My son has a MacBook Air which was required for school (a).

However, it sometimes comes dangerously close to running out of power near the end of the school day despite the fact that we've (I think) set it up correctly for low power consumption.

I have suggested taking the power adapter to school, or even getting a second one to carry in his backpack) but apparently many of the classrooms don't provide enough wall sockets, or don't have them handy to the desks.

The local Apple store was spectacularly unhelpful given that they only sell such devices for non-laptops.

What's a good solution for him to plug into his laptop during recess/lunch to get the battery levels up to a point where he'll easily see out the day? Something that would give an extra one to three hours would be ideal.

Additionally, if anyone has some really good tips for lowering power consumption, I'd be happy to hear them though, of course, my question is really about a suitable power device.

(a) I asked if a Linux laptop would be okay and they said yes, but my son would likely get beaten up in the playground :-)

  • Can you share with us what version of macOS is installed and what his energy saver settings are?
    – Monomeeth
    Sep 24, 2016 at 9:18
  • It's up to date El Capitan, I know the screen dims and bluetooth and wifi are both turned off while on battery.
    – user202922
    Sep 24, 2016 at 9:22
  • The school requires a laptop but doesn't provide enough outlets for you to plug into? This is inviting a deluge of the digital version of "my dog ate my homework" as all a student has to do is claim they can't boot their computer when work is due. I would address with the school before trying to jerry-rig a tech solution to a (perceived) operational one.
    – Allan
    Sep 24, 2016 at 12:26

3 Answers 3


I am able to actively use my MacBook Air for around 7-8 hours. It is just a basic advice but it works fine for me:

  • Lower the screen brightness - it's relatively easy to control brightness on MacBook (F1 or F2).
  • Lower the backlit of the keyboard or, as your son is using his laptop in school during the day, it even makes sense to fully turn off the backlit (F5 or F6).
  • When the battery is getting to 25-30% I would quit all the cloud based apps like DropBox, OneDrive or iCloud. In Dropbox you can just pause syncing, which is a really handy feature.
  • Quit all the unnecessary apps. For example if in the class kids had a need to use MS Word and in the next class they don't need to use it, then show your son how to quit programs what he's not using.

I'm not sure if this will give MacBook Air battery two extra hours of life, but I would say from an hour to hour and a half.

One more thing would be somewhat reasonable usage of the battery. Meaning not leaving laptop to charge for hours when the battery is full and vice versa draining the battery all the way to 0% and then start charging it. Li-ion batteries don't like to be fully drained. Charging the battery with the mentioned above mindset could help it live longer.


You don't mention the model of the Air so I'm not sure of its specs but there are two apps that can help prolong battery life and I use both:

Turbo Boost Switcher deactivates the CPU's turbo boost mode, which it's estimated can save 10-20% of battery life.

GFXCardStatus can stop the Mac switching to the discrete (i.e. non-integrated) graphics, and also save power.

I know you're looking for a gadget to do the job here but really just a little common sense and a few apps will do equally well.

  • Discrete uses more power than integrated. Also, no MacBook Airs have a discrete and integrated GPUs, only MacBook Pros do. Sep 24, 2016 at 12:27

As a start, I would suggest your son does the following:

  • Ensure his Energy Saver settings (System Preferences > Energy Saver) are such that they reduce his power usage
  • Adjust screen brightness (System Preferences > Display) or via the F1 and F2 keys.
  • If he doesn't already, get in the habit of not booting the MacBook until he first needs it at school.
  • Reset the SMC (see instructions below)

Reset the SMC

Your computer's System Management Controller (SMC) can also be reset. The instructions for resetting the SMC depend on three things:

  • Does your device run from a built-in battery? (In your case, yes)
  • Does your device run from a removable battery?
  • Does your device just run off power from the wall?

The MacBook Air fits into the first group above. Follow these steps for resetting your SMC:

  1. Shut down your computer
  2. Keep the MagSafe adapter (power cable) plugged in.
  3. Press at the same time shiftoptioncontrol (on the left side of the keyboard) and the power button
  4. Let go
  5. Turn your computer back on with the power button.

Hope this helps. Please report back and let us know.

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