CMOS battery on the motherboard

Surely many users are well aware that a personal computer system contains an BIOS battery, but perhaps not everyone is aware of ​​what it is intended for. Some computers are unable to book without a functioning RTC CMOS battery; however, most modern computers will operate just fine with limited functionality. 

What is it for?

A real-time clock that is responsible for timekeeping while the computer is turned off will not function properly without a charged Battery for motherboard. This in turn can limit the functionality of computer programs and windows updates. 

Is it easy to replace?

Most computer manufacturers design their systems with easy access to the PC CMOS battery as they expect a user for a field technician to replace it at some point down the road. In some rare instances, the battery is hidden deep inside of the computer and a full tear-down is needed to replace it. Please check the location of the CMOS battery in motherboard before ordering the battery. This can be done by visiting the manufacturer’s website and looking for the repair manual for the exact model of the PC. 

Most computer repair shops can replace the CMOS battery for laptop; however, it is important to get a quote before authorizing a replacement. 

When to change

It is recommended to install a new battery when the following symptoms appear:

  • The battery is swollen or appears larger than usual.
  • Voltage drop – 2.7V or less is considered critical. Good batteries are in the 2.9V-3.2V range.
  • Changing date and time at boot.
  • Inability to turn on PC. The system does not boot or gets stuck on the BIOS screen.
  • Changing the BIOS settings. With a dead battery, the factory settings are constantly returned (older computers only).
  • Warnings about incorrect time/date appear when opening some applications.
  • Unreasonable obsolescence of anti-virus databases. Some antivirus programs won’t start at all without a correct system date and time.
  • BIOS-related error messages appear. 


Rome Tech Batteries manufactures only the best quality desktop and laptop CMOS batteries suitable for devices: