• noble okonkwo

Five signs of a failing CMOS battery



You probably noticed that your laptop has been acting weird, and you cannot seem to trace the problem. Well, if you have used the laptop for a while, there is a likelihood that its internal CMOS battery is dying.

While that may not necessarily be the case, it is a possibility, and the only way to confirm is to look out for some signs. To properly assess the situation, though, it is essential to understand how CMOS batteries work and their relevance to the system.

CMOS means “Complementary Metal Oxide Semiconductor,” and it functions as a primary power source for your laptops’ Basic Input/Output System (BIOS), which in turn helps the system access software when turned off.

The CMOS battery is an integral part of the computer system, as it powers certain fundamental features of your pc when your pc is disconnected from a traditional power source (ac).

If the CMOS battery is dying, it could potentially pose some risks. To avoid said risks and prevent complications, you should look out for signs like these;

It takes forever to boot

If you notice that your laptop takes an unusually more extended time than expected to start up, it probably implies that your battery is dying. Since the BIOS is responsible for starting up the computer, and the BIOS relies on the CMOS battery to function, booting becomes slower when the battery is dying.

Pre-installed drivers have suddenly gone missing

Another omen pointing to the gradual demise of your laptops’ integral battery is the sudden disappearance of drivers or software formerly installed in the system. You may even reinstall them, only to find them missing after rebooting the system.

You can't connect to the internet

If you find it harder than usual to connect to the internet with your computer, it probably means your computers’ internal battery is dying.

Date/Time reset

Your computer battery may be dying if you notice that the date and time on the system have auto-reset to a time most likely in the far past anytime you boot-up your pc.


This remains one of the most telling signs.

The keyboard seems to malfunction

If your keyboard, cursor, or other peripherals no longer seem to obey the correct commands or retrieve strange, incorrect data, your computers’ internal battery is most likely giving up the ghost.

While a number of other issues could cause these symptoms, it makes perfect sense to check your the health of your CMOS battery as the first line of action. This can save you a lot of money seeing that these batteries cost below 2,000 naira.


Most laptops with embedded secondary batteries (non-removable batteries) may not have a CMOS battery. However, this is dependent on the manufacturer.

11 views0 comments