one else having the same problem???