What is the backup battery? The CMOS (Complementary Metal Oxide Semiconductor) battery powers the CMOS chip when the PC shuts down. This chip contains BIOS information and settings. So, to reset the BIOS settings, we can remove the CMOS battery. Replacing the CMOS battery is quite simple. However, spotting it can be quite difficult, especially for beginners. In this article, we will show you how to find it and how to replace the backup battery. But first, let’s see why we need to change the CMOS battery.
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PC buffer battery what is it for?
Removing the CMOS battery will reset all BIOS settings to their default values. So, if we have a PC that won’t boot due to an error in the BIOS setting, we can try to replace the CMOS battery to fix the problem. Another reason we need to remove the CMOS battery is that it is dead. The computer’s BIOS will continue to reset itself every time the computer is turned off when the CMOS battery is low.
CMOS battery type
Depending on the type of motherboard, there are two ways a CMOS battery is connected to it. For motherboards with ATX size, the CMOS battery is connected directly to the motherboard without cables. However, on mini-ITX motherboards, the CMOS is wrapped in colored insulating plastic connected to a header on the motherboard with a red and black cable.
How to change the backup battery on the PC?
Removing the battery from the motherboard is quite simple as it is enough to press with a small metal lever that brings it out. However, novice PC builders may have trouble locating the CMOS battery as its location on the motherboard varies by manufacturer.
We have mentioned the following steps to make the backup battery removal process easier. Please follow them one after the other. Before you start, follow these steps to download the motherboard.
- Turn off the system and remove the cable from the wall outlet that connects to the computer.
- Press the power button four to five times to discharge all capacitors on the motherboard.
Now, follow these processes to take out the battery.
Remove the side panel
First, we need to access the motherboard by removing the side panel. Please follow these steps to remove the side panel.
- Remove all screws on the back or side. Most motherboards have a removable side panel on the left side of the CPU case.
- Gently pull the panel out of the CPU case.
- Now you can also see the graphics card, processor, RAM, and power supply (power supply).
How to find the CMOS battery
The physical structure of the CMOS battery is like that of a clock, flat and cylindrical, just like a coin. To locate it, scan the motherboard and find a component that looks like a silver coin, to be precise.
For ATX cards
For medium to large motherboards, check around the PCIe Express or DIMM slots (RAM slots), as these chips are generally found around these areas. There is only one flat circular component on the motherboard, so it’s hard to miss. Once located, check the mark on the top of the battery. It should have a + sign. We should remember, inserting the battery incorrectly will not work. Therefore, the BIOS will continue to reset itself every time the computer is turned off.
For Mini-ITX
For smaller motherboards like the mini-ITX, check the board for a colored insulating plastic wrap. This plastic wraps around the CMOS battery. This colored plastic can be black, yellow, red, blue, or any insulating plastic. If you are having trouble locating the battery, you can always refer to your motherboard user manual.
How to remove the CMOS battery
Depending on the size of your motherboard, follow the steps accordingly.
For ATX motherboard
For larger motherboards that have a separate slot for the battery, follow these steps to remove it.
- Remove the battery by pressing the lock on the CMOS battery slot on the motherboard.
- The battery will pop out easily when pushed to the side.
If you have trouble using the lock, using a small, thin pin to remove the backup battery is also a viable option. However, make sure this pin is not conductive, such as a toothpick.
For Mini-ATX or M-ITX,
On a smaller motherboard, a wire is connected to the battery. Simply unplug the cable that connects the battery to the motherboard. However, before unplugging this cable, check its header to see how it connects to the motherboard. This is done so that you can easily reinsert the battery into the motherboard.
