Hi all....

How often do we need to replace the fob battery in our 4th gen Minis, what is the procedure and more.

The fob in our 4th gen cars has a lot more demand on it due to the many functions of our Minis.

For example...

We’ve been getting some really cold nights, so I keep the Mini on the NOCO charger whenever I’m not driving it, sometimes for a few days.
The charger is pretty simple...a green indicator light means the battery’s full and just being maintained, red means it’s actively charging.
What’s funny is it’ll sit there on green, but when I walk into the garage with the fob in my pocket, it flips to red.
Apparently, the car wakes up enough systems when the fob gets close, basically getting ready for a drive, that it pulls just enough power to make the charger kick back into charge mode.
These systems...digital display, heads up display, radio, etc., stay powered up for about 4 minutes or more.

This is the reason for needing regular battery changes on these fobs....

Of course, this is covered in the manual, but here is a brief 'how to' post I think covers all the questions regarding the fob.
I printed this out and keep it in my glove box for quick reference...

F66 Key Fob Battery Type & Replacement
• Press the small release button on the side of the fob and remove the back cover of the remote.
• The battery is exposed in a holder.
• Replace with a CR2032, positive side facing out.

The F66 key fob contains an emergency key inside the remote
• Press the small release button on the side of the fob, push down the key side cover and then slide it out.
• Pull the metal key out.
This key is used for mechanical entry only — not for starting the car.

How to Unlock the F66 When the Fob Battery Is Dead
Even with a dead fob battery, you can still get in.
1. Remove the emergency key.
2. On the driver’s door handle, look for the hidden key slot (MINI hides it under a small cap or trim piece).
3. Insert the metal key and turn to unlock.

How to Start the F66 When the Fob Battery Is Dead
MINI uses an NFC backup start system on the F66 (same as late F56 models).
1. Sit in the driver’s seat with the dead fob.
2. Hold the fob against the steering column or against the start/stop button area (MINI places the NFC coil there).
3. Press the Start/Stop button with your foot on the brake.
4. The car will recognize the fob even with a dead battery and start normally.

• If the fob is weak but not dead, the car may warn you with “Key not detected.”
• The F66 will still start if the fob is physically inside the cabin, even with a nearly dead battery.
• Always replace the CR2032 with a quality brand (Panasonic, Energizer, Duracell).
• If the fob ever becomes unresponsive after a battery change, re-seat the battery — the holder is tight.

Isn't AI wonderful!
Hope this helps.....