It is my experience that whenever I use the OBC functions to measure voltage, the alternator output is usually 14v or a little above even at idle.
It's just one car's experience, but it would indicate that your car is not charging with a healthy amount of power. And I think it could be a less than perfect battery or the alternator. Of course it could be just the voltage regulator if you wanted to try to economize.
Just for a check, do you turn everything off when you do this test, including the HVAC system completely off?
This would not cure what ails you as you still would have that parasitic drain.
Last edited by GoForthFast; 01-29-2013 at 10:51 PM.