Can Laptop Boot Without CMOS Battery (Comprehensive Guideline)

Published on: May 14, 2024
Written by Ian Carter / Fact-checked by Baten Khalil

One of the most common questions we get asked is whether a laptop can boot without a CMOS battery. The answer is yes, it can! In fact, there are a few different ways to do this.

can laptop boot without cmos battery

The first and most common method is to simply remove the battery from the motherboard. This will cause the system to lose all power and reset itself. You can also use a jumper on the motherboard to clear the CMOS settings.

If your laptop is having trouble booting up, it could be due to a dead CMOS battery. This battery is responsible for keeping the date and time settings in your BIOS, so without it, your computer won’t know what time it is. You can usually tell if the CMOS battery is dead if you see an error message saying “CMOS Battery Low” or something similar.

If your CMOS battery is indeed dead, don’t worry – you can still use your laptop without it. You’ll just need to set the date and time manually every time you turn on your computer. To do this, simply enter the BIOS menu (usually by pressing F2 or Del during startup) and navigate to the Date & Time section.

From there, you can set the current date and time. Once that’s done, save your changes and exit the BIOS menu – your laptop should now boot up without any issues.

Keep reading the article to find out more about CMOS batteries and how to boot different devices without a CMOS Battery.

How to Boot PC Without CMOS Battery?

Booting your PC without a CMOS battery is possible, but it’s not recommended. Doing so can lead to data loss and instability. The CMOS battery is responsible for keeping your computer’s clock accurate.

It also stores other settings like BIOS passwords, boot orders, and hardware configurations. Without the battery, your computer will be unable to keep track of time or remember any custom settings you’ve made.

If you absolutely must boot without a CMOS battery, there are a few things you can do to minimize the risk of problems:

Use a UPSUse a UPS (uninterruptible power supply) to prevent sudden power outages from disrupting your computer. Avoid making any changes to your BIOS settings. If possible, use default hardware settings instead of custom ones.
Have a backupKeep important files backed up in case of data loss. Booting without a CMOS battery isn’t ideal, but it can be done if necessary. Just be sure to take precautions to avoid potential problems down the road.
Things you can do to minimize the risk of problems

No CMOS Battery on Motherboard

no cmos battery on motherboard

If you’ve ever wondered why your computer’s CMOS battery is missing, you’re not alone. It’s a common question, and the answer is actually pretty simple. The short version is that most modern motherboards don’t have a CMOS battery.

The longer version goes like this: CMOS batteries are used to power the motherboard’s real-time clock (RTC). This clock keeps track of time even when the computer is turned off, which is why you can set your computer to turn on at a specific time. The RTC also controls things like your computer’s boot sequence.

In recent years, many motherboard manufacturers have started integrating the RTC into the chipset itself. This means that the RTC no longer needs its own power source, and as a result, there is no need for a CMOS battery. So if you’re wondering why your motherboard doesn’t have a CMOS battery, now you know!

How to Reset Bios on Laptop Without CMOS Battery?

If you need to reset your BIOS without a CMOS battery, there are a few different methods you can try.:

  • You can try removing and re-inserting the CMOS battery. This will usually reset the BIOS to its default settings.
  • If that doesn’t work, you can try shorting out the two pins on the motherboard that connects to the CMOS battery. This will also reset the BIOS. Finally, if all else fails, you can always just replace the CMOS battery with a new one.

HP Laptop Without CMOS Battery

If your CMOS battery dies, you’ll need to replace it. Here’s how to do that on an HP laptop.

First stepLocate the CMOS battery on your HP laptop. It’s usually located near the BIOS chip, which is a small, rectangular chip near the center of the motherboard. Once you’ve found the battery, unplug it from its socket.
Second stepGet a new CR2032 coin cell battery and insert it into the socket where the old one was. Make sure that the positive (+) side of the new battery is facing up before you plug it in. Once you’ve inserted the new battery, reassemble your laptop and power it on.
Third stepIf all goes well, you should see the POST screen (the first screen that appears when you boot up your computer). If not, try resetting your BIOS settings by pressing F2 during startup; this will load default settings and may fix any issues caused by a dead CMOS battery.
Step-by-step guidelines on how to replace hp battery

What Happens If CMOS Battery is Low?

If the CMOS battery is low, it may cause problems with your computer’s settings.

Malfunction in Information Store

The battery provides power to the CMOS chip, which stores information about your computer’s configuration. If the battery is low, the CMOS chip may not be able to store or retrieve the information correctly.

Frequent Error Experience

This can lead to errors in your computer’s settings. The symptoms of a low CMOS battery can vary depending on your computer system. You may experience errors when trying to save settings or changes may not be saved properly.

Error in Regular Activity

Your computer clock may also lose time or reset itself unexpectedly. In some cases, a low CMOS battery can cause your computer to display an error message on startup. If you suspect that your CMOS battery is low, you should replace it with a new one as soon as possible.


A dead or dying battery will eventually prevent your computer from starting up properly so it’s important to take care of it before that happens. Replacing the CMOS battery is usually a simple task that you can do yourself if you have basic technical skills.

CMOS Battery Laptop

A laptop’s CMOS battery is responsible for providing power to the computer’s BIOS chip so that it can retain all of its settings. This battery is typically a coin-sized CR2032 lithium battery, and it’s located on the motherboard. When this battery starts to die, you may notice that your computer’s clock starts to lose time or that your BIOS settings reset themselves after each reboot.

How to Replace a CMOS Battery?

how to replace a cmos battery

Replacing the CMOS battery is a relatively simple process, and it’s one that you can do yourself if you’re feeling handy. If your laptop is starting to act up and you suspect that the CMOS battery might be the culprit, there are a few things you can check before breaking out the screwdriver.

Here is a step by step guideline to do it:

First stepTake a look at the date and time in your computer’s BIOS. If they’re wrong or if they keep resetting themselves, that’s a pretty good indication that your CMOS battery needs replacing
Second stepAnother thing to try is booting up your computer in Safe Mode; if it boots successfully but then resets itself as soon as you exit Safe Mode, again, this points to a bad CMOS battery.
Three stepOnce you’ve confirmed that it’s time for a new CMOS battery, shut down your computer and unplug all of its cables.
Fourth stepFlip it over and remove any screws holding down the back panel; on some laptops, these will be hidden under rubber feet or stickers. With the back panel removed, locate the coin-shaped CMOS battery on the motherboard—it will likely have “CMOS” printed nearby (see image below).
Fifth stepGently pry out the old battery with a flathead screwdriver and pop in the new one; make sure it goes in snugly so that there’s no risk of it coming loose later on.
Final stepReplace any screws and reattach any panels or covers before powering on your laptop; once everything is back in place, boot up as normal and set the correct date and time in your BIOS (if necessary).
Step-by-step guidelines to replace CMOS Battery

With just a few minutes of work, you can easily replace a dying CMOS batter—and hopefully, extend your laptop’s life by months or even years!

CMOS Battery Failure

A CMOS battery failure can occur for a number of reasons:

  • The most common reason is a manufacturing defect in the battery.
  • Other causes include exposure to extreme temperatures, physical damage, or electrolyte leakage.

When a CMOS battery fails, it can cause a number of problems:

  • The most common problem is that the computer will lose its ability to keep track of time and data. This can be problematic if you rely on your computer to keep track of important events or deadlines.
  • A failed CMOS battery can cause your computer to forget certain settings, such as passwords or BIOS settings.
  • In some cases, a failed CMOS battery may even prevent your computer from booting up altogether. If you suspect that your CMOS battery has failed, there are a few things you can do to test it.

How to Test It?

  • One simple test is to unplug the power cord from your computer and then plug it back in again after waiting for about 30 seconds. If your computer boots up without any issues, then the battery is likely still working properly.
  • If you experience any problems booting up or keeping track of time and date, then it’s likely that the CMOS battery has failed and needs to be replaced.

Frequently Asked Question

Does a Laptop Battery Affect Performance?

If you’ve ever wondered whether the battery in your laptop affects performance, you’re not alone. Many people believe that a laptop with a bad battery will run slower than one with a good battery. There is no evidence to support this claim.

In fact, the only thing that a laptop’s battery life can affect is how long the device can be used without being plugged in. So, if your laptop’s battery isn’t holding a charge like it used to, it won’t impact performance.

What are the Steps to Check CMOS Battery Status Using Command Prompt?

To check CMOS battery status using the command prompt, follow this command prompt guide for checking cmos battery status: Open the command prompt by typing cmd in the Windows search bar, then enter wmic bios get and press Enter. Locate the SMBIOSBIOS Version line, which displays information about the battery. If the SMBIOSBIOS Version line shows OK, the CMOS battery is functioning correctly.

Is It Okay to Run Laptop Without CMOS Battery?

Laptops are designed to be run on a battery, so it is perfectly safe to run your laptop without the CMOS battery. In fact, it is actually recommended that you do this whenever possible to prolong the life of your battery. The only time you should not run your laptop without the CMOS battery is if you plan on making changes to the BIOS settings.

Otherwise, there is no need to worry about running your laptop without the CMOS battery.

What Happens If You Boot Without CMOS Battery?

Without a CMOS battery, your computer won’t be able to remember basic settings like the time and date. This can be annoying, but it’s not usually a big deal. You can still use your computer without a CMOS battery, but you’ll have to set the time and date every time you turn on your computer.

In some cases, you may also need to reset other BIOS settings if they get reset when the power is turned off.

Can Laptops Run Without a CMOS Battery


Laptops are able to boot without a CMOS battery, but the time and date will need to be reset every time the laptop is turned off. The CMOS battery provides power to the RTC (Real Time Clock) chip, which keeps track of time and date. Without this battery, the laptop will not be able to keep track of time or date.

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