The CR series of batteries are the most common “coin battery” types used in most modern car key fobs in the past few decades. The most common car key fob battery is the ubiquitous CR2032 battery.
The “CR” before the numbers stands for two things. First, the “C” is for Lithium. The “R” is for round, the shape of the battery. Then next two numbers indicate the battery size. A CR2032 has a diameter (length across the battery) of 20mm, and a height of 3.2mm.
CR batteries a not rechargeable. A common rechargeable key fob battery is the VL2020.
Let’s take a look at each common battery.
Most common key fob batteries
Often used is larger, modern smart key fobs, the CR2450 is the largest commonly used key fob battery. It’s large capacity can handle years of passive connectivity such as on BMW‘s comfort access key fobs.