I recently went through an issue with my 12v battery (see Stranded at Snowbowl). While the car was at the service center they pulled out the main pack because the connectors were not opening and closing fully. This was explained to me that the main current carry connectors open and close when the car is on/off and they can get so hot they don't operate correctly. The service center fixed the issue and all is well, but can anyone explain these more, how they work, etc? I'm just curious. Interestingly, after the repair my car has several more miles of rated range at full charge.