How do I replace the BIOS battery in my laptop?
What Does the BIOS Battery Do?
The BIOS battery is designed as a source of power that provides power to the clock and BIOS or configuration memory (CMOS) for your laptop.
How to Replace the BIOS Battery in a Laptop
The exact procedure that you use to change the BIOS battery in a laptop will vary depending on the make and model of the laptop that you have. However, the strategy that you use should be quite similar to the directions provided here. Most laptops today use a Lithium (Li) battery that is held in a spring-like manner. However, some laptops use a Nickel-Cadmium (NiCd) battery.
Directions for Replacing the BIOS Battery in a Laptop
1) Before changing the BIOS battery in your laptop, you should write down all of your settings from the setup mode if the laptop that you have is very old. You do not need to do this with newer laptops.
2) Obtain a replacement battery before removing the BIOS battery. The battery must be exactly the same and is usually identified with a number. You can usually purchase the correct BIOS battery using the laptop's make and model.
3) You should close all open applications and turn off the laptop before switching bios batteries.
4) Disconnect all peripherals from the laptop including external speakers, USB mouse, power cables, printer, etc.
5) Carefully turn the laptop over and look for the area where the main laptop battery is secured. Open/unlock the release latches for the battery and carefully remove it.
6) Since the BIOS battery sits in the motherboard, you now need to turn the laptop over and remove the cover. If your laptop is still under warranty, you might want to see if this activity is going to void your warranty before you complete this task. The keyboard assembly is typically connected to the laptop with ribbons that you must be careful not to damage.
7) Remove the battery carefully. You might need a small screwdriver to help you pop the battery out. The Lithium battery is usually used with a socket that has a lateral tab, upper tab, or one in which the battery stands up. When you remove the battery, it is best to jot down how the current battery has been inserted in the laptop so that you can insert the new BIOS battery in the same manner.
8) Insert the new battery in place of the one that you just removed.
9) Reconnect the laptop's peripherals and power cables.
What if the BIOS Battery Is Soldered to the Motherboard?
If the BIOS battery is soldered to the motherboard, then you must replace the entire motherboard or have an experienced technician replace it for you. It is uncommon for this to be the case, but it does happen.