I've got a 2010 2.0 TDCI focus with the keyless entry and start, a few days ago for some unknown reason the car battery died, needed the car the next day so removed the battery, charged it overnight, put it on the next morning, drove it about 30 miles, left it parked up for a few hours, drove it back with no issues.

Went to use the car a few days later and it was totally dead again, charged the battery for the next couple of days, went to use the car but it seems it's not recognizing the key fob, had to unlock the door with the key which set off the alarm, none of the buttons on the fob work with the car, I've not tried the fob battery yet but I changed it not that long ago and have not had any low battery warnings.

Can the fob just need reprogramming to the car? If so is it possible to do myself? Been looking around the web but can't seem to find much.