A CMOS battery is a backup power source for storing BIOS settings. It can be used as a normal or rechargeable battery and should have a long enough lifespan. If the CMOS battery dies, it may not be possible to start your computer because the BIOS will not store any changes you make to your hardware configuration. You can check if your CMOS battery is dead by using a multimeter set on DC volts and measuring its voltage with all connections disconnected from the motherboard (including CPU, RAM, power cable).
If the CMOS battery dies, settings will be lost when the computer is powered down. You will probably be asked to reset the time and date when you start the computer up. Sometimes the loss of settings will prevent the computer loading the operating system.
That depends on the computer. For desktop computers, the answer is usually yes – a dead CMOS battery will prevent the computer from starting up. Laptops are a bit more complicated, since they have two batteries: one that powers the laptop itself, and one that powers the CMOS. If the CMOS battery is dead, the laptop may still start up – but it’s not guaranteed.
you can either replace the battery yourself, or take your computer to a technician who can do it for you. The process isn’t too difficult, but it can be a bit tricky if you’ve never done it before. So if you’re not sure whether you can do it yourself, it’s probably best to take it to a professional.
Here’s a quick guide on how to replace a CMOS battery:
1. Shut down your computer and unplug it from the power outlet.
2. Remove the cover of your computer case. This will vary depending on your computer model, so check your user manual for instructions.
3. Locate the CMOS battery – it should be a small, silver-colored battery with two metal contacts.
4. Use a screwdriver to remove the screws that hold the CMOS battery in place, and pull it out.
5. Take your replacement CMOS battery, line up the metal contacts with the ones in your computer’s motherboard, and push it into place. Make sure it is firmly seated in place before you screw it back down (being careful not to short them together). You can then reassemble your case and plug everything in again to see if that did the trick!
Does CMOS battery recharge?
Most CMOS batteries are CR2032 lithium button cell batteries and are not rechargeable. There are rechargeable batteries (e.g. ML2032 – rechargeable) that are the same size, but they can’t be charged by your computer. Some motherboards used to have rechargable CMOS batteries on them.
CMOS battery dying
A constant beeping sound is another sign that your CMOS battery is dying. The final sign that your CMOS battery is going dead is that you’ll receive an error message. The three main types of error messages are: CMOS Checksum Error, CMOS Read Error and CMOS Battery Failure.
A bad battery does not affect the performance of the laptop. What it DOES do, however, is shorten the lifespan of the laptop (and its hardware). If you are ONLY running on battery power, and are using a battery
CMOS battery cause shutdown
CMOS battery will not cause a shutdown. But a LEAKING CMOS battery can cause damage to the mainboard. If you see areas where the copper in the board is dark, or the board is discolored, it’s very possible that the battery fluids have corroded the motherboard.
If you find that there’s no voltage coming out of the CMOS battery, this means that it needs replacing before powering on again!