Is It Advisable to Always Have Your Laptop Plugged in?

Is it bad to leave your laptop plugged in all the time? is a question that all laptop users have wondered at some point.

As it happens, the solution isn’t totally clear-cut. So let’s examine.

Recognize the Laptop Battery

Laptop batteries primarily come in two varieties: lithium-ion and lithium-polymer. Despite being distinct technologies, they both use the flow of electrons to generate power in essentially the same way. Additionally, this steady flow is necessary to maintain the battery’s health.

The following claims are accurate (at least in the case of contemporary laptops) for both kinds of batteries: One cannot overcharge a battery. A battery won’t be overcharged if it is left plugged in all the time, even around-the-clock. It will stop charging as soon as it reaches 100% and won’t start up again until the voltage drops below a predetermined amount. A battery will be harmed by being fully discharged. A deep discharge state can occur in a battery if it is left completely empty for an extended amount of time. You may never be able to charge it again, and this could be fatal. (You can jump-start a dead laptop battery using these techniques.) Do we therefore draw the conclusion that you ought to always have your laptop plugged in?

Lithium battery damage-causing items

Lithium-based batteries are inherently unstable, that much is true. They start to degrade as soon as they are produced, and a number of factors accelerate this process. Among them are:

Cycles of charging and discharging: Each battery has a limited capacity for charging and discharging.
Voltage level: A battery’s life is inversely correlated with its charge level, which is expressed in volts per cell.
Elevated temperature: Exceeding 30 degrees Celsius, or 86 degrees Fahrenheit, may result in permanent harm.
Here, the two final points are the ones that most worry us. According to a thorough study by Battery University, high temperatures and voltage levels alone will reduce a battery’s life, and their combined effect will shorten it even further.

Level of Charge or Voltage

100% of the capacity of lithium-ion batteries can be achieved by charging them to 4.20 volts per cell. The battery will last between 300 and 500 discharge cycles at this level.

The number of discharge cycles doubles for every 0.10V/cell drop in charge, up to an optimal level of 3.90V/cell with 2400–4000 discharge cycles. Regretfully, the battery is only about 60% charged at this point. A little over half of a fully charged battery will be used during the runtime.

Warmth

And there’s the warmth. Regardless of other factors, high temperatures—generally defined as those exceeding thirty degrees Celsius—will shorten a battery’s lifespan. It’s not a good idea to just leave your laptop in your car on a summer afternoon.

The effects worsen when you combine the stress of high voltage with the stress of high temperature. According to a study by Battery University, a battery kept at 40 degrees Celsius with a 40% charge would lose 85% of its capacity after a year.

When fully charged, the capacity decreases to 65% in the same circumstances. The capacity of a fully charged battery at 60 degrees drops to 60% in just three months.

The evidence appears to be unambiguous. The battery’s lifespan will gradually decrease if it is kept fully charged all the time. Shortening it significantly faster is possible if you keep it at 100% and expose it to high temperatures.

And keep in mind, there is more to these high temperatures than the environment. Tasks requiring a lot of resources, like video editing or gaming, will raise the laptop’s temperature significantly. Moreover, placing the laptop on a pillow or in a poorly made case will trap the heat.

It’s always a good idea to fix an overheating laptop for the benefit of your battery.

Does Your Laptop Need to Be Plugged in All the Time?

Is the battery of your laptop ruined if you leave it plugged in? It does, indeed. However, daily charging also does that.

In plain English, Microsoft warns against leaving a fully charged laptop plugged in, stating that “keeping the battery charged to 100% all the time can cause it to deteriorate faster.” Although Apple no longer maintains its website, you can still read its advice by visiting the Internet Archive. The business advised against always having a laptop plugged in, proposing:

“A commuter who uses her notebook on the train and plugs it in to charge at the office would be the perfect user. This maintains the flow of battery juice.”

But you don’t have to worry about it as much anymore. With the Optimized Battery Charging setting that macOS now includes, your MacBook will only receive partial charging when it senses that you need it, charging it to 80% when it is plugged in.

Similar functionality is also offered by Windows 11’s Smart Charging feature, though each laptop manufacturer is free to decide whether and how to use it. However, this is not a bug if you notice that when you use your laptop, it is only charging to 80%. It will contribute to your battery’s longer lifespan.

Is It Time to Take Out the Battery?

And finally, when using your laptop on AC power, should you take the battery out completely? As sealed batteries are now found in the majority of laptops, this question is less pertinent than it formerly was.

It appears that different manufacturers have different answers when asked if they are interchangeable. For example, Acer states that although you don’t need to remove the battery when using AC power, you should if you plan to leave it unplugged for a few days. When Apple first started making laptops with detachable batteries, the Internet Archive has information about their advice: never take them out.

It all boils down to the laptop’s power management configuration. Just as some may lower the power when the battery is low, others may do so when there is no battery. This might cause you to perform below expectations.

Make sure to store the battery correctly if you decide to take it out. This typically entails being stored at room temperature and charged between 40% and 80%.

Is Leaving Your Laptop Plugged in a Bad Idea?

If you only use your laptop on AC power, leaving it plugged in won’t harm it in the short term, but after a year, you’ll probably notice that the battery’s capacity has decreased significantly. Likewise, you’ll get through the battery’s discharge cycles faster if you only use it on battery power.

Consequently, the best course of action is to sort of compromise by using it on battery power some days and leaving it plugged in on others, even with the help of smarter software that attempts to limit the damage. Additionally, take care to prevent the battery from overheating.