How to replace car key battery Most key fobs have a little slot you can use to pop them open with a small flatheaded screwdriver, a butter knife or another key.

Like anything else relying on a battery, you car key fob can die—often at the worst time. Thankfully, these batteries are easy to replace.

So you have got a new 2007 Mini Cooper "R56" on order and your wandering about that complex key fob that comes with it and how to open the car if the fob battery dies.