How to Test if the CMOS Battery Is Bad

Learn to test your computer for a bad CMOS battery.

Your computer's CMOS (Complimentary Metal-Oxide Semiconductor) is a small, battery-powered chip built into the motherboard. It stores basic data instrumental to your computer's overall performance. It primarily stores your computer's internal clock settings, and allows some of your computer's hardware to communicate with the operating system. When the CMOS battery goes bad, it can cause some of your hardware to behave erratically. 

Bad CMOS Battery

While a CMOS battery generally lasts 10 years, it can fail at any time.

A complementary metal oxide semiconductor (CMOS) battery uses both negative and positive negative polarity circuits to operate. According to Webopedia, this means that the battery chip is smaller than standard chips, making them useful for small or portable devices. Laptops and personal computers use a CMOS battery for certain memory functions, including the date and time. If you computer is not working properly, you may not actually have a problem with the computer. Check these symptoms first to determine whether or not it's the CMOS battery