Every motherboard has a small amount of memory on it to provide storage for the BIOS settings. This is known as the CMOS (Complementary Metal Oxide Semiconductor). The memory is powered by a CR2032 battery. This battery is to provide power to the CMOS when your computer is turned off. The CMOS controls the BIOS settings of your computer so date, time, and hardware configurations can be tracked while your computer is powered off.
The battery on older motherboards can fail as most CR2032 batteries only last around 2 to 5 years. Depending on the use of the computer. Regular use will allow the battery to last longer since it can recharge while the computer is turned on. If the computer has been sitting off for an extended period of time you can expect it to be drained. So if your computer has been off for a while try leaving it on for 24 hours to allow the battery to charge. if this doesn’t solve the issue we can continue on to see with the tutorial.
How to Detect CMOS Battery Failure
Here is list of the most common errors that you will notice when your CMOS battery starts to fail. Some batteries might sill emit a small charge to generate some power like 1.6 volts even thou it should be generating 3V. This will also cause some errors and might be a little harder to detect. If you notice any of the following then it is time to replace your battery.
- The most common error that you will find is that your computer will no longer show the correct date and time. Every time your computer is turned on it will display a default time and date. 12:00 AM 1/1/00 or something along those lines.
- Error messages such as “CMOS checksum error” or “CMOS read error”. Maybe display when booting up.
- A beeping noise can be heard coming from your motherboard.
- Peripherals that use drivers such as a mouse will start to not work or act funny. Due to the battery not saving the settings.
- The computer may turn off for no reason.
- Having trouble connecting to the internet because your system is showing the wrong date and time.
How to Replace a CMOS Battery
Replacing the battery is a pretty simple task that anyone can do. Just make sure before working on your computer that everything is unplugged so there isn’t any power going to your computer. You will also need a replacement CR 2032 battery. These can be purchased from any hardware store or from Amazon.
- Open up the case of your laptop or desktop. So you have access to the motherboard. (Make sure your computer is powered off and unplugged before proceeding with opening your computer case. If using a laptop remove the battery pack.)
- Find the battery. The location of the battery is different for each motherboard. But it is pretty easy to spot as it will be a CR 2032 battery which is a circler.
- There is a leaver on the side of the battery, you can use a screwdriver to help pop it out. or you can simply grab the battery with your thumb and index finger to remove it.
- Using the new battery. Push back into the socket you just removed the old one from. It should click back in and be securely placed.