Force your MacBook to only charge up to 80 percent (and why you should)

Batteries are not magic. It’s chemical. Like most things built by humans, they wear down over time. I don’t need to tell you this, anyone who owns a MacBook knows that battery life gets worse with age. But what if I told you that it is possible to slow down this process?

One common tip is to only charge your devices up to 80 percent most of the time. Battery University, which is funded by a consulting firm that helps large companies get more out of batteries, suggests this based on its research. So does the National Renewable Energy Laboratory.

But how do you actually follow this advice? The good news is that your MacBook already does this, and there’s a great free app that allows you to go even further.

Built-in optimization

Your Mac is designed to only charge up to 80 percent, at least in some circumstances. By default, Macs recognize your charging and usage routines and charge the battery accordingly. According to Apple, “Your Mac delays charging by more than 80 percent when it predicts that you will be plugged in for an extended period of time, and aims to fully charge the battery before unplugging it.”

What does this mean? Well, for example, if you tend to charge your laptop overnight, it will charge your Mac up to 80 percent, and then wait until the morning to charge the last 20 percent. The idea is to reduce the amount of time the battery is fully charged in such a way that you won’t even notice.

The nice thing about this feature is that you don’t have to do anything to maintain battery health. Your Mac is already doing its best to charge up to 80 percent only when your routine suggests it won’t affect you.

(This feature is actually a macOS setting that is turned on by default. You can find it at Settings > battery > Battery healthwhere you can turn off this protection setting, although you should keep reading to see if this is best.)

If you don’t like to think about how charged your battery is, stop reading again. If you want more control, I have some tips.

Control the free app

There are some potential problems with Apple’s approach. The first is that you are not in control. You might discover, for example, that your MacBook isn’t fully charged if you wake up earlier than usual to catch a flight, and then find yourself stuck with a partially charged battery on a long travel day.

For me, the biggest issue is that my daily battery usage is not routine. I do a lot of my work at my desk, with my computer plugged into my monitor, which also charges it. I like to move around my space throughout the day, which means I unplug at random times. Sometimes I put my laptop in my bag and work in the library or café. It would be nice to be able to make sure I’m fully charged when I do this.

You get the idea: not everyone’s actions are predictable. If this sounds familiar, and you want direct control over your MacBook’s charging, I recommend the free and open source app called Battery.

This application resides in your menu bar and forces your laptop to only charge up to 80 percent. You can allow full charging at any time, by clicking on the menu bar icon.

This will require a little planning and attention on your part. You’ll have to remember to enable full charging before you need it, and then turn the limit back on when you know you won’t need it.

But for someone like me, who mostly uses his MacBook at his desk, it seems like a way to ensure my battery stays in good shape for as long as possible.