Should you keep your laptop plugged in all the time?

Xiaobai Software  2022-06-13 16: 44  read 114 views

At some point, all laptop owners find themselves thinking the same question: Is it bad to keep your laptop plugged in all the time?

As it turns out, the answer isn't entirely straightforward.So let's take a look.


Know Your Laptop Battery

There are two main types of batteries used in laptops: Lithium-Ion and Lithium-polymer.Although they are different technologies, they function in much the same way, both generating energy through the movement of electrons.This constant flow also helps keep the battery healthy.

For both types of batteries, the following statements are true (at least as far as modern laptops are concerned):

The battery can't be overcharged: If you're plugged in all the time, there's no danger of overcharging, even 24/7.Once it reaches 100%, it stops charging and doesn't restart until the voltage drops below a certain level.

Fully discharging the battery will damage it: Allowing the battery to fully drain for a long time may cause it to enter a deep state of discharge.This can be fatal - you may never be able to charge it again.

So, based on this, can we conclude that you should keep your laptop plugged in all the time?Not really.

Things That Hurt Lithium Batteries

The truth about lithium batteries is that they are inherently unstable.They become incapacitated from the moment of production, and many factors have accelerated their decline.These include:

Charge/Discharge Cycles: Each battery has a limited number of charges and discharges.

Voltage Rating: The higher the charge level (measured in volts per battery), the shorter the battery life.

High temperature: over 30 degrees Celsius.This may cause irreparable damage.

The last two are the ones we care most about. A comprehensive study from Battery University highlights how voltage levels and high temperatures can shorten battery life in isolation, as well as when they are combined.

charge or voltage level

Li-ion batteries are charged to 4.20 volts per cell, equivalent to 100% of their capacity.At this level, the battery will have a lifespan of 300-500 discharge cycles.


For every 0.10V/cell decrease in charge, the number of discharge cycles doubles until the optimum level is reached: 3.90V/cell with 2400-4000 discharge cycles.Unfortunately, at this level, the battery is only about 60% charged.The runtime will be a little more than half that of a fully charged battery.


Then there's the high temperature, which is usually classified as over 30 degrees Celsius, which, regardless of other factors, shortens the life of the battery.Leaving a laptop in the car on a summer afternoon is a bad idea.

When you combine high temperature stress with high voltage stress, the effect is even greater. Research from Battery University shows that at 40 degrees, a battery that stores 40% of its charge will drop to 85% capacity after a year.


Charged to 100%, the capacity dropped to 65% under the same conditions.For a battery fully charged at 60 degrees, the capacity plummeted to 60 percent in just three months.

The evidence seems clear.Leaving a battery at 100% charge for long periods of time will slowly shorten its lifespan.Keeping it 100% charged and exposing it to heat will shorten its life faster.

Remember, these high temperatures aren't just an environmental factor.Resource-intensive tasks, like gaming or video editing, will greatly increase heat levels, and placing a laptop on a pillow or in a poorly designed chassis can also trap heat.

Should you remove the battery?

If heat is so dangerous, that begs another question.Should the battery be completely removed when using the laptop on AC power?Obviously, this is not possible on the increasing number of laptops with sealed batteries.

Where they can be replaced, the answer seems to vary by manufacturer.For example, Acer says you don't have to remove the battery from AC power, but you should remove it if you won't be using it for a few days.When Apple makes laptops with removable batteries, it recommends never taking them out.


It all comes down to the laptop's power management settings.Some people may reduce power when they don't have a battery, just like some people do when battery levels get low.This may make your performance unsatisfactory.

If you do choose to remove the battery, make sure you store it properly.This usually means charging between 40% and 80% and keeping it at room temperature.

Should you keep your laptop plugged in all the time?

Will leaving your laptop plugged in ruin the battery?Yes, it will.But so does charging it every day.

Oddly, there doesn't seem to be a single answer across the industry to the question of AC or battery power.

We've seen that Acer recommends removing the battery when you're not using it.Asus says you should drain the battery by at least 50% every two weeks.But Dell says there's no problem with leaving the laptop plugged in all the time.


Apple's advice no longer appears on its website, but you can still read it online.The company advises against leaving the laptop plugged in all the time.Instead, it recommends:

"An ideal user is an office worker who uses her laptop on the train and then plugs it in to charge at the office. This keeps the battery alive..."

Is it bad to keep your laptop plugged in all the time?

There's no short-term damage to the laptop by plugging it in, but if you're only using AC power, you'll almost certainly see a significant reduction in the battery's capacity after a year.Likewise, if you're only using battery power, you'll complete the battery's discharge cycle faster.

So, the best solution is a compromise between the two: sometimes run on battery, and sometimes leave it plugged in.Whatever you do, you want to make sure it doesn't get too hot.

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