Is It Bad to Leave Your Laptop Plugged in All the Time?

Evan Gower June 11, 2022

Leaving a laptop plugged in after it’s charged isn’t ideal, even with modern laptops using lithium-ion or lithium-polymer batteries which do not overcharge. Once your battery is full, the power will no longer run through the battery, but it will continue to draw power, heat up the laptop, and potentially cause problems.

Is It Bad to Leave Your Laptop Plugged in All the Time?

Once a battery is fully charged on a laptop, the extra electrons, i.e. the power that charges the battery has to go somewhere, which in most cases is the charging dock, the place where you plug the charger into the laptop, This article will cover what you need to know regarding your laptop battery life and give you useful tips to prolong it.

What Happens When Your Laptop Is Plugged in 24/7

Some old laptop models may have battery overcharge issues if you leave them on all the time, especially the nickel-cadmium-based batteries, but it is not necessarily the case with newer models. However, there is another problem with constant charging. It generates a lot of heat, which can severely damage your battery and shorten its life.

Here is a chart from Battery University, a great place to learn about batteries. It shows the negative impact of high temperatures on lithium batteries.

bad to leave my laptop plugged in all the time — *Image source: batteryuniversity.com*

Battery life slowly diminishes even at low temperatures, but if you leave your laptop plugged in constantly, you will reduce it even more quickly. You should invest in a good cooler for your laptop and avoid charging it after it is full for too long. The reason for this is not excess power, but excess temperature.

In short, the flow of electrons, electricity, produces heat, and this heat builds up more quickly when the laptop’s battery is full and the electrons have nowhere to go because the battery can’t store anymore, which can damage components. Aside from extra heat, keeping your battery at 100% all the time and plugged in will cause the gauge to not show accurate readings. For example, it can show that you have three hours left when in reality, you might have less than an hour.

While it’s true that laptops built in the last 10-15 years have circuitry built-in to prevent the issues of overcharging and heating, don’t rely on that entirely. Wasted electricity or the rare chance of a defective battery/circuitry just makes it worthwhile to treat your expensive laptop with care.

How to Fix These Issues

Do not worry; there is a fix for everything. If you notice your battery gauge is not working properly, you can recalibrate it. You need to change your power settings. Some laptops have a built-in battery calibration tool while on other laptops you will have to do it manually. You should do it once or twice a year.

In case you have a simple laptop and you do not use it for difficult tasks, it should be easy to keep it cool even at 100% battery. The battery will actually last longer than in a high-end model. The problem with high-end laptops is they are usually used for graphical rendering, whether in games or professional editing programs which can generate some serious heat. For such builds, it might be better to keep the battery at 40% rather than fully charged.

It is hard to guess your laptop’s temperature by just touching it. You can download a free program that will show you the current temperature of your processor. There are many available options. For example, Core Temp is a solid choice.

Additional Tips for a Longer Battery Life

Except for the temperature which plays a vital role in your Laptop’s battery life, voltage is also a huge factor. Your battery’s performance will weaken over time, no matter what you do. However, there are steps you can take to significantly slow the deterioration process down.

Each battery has a set number of charge cycles, depending on the voltage per battery cell. This is not easy to grasp, so here is another chart made by Battery University to make things clearer.

Is it bad to leave laptop plugged in all the time — *Image source: batteryuniversity.com*

At 100% charge, you get 4.20 V/cell in your battery, which gives you up to 500 discharge cycles. You can extend the battery life by decreasing the voltage a little. Newer laptops usually have programs to assist you with maintaining battery life. They will prevent your battery from staying at 100% constantly. Dell and Lenovo offer these features in their new models.

However, you can manage your battery life yourself by keeping it somewhere in the middle, not fully charged or completely drained. Anything between 30% and 80% is good, as long as the temperature is low as well.

Keep it Cool

Laptops are somewhat like people, they can’t handle too much stress and heat. It is important to have strong fans and take good care of your laptop’s temperature. If you notice it is overheating, you can take out the battery and charge it directly from the power source.

Voltage is also important, so try not to overcharge your battery. Not because of some old myths, but because it can reduce the number of your battery’s discharge cycles.