Do you leave the headlights in the on position all the time as I do and let the timer turn them off? Do you press the lock on the remote the second time and listen for the horn beep to verify the doors are closed? If the headlights are in the on position and a door is not completely closed the headlights will not time out and turn off and they definitely will kill the battery over night. Since you have the same problem on two different vehicles I would be looking at all operating procedures.