I have a 2008 3.0 litre petrol XF. I had not used it for 2 days, tried to unlock it with the smart key but nothing happened. Thought the smart key battery was naff so replaced it with a new one but it still wouldn't unlock the car. An ex RAC Mechanic friend suggested it maybe the car battery (I had a new battery fitted a year ago). I then charged the battery overnight but still have no power. I have checked the battery leads which are all fine. Does anyone have any suggestions please?