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  1. Computer Skills
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Computers

How to Conserve Battery Life on a MacBook

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MacBooks have some of the best battery life of all laptops: the 13“ MacBook Air is meant to last up to 12 hours but often lasts longer, while even the 15” MacBook Pro should stay running for at least nine hours as long as you aren’t doing anything too strenuous. 

Still, there are times—such as when you’re travelling—when you want to ensure a MacBook stays running for as long as possible.

Conserving battery doesn’t mean not using the Mac or not doing what you want with it, it’s just about making sure that no battery life is wasted. In this tutorial I’ll show you some of the ways you can do that.

Put the Mac to Sleep When It’s Not in Use

One of the simplest ways to conserve a Mac’s battery life is to have it go to sleep when it’s not doing anything. All modern MacBooks have an SSD so they wake up extremely fast; putting the computer to sleep no longer involves waiting ages for it to come back to life whilst it reads data from a slow hard drive.

You can do it just by closing the lid on the MacBook; however, it’s better to configure things to happen automatically.

In the Energy Saver Preference Pane you can configure how long before a Mac’s display, and the computer itself, go to sleep. The shorter the interval, the faster the Mac will go to sleep once you stop using it, and thus the more battery life you’ll save.

energy saver
The Energy Saver preference pane.

The problem with relying on OS X’s built in energy saving options is that they are essentially a dumb tool; if you step away from the Mac for the allotted time, it goes to sleep regardless of what else is going on. Files downloading from the Internet? Watching a movie? Final Cut Pro Project exporting? It doesn’t care.

To get more control over when a Mac sleeps you need to turn to third party apps.

Caffeine

Caffeine—which I covered when I looked at simple solutions to common Mac problems—is a free menubar app that gives you more control over when a Mac sleeps. 

You can set a short interval in the Energy Saver options and then, when you need the Mac to stay on for longer, activate Caffeine to keep it awake.

Caffeine, however, is only a partial solution. Once the app’s activated, the Mac will stay on until its battery dies. Once the Mac’s done whatever you needed it to do, you want it to go to sleep.

Should I Sleep

Should I Sleep is basically Caffeine on steroids. Rather than being a binary on-off app, Should I Sleep uses a number of sensors to determine when the Mac should go to sleep.

It costs $1.99 for the Face Detection sensor and additional sensors are $0.99 in-app purchases, although they can all be bought for $2.99.

Should I Sleep has six sensors:

  • The Face Detection sensor uses the Mac’s front-facing camera to check whether or not someone is sitting in front of the Mac; if they are, it prevents it from going to sleep
  • The Camera Motion sensor uses the same camera and checks for motion, if there’s any the Mac won’t sleep
  • The Download Monitor keeps an eye on the Mac’s network usage, if it’s doing something it keeps it running
  • The Processor Usage monitor does the same thing, except for the Mac’s CPU
  • The External Display Sensor keeps the Mac running if it’s connected to an external display
  • Finally, the Sound Activity Sensor monitors the background noise and if it’s above a certain level keep the Mac awake

Combinations of Should I Sleep sensors give you almost total control over when the Mac sleeps and when it doesn’t. If you want a file to download before the Mac goes to sleep, you use the Download Monitor. If you’re watching a movie, you use a combination of Face Detection, Motion Detection and possibly the External Display Sensor.

Whatever reason you have for keeping the Mac running for a short while after you stop using it, some group of Should I Sleep sensors should be able to handle it. 

More control over when the Mac sleeps means you have more control over its battery life.

Switch to Safari

Every time a comparison is run comparing a Mac’s battery life when it’s running Google Chrome with when it’s running Safari, the result is the same; it lasts hours longer with Safari. Take this recent article from the Verge.

safari
Switching to Safari can have a surprisingly large impact.

In a battery test using the 13" MacBook Pro with Retina they got 13 hours and 18 minutes of web browsing with Safari compared to 9 hours and 45 minutes with Chrome. 

Most of the time, you probably won’t be using the Mac long enough between charges to notice the difference—ten hours is still an extraordinarily long time for a laptop to last—but it is there. 

If you do a lot of browsing with the Mac, consider switching to Safari. You’ll instantly get a few hours of extra time online.

Watch Active Applications

As well as switching the web browser, examine which apps are running in the background.

The Energy tab in OS X’s Activity Monitor provides an overview of what apps are having the most impact on the Mac’s battery life. Here you might find some surprising culprits. 

For example, apps that sync in the background, like Dropbox, can have a large effect. If you want to conserve battery power ,and don’t need the files Dropbox is trying to sync, quitting the application can greatly increase how long you can keep the Mac running. 

There are plenty of other background apps, like this, that may be draining the Mac’s battery life without your being aware.

Activity Monitor
The Energy tab in Activity Monitor let's you know what apps are draining the battery.

You should also think about what work you do while the Mac is running off its battery.

Powerful apps, such as Adobe Photoshop or Final Cut Pro, use a lot more juice than simpler programs. 

If you’re going to spend some portion of your workday with the Mac running on battery power and another portion with it charging, it’s best to save the energy hogging tasks until you’re connected to the power.

Dim the Display

One of the biggest power draws on a Mac is the display. If you’re only doing simple, low energy tasks, it’s probably what’s draining the battery the most. 

When you're working on battery power, dim the screen on the Mac as much as you are comfortable. You should never dim it to the point where you need to strain your eyes to see, just to lowest value where you can easily use the Mac.

Similarly, if the Mac has a backlit keyboard you should dim it fully. While it might only save a tiny bit of power, when it comes down to it, that might be the difference between finishing your work and running out of battery. 

Unless you’re working in the dark and need to see the keyboard, the backlight is just a waste of power.

Conclusion

In this tutorial I’ve looked at some ways to conserve battery on a Mac. Conserving battery isn’t about barely using it to eke out the longest possible runtime, it’s about managing the Mac so that you use it how you want without wasting battery life.

Apps like Caffeine and Should I Sleep give you more control over when it goes to sleep. A simple change in web browser can gain you hours of battery life. Watching which apps are running means the programs you don’t need, won’t use all the power. 

Finally, simple tweaks to the brightness of the display and keyboard backlight can have a dramatic effect.

If you’ve any tips for conserving a Mac’s battery life, please let me know in the comments.

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