Can I Leave My Laptop Plugged in Overnight?

This is about whether you can leave your laptop plugged in overnight or even longer.

When plugged in, the computer gets power from the plug, not from the battery.

It won’t overcharge or drain the battery.

Here’s what you need to know!

Table of Contents

Power Source

When leaving your laptop plugged in, one thing to keep in mind is where the laptop is drawing its power:

All laptops come with an adapter or charger. The primary purpose of an adapter is to convert AC to a single DC voltage. 

In the video linked below, you will find a thorough explanation of AC and DC current differences.

  • DC= Direct Current

          Electrons flow in one direction

  • AC= Alternating Current

          The flow of electrons change

It’s a common question that people ask whether some laptops draw their power from the power adapter or their battery while plugged in. And the answer is, when plugged in, the computer uses power directly from where it is connected, and not from the battery. 

Laptop charging on a desk, connected to an outlet.

So, can I leave my laptop plugged in overnight or even longer?

Even if you left your laptop plugged in overnight, or even longer, it will not overcharge or draw power from its battery.

You can tell by looking at the power source on your screen. It will either say Power Adapter or Battery. 

Batteries

Most laptops today use lithium-ion batteries. They are the fastest growing and most promising battery chemistry, and for a good reason. 

They are low maintenance because no periodic discharge is needed. There is no memory, unlike nickel-metal-hydride batteries mainly used in the early ’90s calibrated to have a memory of the battery capacity.

Lithium-ion batteries are quite smart because once you fully charge it, it knows that it’s fully charged, and it automatically discharges ions.

In other words, it won’t accept any charge anymore. Knowing this eliminates any concern with overcharging a laptop battery.

According to The Battery University study, lithium-ion batteries have a protection circuit that limits each cell’s peak voltage during charge.

The protection circuit prevents the cell voltage from dropping too low on discharge, preventing temperature extremes and eliminating the possibility of metallic lithium plating possibly due to overcharge.

Maybe you’ve thought, I left my laptop charging for a week while away on vacation.

But with this study, we can conclude that leaving a laptop on 24/7 plugged in the wall will not overcharge, overheat, or damage a lithium-ion based laptop and that it is relatively safe to do so.

Battery Life

Lithium or not, battery life goes down with any tech device. When you get it on day one, you’re going to have 100% battery capacity, and by about six months later, you’re probably at 95% and so on. Depending on how you use it, it’s going to change how fast the battery wears. 

But generally speaking, every person who uses a tech device will notice a decrease in battery life over their course of ownership. 

Because lithium-ion batteries have a set number of discharges that they can go through, after this x number of discharges, it cannot hold any more charge, which is why you would have to replace your battery in the first place. 

Can I remove the battery and use my laptop powered only by using the charger? Is it better to use a laptop without a battery, some of you may ask? 

View of the side of a laptop charging on a wooden table.

Yes, you can! Some discharge may occur over time, and generally, a battery loses about 10 – 15% of its potency over a four-month period. 

Here are a few guidelines you must follow if you want to remove it:

  • Do not leave the battery unconnected from a power source for too long
  • It’s important to maintain a storage temperature of 32F to 95F
  • Charge it before storing

Ways To Preserve It

Under normal use, batteries have a life expectancy of 18-24 months. However, in cases where a laptop is used extensively, a reduction in battery efficiency can occur before this time. 

According to research, the best way to extend battery health is to maintain it at about 60% or anywhere between 40-80%. 

You can go into your system settings and let it know that it should not charge it above 80%. 

Suppose you are really concerned about overcharging the laptop battery & your battery health overall and don’t want to use the system setting. 

In that case, you can simply charge it up to 80% and then keep it unplugged until it drops to about 40-50% and then plug it back in and charge it back to 80%. It’s much better than charging it to 100% and letting it drop to 0. 

If this method doesn’t sound like something you would do, maybe because you spent hours working on your computer and prefer to leave it plugged in forever. 

You could go into battery charge configurations and type it manually at what percentage you want your battery to start and stop charging and not worry about its health. 

If you are an Apple customer, then see here for battery health mode

Plugged In

So here’s the big question. If I leave my charger plugged in, will it affect the charging capacity or shorten the overall battery life? 

The answer is no on both counts. As we mentioned above, what helps the battery is that it actually has integrated controls that stop the charging once the battery is fully charged. 

So leaving the charger plugged in overnight or even longer will not affect the battery’s performance.

What if I left my laptop charger plugged in the wall? Is leaving a laptop plugged in a fire hazard?  

Plug-in adapter power cord charger with laptop.

No, as long as the manufacturer approves the charger, it is not a fire hazard. But to minimize any risk, it is recommended to set the charger on glass, metal, or solid wood surface. However, a general rule is not to leave it plugged in if you don’t need to.

How To Extend Battery Run Time

Is it necessary to fully discharge your battery before recharging it? No, it is not. With the current ion batteries, this practice has absolutely no effect on battery run time. 

So once again, leaving your laptop on 24/7 or its charger plugged in overnight will not affect battery run time in the long run either.

One way to extend battery run time is to use your laptop’s power-saving controls to reduce battery usage on regular days. 

Reducing your screen’s brightness helps, as well as closing certain apps to save battery power and disabling certain features on your notebook whenever possible such as Bluetooth, wifi, or any external devices. 

Avoid exposure to extreme temperatures; if this does happen, wait for the battery to return to normal temperature before charging again. You can also run a diagnostic test on the battery to make sure everything is running smoothly.

A Note For Mac Users

If you own a MacBook, you can check the battery status menu under the battery icon.

The battery status menu will show how much charge the battery has as well as if there are any apps using a significant amount of energy. 

Under this icon, you will find battery preferences and choose to set up your notebook on battery health mode.

You can also use Apple Diagnostics to determine whether there are any issues with the battery overall.

First, you need to determine whether you are using a Mac with Apple Silicon or an Intel Processor. Prepare your Mac, then follow this guideline.

Should I Turn My Laptop off

Most of us find ourselves pondering the same question. Is leaving a laptop on overnight and never turning it off okay? And is it okay to charge a laptop while it is off?

The answer is simple. The battery will charge even when your laptop is off. Most laptops today have hibernation and sleep mode

Both these options allow you to leave your computer on and save your work while reducing energy.

You can access them from the Power settings both on Windows and Mac.  

Sleep mode conserves less energy than hibernation mode and allows your laptop to start up about immediately.

It puts all apps or programs that are open on your device into Ram, or random-access memory that is responsible for current activities on the PC or laptop.

When a process is in RAM, it means you can access it right away, and it won’t need time to load.

At the same time, your device goes to power-saving mode, and it pauses all activity. 

To exit sleep mode, simply press a key or click your mouse, and your computer will come back on.  

Hibernation is a deeper sleep mode compared to sleep mode because it doesn’t use any energy.

Similar to when you shut it down but takes more time to get over. In this state, your computer copies everything you have opened to the hard-drive instead.