CMOS Battery | Button Cell CR2025/CR2032 Lithium Batteries

🔋 CMOS Battery – Overview

• Function: Powers the motherboard’s CMOS chip, which stores BIOS settings, system time, and hardware configuration when the PC is off.

• Common Type: CR2032 lithium coin cell (3V)

• Form Factor: Coin-shaped, 20mm diameter, 3.2mm thickness

• Voltage: 3 volts

• Capacity: ~220 mAh

• Lifespan: 3–5 years (can vary based on usage and environment)

• Compatibility:

• Desktop motherboards (standard CR2032)

• Some laptops use proprietary CMOS batteries with connectors

• Symptoms of Failure:

• Incorrect system time/date

• BIOS settings reset on reboot

• Boot errors or hardware misdetection