Not sure how my Boxster is set up. I have the smoking package and use the lighter socket for charging with my Porsche Charger. Often, after not driving for nearly a week, I will plug in the charger to maintain the battery without ever having started the car. I do not lock the car up and the charger works as it should without turning itself off. Now it has been on charge and covered up since Nov. 17th, unlocked, and working fine. I still think there is something about the socket and the Porsche charger plug that is different than the Ctek plug. It looks to me that a red plastic piece on the Porsche charger plug circumvents a circuit in the lighter socket, and avoids the auto shutoff function. JMHO