Should You Keep Laptop Plugged in or Use It on Battery Power?

Quick Tips

• Modern laptops automatically cut off charging once the battery reaches its maximum capacity.
• If heating is not an issue, keep the battery inserted into the laptop.
• Charge the battery to at least 50%  but not more than 75%.

Can You Overcharge Your Laptop Battery?

Every battery can only sustain a finite number of charge and discharge cycles, after which it starts wearing off quickly.

Two types of batteries—lithium—ion and Lithium—polymer—are prominently used to power all new laptops worldwide, and although they are built using different tech, they function similarly.

But does charging it hurt its battery life if you are using it?

A lithium-based battery can not be overcharged even if it is left plugged in at all times because as soon as it is fully charged (100%), the internal circuit prevents further charging until the voltage drops.

While overcharging isn’t possible, keeping your laptop battery discharged is an issue. Keeping your battery in a discharged state for long periods can damage its potential to charge again or charge at all fully.

However, the answer to keeping your laptop plugged in isn’t as straightforward because it depends on several factors.

Lithium batteries are known for their unstable properties. Several factors, such as voltage level, temperature, and the number of times they have been recharged, contribute to their deteriorating quality over time.

High voltage levels while charging can shorten a battery’s life, and temperatures over 30° Celsius can also severely damage it.

Improve the Battery Discharge Cycle

According to a study by Battery University, you can prolong your battery’s discharge cycle by not charging it to 100% (4.2v charge/cell).

Based on the table below, charging your battery to 85-90% will double its discharge cycle from 300-500 to 600-1000.

Similarly, an even lower charge at 70-75% (4v charge/cell) will quadruple the discharge cycles. But this will also mean the battery won’t last as long on a single charge.

The study concluded that the optimal charge voltage for Lithium batteries is 3.92v/cell, roughly equivalent to 60% of battery charge.

Excessive Heat Causes Irreversible Damage

Temperatures over 30° Celsius can shorten a battery’s life. Even leaving your laptop at room temperature or outdoors that exceeds the temperature mentioned above can damage its battery.

Lithium-based batteries’ total charge-holding capacity starts deteriorating fresh out of production and will inevitably decrease over a year. However, exposing them to elevated temperatures further reduces their ability to hold a charge.

The study also outlines that the most damaging condition for a battery is when it’s stored at full charge at elevated temperatures — above 30° Celsius.

Storing a battery charged at 100% at 60° Celsius temperatures will result in the battery losing over 40% capacity in just three months. While storing it at 40% charge at the same temperatures will make it lose 25% charge holding capacity over a year.

Operating your laptop at high temperatures while plugged in at 100% battery charge isn’t recommended as well.

Temperatures don’t mean the ambient temperature but the battery’s temperature, which might also be affected if your laptop is kept somewhere where heat is trapped—such as a pillow or in a poorly ventilated spot.

Remove Battery When Plugged In? Not Really

Until heating isn’t a factor, you do not need to remove the battery when the device is plugged in or worry about the battery overcharging.

Every company has its recommendation on whether or not to fiddle with the battery pack or leave the device plugged in when the battery holds a complete charge.

• HP states that a laptop shouldn’t be subjected to continuous charging for more than two weeks at a time.
• Dell has no issues if you always leave the laptop plugged in.
• Acer wants you to remove the battery when plugged in at all times.
• According to Apple, “Leaving your portable plugged in all the time isn’t recommended, and an ideal user would be a commuter who uses her notebook on the train and then plugs it in at the office to charge. This keeps the battery juices flowing.”

There is no straightforward answer to whether or not you should keep your laptop plugged in at all times; it depends on the situation.

Keeping your system plugged in while the battery is at 100% charge won’t be a problem if you’re working at cool temperatures. However, if the temperatures are elevated and the battery is fully charged, it can potentially damage the battery.

If you remove the battery, don’t store it in a discharged state. Please charge the battery to at least 50%  but not more than 75% to avoid falling into a deep discharge state, which can sometimes be irreversible.

Your battery will not last forever, and eventual deterioration of its charge-holding capacity is inevitable. You can prolong its discharge cycle and decrease the speed at which it loses its ability to hold a charge.