StEdmund

After I'd replaced the battery in my key-fob, I didn't knowingly carry out any sort of re-syncing procedure - it just worked straightaway.

Mine does that if I am pressing the clutch down at the same time as I press the button. If I am not pressing the clutch down, it simply switches on the ignition; when I want to start the car, I press the clutch down and press the starter button again.

Thanks. My experience with button cells tells me that there can be a huge difference between no-names and branded batteries. I have also seen significant differences in performance between branded types. The battery in my 'main' key fob failed at 1yr11m while the battery in my 'spare', which is only rarely used, is still operating at 2yr1m (Panasonics).

What brand of replacement battery were you using, please? My original Panasonic lasted 1yr11m.

Why not weekly - just to be on the safe side? It's essential to keep a (good) spare battery in the car - it's what that little cubby hole is for. It is equally essential to do a 'dry run' first so that in the event of a battery failure, you know exactly what to do.