I recently experienced a dead battery on my 2004 XC70. This happened\nfirst thing in the morning after being parked in my driveway\novernight. Battery seemed to be completely dead - no dome lights, no\npower seat adjustment, no click when attempting to start the vehicle.\nThe only difference on this night from the other 30 or so days that I\nhave owned the car is that the key was inadvertently left in the\nignition over night. Ignition was in the OFF position and no doors\nwere left open. I was able to start the car after charging the\nbattery for approx one hour and everything seems normal since then.\nAny ideas what caused this?