I didn't see where you said how old the original battery was? Probably covered by warranty and I think the cause of the problem should be found. Sometimes I travel a lot and if my car is not going to be used for a week or more, I put the Porsche sold charger on. Also, I think I saw in the manual that the car will go into a sleep if all locked up for a period of time--to "save" the battery. FWIW, my Land Rover dealer told me not to leave my keys in the Rover(as I used to) when in the garage. He said this would keep the electronics, computer, whatever, always "on".