Greeks wrote:A strange one I heard from someone the other day. They had a dead battery on a one year old modern car. Turned out to be because they parked in their garage every night but didn't lock the doors. Apparently current may still be drawn (for some reason) if the doors are unlocked. Unlikely, but it could be worth testing the battery again with the doors locked? Yes, the electronics on some modern cars can stay powered up so you can open windows, have the radio on and all sorts of other stuff but power down gradually after the car is locked. Luckily my BMW doesn't do this as I always forget to lock it, it's often unlocked on the driveway for days at a time. ??) My Mum's Passat had a faulty radio which drained the battery when the car was left unused for a week.