I just got back from 5 weeks in southern India and was disappointed to have the new (one month old before I left) battery go down to such an extent that I could not get the front of my 2000 Boxster to open to charge it.
I tried running power through the lighter to give enough juice to open the front, but it was no go. I finally fished out the cable release and got the hood open to jump start the car. I was sure suprised that only 5 weeks would be enough to draw down an almost new battery, next time its the trickle-charger....
Ed