anytime the car sits for over 48 hours the battery dies. 2 shops have looked at it and cannot find out why. any ideas what is draining the battery?

you really don't need a mechanic for this test,do it yourself,copy and paste the link,watch video....... How to Test and Find a Parasitic Battery Drain … www.youtube.com/watch?v=zdIKNnwEjIs

Did either shop perform a 'parasitic drain test' as far as you know?