I have a 2002 X5 3.0 that I have had to jump start on four occasions over the last 30 days. I had the battery tested and it's good (only 6 months old). When the car sits overnight there isn't enough power from the battery to start the car however, I can't jump it off and drive it for a while and it will start right back up. I do have an external Sirius radio but I unplug it for the power source so that can't be the problem. The car does have Nav if that system could be pulling the system down? Looking for help.

Thanks, Mark