CMOS Battery: Benefits and Capacity Explained

A CMOS battery, also known as a coin cell or button cell, is a small battery commonly used to power the CMOS (Complementary Metal-Oxide-Semiconductor) memory on a computer’s motherboard. Here are the advantages of using a CMOS battery:

Advantages of a CMOS Battery

1. Non-Volatile Memory Power: The main job of a CMOS battery is to continuously power the CMOS memory. This memory stores important system configuration information, like the date and time, BIOS/UEFI settings, and other system parameters. This ensures that this crucial data isn’t lost when the computer is turned off.

2. Long Lifespan: CMOS batteries are built to last, typically several years, before needing to be replaced. This means users usually don’t have to worry about frequent issues caused by CMOS memory loss.

3. Compact Size: CMOS batteries are small and compact, making them easy to fit into a computer’s motherboard.

4. Low Self-Discharge Rate: CMOS batteries usually have a low self-discharge rate, meaning they hold their charge well when not actively in use.

5. Cost-Effective: CMOS batteries are relatively inexpensive components, and replacing them is a simple and affordable solution when needed.

CMOS Battery Capacity

A typical CMOS battery has a capacity in the range of 200 to 500 milliampere-hours (mAh). The exact capacity can vary depending on the specific type and model of the battery used in a particular computer or motherboard.

The main function of the CMOS battery is to provide a small, steady power supply to maintain the CMOS memory. Because of this, smaller capacity CMOS battery cells are sufficient.

Note: When a CMOS battery is depleted or reaches the end of its service life, users might encounter problems such as incorrect date and time settings or BIOS/UEFI configuration errors. In these cases, replacing the CMOS battery is a straightforward fix.