The reality of leaving your laptop plugged in

Dealing with battery life and maintenance is a reality of our tech-obsessed world. Everyone wants something that can keep up with their device, and most people agree that it's not fair for a battery to wear out sooner than the rest of the hardware. Just look at what's happening with Apple and their #iPhoneSlow fiasco.

Laptops, because of the amount of performance hardware inside, have some relatively beefy batteries. Technology is always improving, and where battery life used to be atrocious, we're now seeing batteries that can last far longer than the eight-hour workday. Just look at LG's new gram Z980, which manages to cram a 72WHr battery — delivering about 13 hours of life — into a device weighing just over 1kg.

While in the past it was unwise and even dangerous to leave your laptop plugged into an external power source all the time, new laptops are mostly using either lithium-polymer or lithium-ion batteries that won't take more charge than they can handle. Still, there are a few things you should know about leaving your laptop plugged in.

What happens when I leave my laptop plugged in?

What happens when I leave my laptop plugged in?

Instead of continuing to suck up power when at full capacity, the battery in your laptop should be bypassed even if it remains plugged in. This means that power coming from an external source is used directly to power the laptop instead of it first passing through the battery.

Have you noticed when charging your laptop that there's an excess of heat coming off of the bottom? This is a normal byproduct of charging, but if the temperature gets too high or remains elevated for too long, serious damage can occur.

Battery University is an awesome resource that can teach a lot about batteries, with one subject focusing on the effects of heat on Lithium-based batteries.

Temperature chart courtesy of Battery UniversityTemperature chart courtesy of Battery University.

In this chart, we can see that keeping a battery at a certain charge and at a certain temperature over the course of a year can significantly diminish its overall capacity. If your laptop already has a hard time keeping cool, leaving it plugged in and at 100 percent charge is probably a bad idea.

If you're lucky enough to have a modern laptop with a removable battery — some of Lenovo's ThinkPad line is still offering this feature — consider taking it out and relying solely on the charging cable.

What can I do to prolong the life of my battery?

What can I do to prolong the life my battery?

No matter what you do to baby your laptop's battery, it's going to naturally see a decline in performance. When you charge a battery to its full potential — which is, in most cases, to about 4.20V per cell in the battery — you can expect to get a set number of charge cycles out of it. Lowering that voltage in each cell, even by a little bit, can potentially prolong the life of your battery, as seen in this chart from Battery University.

Voltage chart courtesy of Battery UniversityVoltage chart courtesy of Battery University.

Many modern laptops have software that helps deal with keeping batteries healthy. Lenovo, for example, comes with a companion app that will can change the charge threshold. Similarly, Dell's power manager has a "Primarily AC" setting that will also lower the threshold to keep the battery from sitting at 100 percent all the time.

As for some battery basics to keep in mind if you don't have any fancy software, it's generally recommended to keep your battery somewhere between 40 and 80 percent charge and to keep it cool whenever possible.

Why isn't my battery gauge giving an accurate reading?

Why isn't my battery gauge giving an accurate reading?

If you've been using your laptop for a few months (or a few years), you might notice that the battery gauge in the bottom-right corner is no longer giving an accurate reading. You might see that you can two hours left, but 30 minutes into your movie, it powers down.

A recalibration can likely solve this problem! I've already written a guide on the steps required, and the entire process shouldn't take long.

How to recalibrate the battery in your Windows 10 laptop

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