All personal computers, including desktops and laptops, since the 1990s, have the same CMOS model battery (i.e., CR2032) on their motherboards. Yet not all motherboard batteries are created equal, and their lifespans can vary greatly.
A new motherboard (or CMOS) battery will usually last an average of five years, depending on how often you use your computer. Some CMOS batteries cease after 1-2 years. Others can remain in working condition for up to 10 years if you use your PC regularly, which extends their lifespan.
There could be many reasons for a battery either lasting longer than expected or dying early. Some signs of ‘battery failure’ can point to other malfunctions (e.g., CMOS corruption). The important thing is to diagnose any issue properly before assuming that your motherboard battery is dead.
How Often Should You Replace Motherboard Battery?
The motherboard battery on your computer should last roughly five years, give or take. There is no definitive timeframe within which you should replace the battery. If your computer receives power from its motherboard battery, you can keep the existing battery intact. You only need to replace it once you start experiencing problems related to battery failure.
What Are The Signs Of CMOS Battery Failure?
Since there is no guarantee of a specific lifespan on a motherboard battery, it is important to notice any signs of battery failure. Here are some common problems that indicate your battery is dying:
- Your computer has difficulty starting up or shows a boot error or Run Setup on the screen
- The computer keeps shutting down without any user input
- The computer shows the wrong date and time, or a Clock Error or Clock Message appears on your screen
- You are not able to visit certain websites or access services due to the incorrect date and time
- There’s a constant beeping noise from the motherboard
- Some hardware drivers have disappeared or not working properly
- You can’t connect to the internet
- After you have pressed F1, an invalid drive specification appears on the screen
- Invalid configuration or Press F1 appears on the PC screen
- Peripherals, like the keyboard or mouse, aren’t responsive, or they don’t respond correctly
- Your computer’s BIOS passwords will reset
- Printers may not work and display a message “can’t find the printer.”
It is essential to consider that these signs might also mean something else, like the corruption of your computer’s CMOS, a relatively common occurrence. Problematic BIOS/UEFI might also present itself as battery failure. If unsure, take your PC to a computer technician or try the following methods to eliminate potential problems:
- Reset your BIOS to factory settings by removing the CMOS battery for approximately 5 minutes and then reconnecting it.
- Re-flashing the BIOS to get the latest version
- Reset your CMOS battery. This test involves opening your PC and removing the jumper for 20 seconds. If you do not feel comfortable opening the hardware yourself, send it to a professional.
If none of these steps resolves this issue, then you can rest assured that your motherboard battery has died and will need replacing. To confirm this, you can also use a multimeter to test your CMOS battery. Remove the CMOS battery, set the meter to DC voltage, and test the voltage. A healthy CMOS battery will read over 3.00 Volts.
What Happens When the CMOS Battery Dies
If your motherboard battery fails, you can still use it as a regular computer if you use the PC while plugged into an electrical socket.
Once your battery is finally dead, your battery would have removed all your computer’s boot settings, so your screen will turn blank in blue or black color. This sign means you have lost your CMOS (Complementary Metal-Oxide Semiconductor) memory. CMOS is the memory on a motherboard that stores the BIOS settings. The BIOS firmware will thus also shut down and revert to its default settings.
A CMOS battery is not rechargeable, nor can you fix it once dead, so you will have to replace it. To do this is a relatively simple task. To start:
- Power off your computer and unplug the power source cable.
- Take a small, flat-headed screwdriver and use it to remove the screws of the side casing to gain access to the motherboard and thus the CMOS battery.
- Once the case is off, remove the battery by using the screwdriver to push the metal tab back away from the battery gently. The battery should release without much force.
You will see that the CMOS battery most likely holds the model number CR2032, a standard lithium coin battery cell found in calculators, watches, and some medical devices and toys. It is therefore widely available, and you can purchase one and replace it with the old one. Make sure you buy a battery with the correct voltage (3V-6V) for your particular PC.
If you have installed the new battery and the problems persist, or you are not confident in replacing the battery yourself, you should consult a computer technician.
Can a PC Run Without CMOS Battery?
Your personal computer can run without a CMOS battery since the battery does not provide power to the entire computer. It only provides power to the CMOS when the computer is off.
Still, your computer will start with the default BIOS settings. Your PC will function, but everything in your BIOS like boot order, time and date, and other functions will reset, which means you will have to reset the clock every time you turn on your computer. You might also have to choose the drive where the OS installs every time you boot your computer.
Your computer has an average backup charging time, so you can still run your PC for 4-6 hours when your battery dies. Some newer and high-end computer models can provide up to 12 hours of backup charge.
A motherboard battery can last you anything from 1 year to 10 years. It is tough to predict how every battery will react since each person’s computer usage differs. One thing that has proven to extend the lifespan of a CMOS battery is using your PC often. When you go without using your computer for a long time, the battery drains from constant use preserving important startup information.
Various signs indicate that your motherboard battery is failing but be sure to diagnose the problem correctly. Conducting a few quick tests can help you to eliminate other potential issues. Once you have ascertained that your CMOS battery is dead, it will need replacing.
I started building and fixing PCs in high school. After a couple of years of offering consultancy to a PC repair shop, I became the goto guy for all my acquaintances for PC/Laptop related buying advice or troubleshooting.