Does using the laptop always connected to the mains damage the battery?


A laptop is a machine designed to be mobile, so it brings a battery included in the ‘package’. However, truth be told, it is quite normal to see laptops longer connected to the mains than running on battery power. Especially now that we have so many people working at home.

But isn’t this form of use bad for the laptop battery?

The explanation is not simple, so let’s go in parts.

While some years ago it was relatively simple to remove the battery from the notebook and use it only connected to the mains, the vast majority of modern notebooks come with integrated batteries that are very difficult to remove or replace.

Which begs the question… Is it always a good idea to always have your laptop plugged in?

Does using the laptop connected to the mains damage the battery?

First of all, it is necessary to bear in mind that there are two types of batteries:

  • lithium-ion
  • lithium-polymer

That said, despite being different technologies, they work in very similar ways. Where the statements below are true:


  • A battery is not always charging. (When it reaches 100%, it finishes charging. It recharges when the voltage drops, for example, 99%).
  • Losing the charge completely will damage the battery. That is, leaving the battery at 0%, and leaving it like this for a long time, can put the cell in a “deep discharge state“, a state that can be unrecoverable.

Having said all that, how does a Lithium battery lose capacity or get significantly damaged?

Therefore, the truth about this type of battery is that they are very unstable and start to lose capacity as soon as they leave the production lines. However, there are several factors that can accelerate this event.

  • A battery is no longer addictive, but all batteries have a finite number of charge cycles. The more cycles you have, the more worn it will become. (100 to 0% is a complete cycle, and 100 to 99% is 1% of a cycle).
  • Voltage level. The higher the battery charge level, the shorter the battery life. (It’s a slow wear)
  • Too high or too low temperatures can damage the cell. Which in turn decreases the battery capacity. (Leaving a laptop in a car in the sun can cause a significant rise in temperature, which in turn has harmful effects on the battery. Even if the laptop is off.)


  • A battery can be protected by trying to keep the charge percentage between 40% ~ 80%. (According to some studies, you may be able to achieve 3x or 4x more cycles)
  • Avoid fast charging, as they cause the cell to heat up.


In short, leaving the notebook always plugged in is not the best idea ever. Incidentally, some manufacturers even advise removing the battery if you intend to use the notebook only through the charger. Interestingly, Apple had this advice on its website for months:

  • “The ideal use of a MacBook is to use the laptop on the train, and then carry it around the office. This keeps the “juices” from the battery continuing to flow.”

But is it the end of the world to have the charger plugged in?

No, this type of use will not cause serious damage immediately. It is something that you will only notice in the medium/long term.


What’s the solution?

Here is the beauty of the situation… There is no ideal solution. If you always use the charger, it will cause damage. But if you always use the battery, you will spend the charge cycles more quickly.

Therefore, the ideal use is somewhere in the middle, that is, in a compromise between these two types of use.

Furthermore, what do you think about all this? Share your opinion with us in the comments below.