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Signs of CMOS Battery Failure of a Motherboard


A CMOS battery is a small battery that is installed on the motherboard of your computer. It has a life of about five years. You must use your computer regularly to extend the life of your CMOS battery.

The power supply of the computer increases the availability of the standby current and hence extends the battery life.

If the computer is not permanently connected the battery life is usually 3 years. However, the battery life is extended to 5 years when you use it regularly. The battery provides power to the CMOS memory and the clock in real-time.


CMOS Battery Failure Signs Or Symptoms In PC

This is a 3-volt battery. If the voltage drops between certain levels the computer loses memory. CMOS settings like date and time vary. In some cases, the date and time are set as the factory default. 

For example, your computer date will be set to factory settings something like 01/01/2002.

• All settings such as drive type, NUM lock, etc, in the computer setting will change. This can cause boot problems because your computer does not remember disk drive information.

• A message such as “Boot error unable to detect disk drive” will be displayed on your computer.

• The computer may shut down and not allow you to perform any task.

• Your computer may be too slow. This could be because of an incorrect time and date. It’s time to replace the failed CMOS battery for the solution.

• Some drivers may be missing or may not work properly. Therefore you may not be able to print to a printer. Even if you install the printer driver correctly your computer may continue to display the “Do not find a printer” message.

• Your mouse may not respond properly. You may feel your mouse is damaged and be ready to replace the mouse. But it can be solved by simply replacing the CMOS battery. 

Therefore before ordering a mouse you can try the same mouse on another computer to see if it is indeed defective. So you can save the money you earned hard!

• You may not be able to connect to the Internet. This continues to show an error when connecting to the Internet. You need to check if the time and date are correct. 

If the date and time are incorrect, try to correct them. Then check again If the computer still does not connect to the Internet you need to replace the CMOS battery.

• If you hear a constant beeping sound when working with your computer this is a sign or symptoms of a battery failure and that you need to replace the CMOS battery.

The computer will also display a CMOS battery failure, a CMOS read error or a CMOS test error, and so on. If this happens you must turn on the computer and leave it on for 24 hours. 

If the computer does not display the errors after rebooting the CMOS battery will charge. Otherwise, you need to replace the CMOS battery.


Where To Purchase The CMOS Battery For Your Computer

You can visit your local computer store to buy a CMOS battery for your computer or laptop or netbook. You can also buy the coin-shaped 3V CMOS battery from online stores. 

It is recommended to use the premium CMOS battery to power your computer without any problems. It will last more than 5 years. However, you can also buy a cheaper version of the 3V lithium battery for your computer. 

But it’s life is much less compared to the premium version. Therefore it is advisable to buy a premium version of the battery for your computer.

Before buying a battery it is advisable to check the CMOS battery rating on your computer and order it from an online store. 

Online stores usually deliver the items within 5 to 7 days. If you can not wait that long you can also buy the premium version from your local computer store.


CMOS Battery Failure Solution

Replacing a CMOS battery on your laptop or computer is easy. If you are new to a computer or laptop you can also enlist the help of a local computer technician to replace your computer battery.


Steps To Replace The CMOS Battery

First, turn off the computer or laptop and disconnect the power cord from the computer. It is also recommended to remove the battery pack from a laptop.

• Remove the processor or laptop cover using a Torx screwdriver.

• You can find a button-type CMOS battery on the motherboard of your computer or laptop. Use a flat-head screwdriver to slowly lift the button compartment off the motherboard.

• Use a multimeter to check the battery voltage (use a digital multimeter). If the voltage is below 3 volts your computer will not remember the CMOS settings so it’s time to replace the old battery with the new CMOS battery.

• After replacing the battery in the same direction you can replace the computer cover and tighten the screws.

• Plug in the power cord and turn on the computer to see if it is working properly. However, after replacing the failed CMOS battery you must enter the correct BIOS settings. Therefore after booting the computer you need to enter the correct date and time.