What Happens If You Start Computer Without CMOS Battery?

Published on: September 26, 2022
Written by Nolan Miles / Fact-checked by Porimol Sorkar

Have you ever wondered what would happen if you started your computer without the CMOS battery? Well, let’s find out. The CMOS battery is responsible for storing all of the settings on your motherboard.

If you remove it, all of those settings will be reset to their default values. That means that your CPU clock speed will be reset to its default value and your memory timings will be reset as well.

If you start your computer without the CMOS battery, it will default to the settings it had when it was last shut down. This can cause problems if the settings have changed since then. For example, if you’ve overclocked your CPU, starting without the CMOS battery may cause it to run at a lower speed.

How to Start PC Without CMOS Battery?

If your computer has a CMOS battery, you may be wondering how to start it without one. The good news is that it is possible to do so, but there are a few things you need to know first. The most important thing to remember is that starting your computer without a CMOS battery will result in the loss of any unsaved data.

This means that if you were in the middle of working on something, you will need to start from scratch. Before proceeding, be sure to save anything important that you don’t want to lose. Once you’re sure everything is saved, locate the jumper on your motherboard labeled “Clear CMOS.”

This will likely be near the CMOS battery itself. Using a metal object such as a screwdriver or paperclip, short the two pins labeled “Clear” for about five seconds. This will reset the BIOS and allow you to boot up your computer without a problem.

Keep in mind that this method should only be used as a last resort. If possible, it’s always best to replace your CMOS battery with a new one before taking this step.

Can a Laptop Start Without CMOS Battery?

If your laptop doesn’t have a CMOS battery, it’s still possible to start the computer. The CMOS battery provides power to the Complementary Metal-Oxide Semiconductor, which is responsible for storing information like the system time and date. Without a CMOS battery, this information will be lost when the computer is turned off.

In order to start your laptop without a CMOS battery, you’ll need to make sure that the RTC (real-time clock) is set correctly. This can be done by setting the date and time in the BIOS settings. Once this is done, you should be able to save your changes and reboot your laptop without any issues.

No CMOS Battery on Motherboard

If you’ve ever wondered why your computer’s CMOS battery is missing, you’re not alone. Many motherboard manufacturers don’t include a CMOS battery on their products. So why is this?

The answer is simple: cost. A CMOS battery adds an extra $5-$10 to the cost of the motherboard, and most consumers are willing to go without it. After all, the only thing a CMOS battery does is keep your system clock accurate and your BIOS settings saved – neither of which are essential for most users.

Of course, there are some downsides to not having a CMOS battery. If you live in an area with frequent power outages, or if you often have to unplug your computer for some reason, you’ll find that your system clock gets reset and your BIOS settings get erased quite frequently. This can be annoying, but it’s really not a big deal in the grand scheme of things.

So there you have it – the reason why many motherboards don’t come with a CMOS battery is simply because it’s not essential and it saves the manufacturer a few dollars.

Cmos Battery Low

If you’ve ever had your computer start acting strange, or even fail to start up altogether, it could be due to a low CMOS battery. The CMOS battery provides power to the computer’s BIOS chip, which stores information like system settings and boot order. When the battery starts to die, it can cause all sorts of problems.

In this article, we’ll talk about what the CMOS battery is, what it does, and how to tell if yours is on its way out. We’ll also show you how to replace it so that you can get your computer back up and running smoothly.

What Is the CMOS Battery?

The CMOS battery is a small coin-sized battery that provides power to the BIOS chip on your motherboard. This chip stores important information like your system settings and boot order. Without power from the battery, the BIOS would lose this information every time you powered off your computer.

How Do I Know If My CMOS Battery Is Low?

There are a few symptoms that can indicate that your CMOS battery is getting low: Your computer’s clock seems to be losing time or resetting itself frequently.

This is because the BIOS relies on power from the battery to keep track of time. You have trouble starting up your computer or it takes longer than usual to boot up. This can be caused by corrupted BIOS settings that are caused by a low CMOS battery.

You see error messages related to your BIOS or hardware when you start up your computer. These messages may say something like “CMOS checksum error” or “CMOS read error”. These errors can be caused by a loss of power to the BIOS chip due to a dying batteries.

CMOS Battery Lifespan

As technology advances, the lifespan of CMOS batteries also increases. In the early days of computing, a CMOS battery might only last a few years where wrist watch battery last less before needing to be replaced. Today, however, it’s not uncommon for CMOS batteries to last upwards of 10 years.

Of course, there are a number of factors that can affect the lifespan of a CMOS battery. The type of battery used, the quality of the battery, and how often it’s used are all important factors. However, in general, you can expect a decent CMOS battery to last for several years.

If you’re using a laptop or desktop computer that is more than a few years old, it’s likely that the CMOS battery needs to be replaced. If your computer is having trouble keeping time or if you see error messages related to the date and time, these are both good indications that it’s time for a new battery. Replacing the CMOS battery is generally pretty easy and only takes a few minutes.

Simply locate the old battery on your motherboard and remove it (be careful not to touch any other components!). Then insert the new battery into the same spot and secure it in place. Finally, restart your computer and check that everything is working properly.

If you find yourself replacing your CMOS batter more frequently than every few years, there may be something else going on with your computer system. It’s always best to consult with an experienced technician to diagnose any underlying issues.

Changing CMOS Battery in Desktop

If your computer is having issues starting up, or if you’re noticing strange behavior that you can’t quite pin down, it might be time to change your CMOS battery. The CMOS (complementary metal oxide semiconductor) battery gives power to the BIOS chip so that it can remember things like your system clock and boot order when the computer is turned off. Over time, the CMOS battery will slowly lose its charge and eventually need to be replaced.

You can usually tell when this is happening because the date and time on your computer will start resetting itself after being turned off for a while. If you suspect that your CMOS battery needs to be changed, follow these steps:

1. Shut down your computer and unplug all of the cables.

2. Find the location of the battery on your motherboard. This can vary depending on your motherboard model, but it’s usually near the CPU socket or along one of the edges of the board.

3. Gently remove the old battery from its socket and insert the new one in its place making sure that it’s facing the correct way.

4. Reattach all of the cables and turn on your computer. Check to see if the date and time are now staying set after being turned off for a while—if not, then you may need to enter this information into BIOS again (consult your motherboard manual for instructions on how to do this). That’s all there is to changing out a CMOS battery!

Dell CMOS Battery Failure Symptoms

If your Dell laptop is experiencing any of the following symptoms, it may be due to a CMOS battery failure:

1. Your computer won’t power on at all. This is perhaps the most obvious symptom of a failed CMOS battery.

2. Your computer powers on but doesn’t boot up properly. This can be caused by a variety of issues, but a failed CMOS battery is often to blame.

3. The date and time on your computer are wrong. This is another common symptom of a failing CMOS battery. If the battery can’t hold a charge, it can’t keep track of time properly either.

4. You see strange error messages or experience strange behavior when trying to use certain features or programs on your computer.

Once again, this can be caused by several different things, but a failing CMOS battery is often the root cause.

How to Charge a CMOS Battery?

If your computer has a CMOS battery, it’s important to know how to charge it. This type of battery is used to power the BIOS chip, which stores information about the computer’s hardware configuration. When the CMOS battery dies, the BIOS chip loses its data and the computer may not be able to start up.

To charge a CMOS battery, you’ll need to remove it from the motherboard and connect it to a power source. You can use a standard AA or AAA battery, or you can purchase a specialized CMOS charger. Once the battery is connected, allow it to charge for at least 24 hours before replacing it on the motherboard.

what happens if you start computer without cmos battery
Credit: www.hp.com

What Happens If You Run PC Without CMOS Battery?

If you run your PC without a CMOS battery, it will eventually lose all of its stored settings and revert to default. This includes the date and time, as well as any custom BIOS settings you may have changed. Without a CMOS battery, your PC will still function normally, but you’ll have to keep resetting these settings every time you power on your computer.

In short, it’s not worth the hassle to run your PC without a CMOS battery.

What Happens If My CMOS Battery Dies?

Your computer’s CMOS battery provides power to the CMOS chip, which stores information about your computer’s hardware configuration. If the battery dies, the information stored in the CMOS chip will be lost and your computer will not be able to boot up. You will need to replace the battery in order to use your computer again.

Can a Laptop Work Without CMOS Battery?

A laptop can work without a CMOS battery, but it will default to the most basic settings and will not remember any changes that are made. The CMOS battery provides power to the BIOS chip so that it can remember settings even when the laptop is turned off. Without a CMOS battery, the BIOS settings will be reset every time the laptop is turned off.


If you start your computer without a CMOS battery, it will not be able to remember any of the changes you make to your BIOS settings. This means that every time you boot up your computer, you’ll have to enter your BIOS settings manually. Additionally, if you have a website that you use regularly that requires cookies, those cookies will be erased each time you restart your computer without a CMOS battery.

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