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Practical Tips For Taking Care of Your Mac's Battery

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Rechargeable batteries are in all our electronic equipment, yet we know very little about them. In this tutorial we’ll discuss the best methods of keeping your battery at its best and what to do when your battery is showing signs of age.


Apple’s Batteries

Apple uses Lithium-Polymer batteries in all their battery-powered products. Whether it’s an iPod shuffle or a MacBook Pro, the battery technology is the same. Not only does that mean Apple only has to source and use one type of battery, but it means our usage and ways to charge work across all of their product lines. We’ll be focusing on the Mac and how you can best maintain and charge your portable’s battery.

Well focus on the portable Macs
We’ll focus on the portable Macs

Power Adapters

Each portable Mac comes with a power adapter. Depending on the model, its power adapter may be different. For example, here’s a quick run down on the chargers that ship with each Mac:

  • MacBook Air - 45w
  • MacBook Pro 13” - 60w
  • MacBook Pro 15” - 85w

Apples power adapters currently all use the newer MagSafe 2 connector
Apple’s power adapters currently all use the newer MagSafe 2 connector

So, what’s the difference? The larger the portable, the bigger the battery. The bigger the battery, the more power it needs to charge. Each power adapter has a power rating in watts.

What you might not realize is that the above power adapters will work with each Mac, but depending on the combination, they might not work as well.

Metaphor Time!

Imagine you have two buckets of varying size (small and large) and each bucket has a hole that’s proportional to its size. This means the small bucket has a small hole, the large bucket has a larger hole.

Now, we can fill each bucket with water from a small tap. Filling the small bucket is easy, we can fill it faster than the water runs out. Now, if we tried to fill the large bucket with the small tap, the water is just rushing out almost as fast as we can fill it. At this rate, we’d never get it full! So, we need a bigger tap.

That’s better, we can now fill the large bucket. But the large tap is just a tap - we can still fill the small bucket with it, it just doesn’t need to be turned on all the way.

This is pretty much how charging works. Each power adapter provides a certain amount of power. The 45w power adapter will charge the MacBook Air with no problems. It will charge the MacBook Pro 13” as well but it will be much slower to do so. It probably won’t charge the MacBook Pro 15” or just about power it.

One Power Adapter to Rule Them All

Now, if we use the 85w power adapter, we can charge all three portable Macs. You can’t overpower a battery from a power adapter as the battery draws power from the adapter, it doesn’t push the power onto the battery.

So why does Apple ship different power adapters with their Macs? Simple: size and cost. The 45w power adapter is much smaller than the 60w or the 85w and is cheaper to manufacture.

Tip: If you ever need to buy a new power adapter, get an 85w power adapter. They’re usually the same price or very slightly more expensive, but if you upgrade your Mac to will still have a spare!


How Batteries Charge

Don’t worry, we’re not going to discuss the finer points on how battery cells store an electrical charge! We’re actually going to talk about how Apple’s products manage charging.

You may have heard terms such as fast charge or trickle charge. When you start charging a portable Mac, the power adapter is used at almost 100%. This means that (roughly) within the first 2 hours of charging, up to 80% of the battery will be charged. This is the fast charge.

Battery charge graph details how your battery charges over time graph courtesy of Apple
Battery charge graph details how your battery charges over time (graph courtesy of Apple)

After that, the Mac will reduce it’s power consumption more and more until it develops a trickle charge. If we were charging a MacBook Air, it’s power consumption would drop from 45w to 10w and below. Once it gets to above 95%, the battery is stopped charging and the power consumption is reduced to only powering the Mac, keeping the battery at a constant level.

Battery Lifespan

This is something that takes people by surprise: All batteries will stop working. No ifs and buts or candy and nuts. Unlike your Mac, which will have an indeterminate lifespan, a battery has a ticking clock. After enough time and use it will need to be replaced. They’re like tires on a car - eventually they just wear out. So how long do they last?

Cycles

Apple describes their lifespan of batteries in charge cycles. A charge cycle is using a total of 100% of the battery’s power. Apple’s official explanation from their Support page on cycles:

A charge cycle means using all of the battery’s power, but that doesn’t necessarily mean a single charge. For instance, you could use your notebook for an hour or more one day, using half its power, and then recharge it fully. If you did the same thing the next day, it would count as one charge cycle, not two, so it may take several days to complete a cycle.

So, if you use 50% of your battery one day, that’s half a cycle. If you charge it up to 100%, it’s still half a cycle. Once you’ve used it down to 50%, that’s one cycle.

After you reach your cycle count, your Mac won’t suddenly stop working. Apple describes the maximum cycle count as the maximum number of cycles before you’ll notice a huge decrease in the battery’s performance. Your battery may stop working before it reaches the cycle count, it may last a long time after.

Quick Tip: See How Many Cycles Your Mac Has Used

To check your cycle count, you can quickly and easily do the following:

  1. Click the Apple logo (top left of your screen), then hold down the Option key. You’ll see About This Mac change to System Information. Select this option.
  2. On the left-side column, select Power.
  3. You’ll then see Cycle Count under Health Information.
  4. In addition, your Mac will also display the general health of your battery. The expected results are Normal, Poor, or Replace.
System Profiler provides detailed information about your Mac and its battery

System Profiler provides detailed information about your Mac and its battery

So what’s the cycle count lifespan for your Mac? This depends on which Mac you have. If you have a Unibody MacBook Pro (including Retina) or MacBook Air then it’s a staggering 1,000. Before these, it’s between 300–500, depending on your model.

Tip: You can view a full list of all cycle counts over at Apple Support.


Prolonging Battery Life

If you’re finding that your battery life is not as good as it should be, there are a number of things we can look at to resolve this.

Runaway Apps

Chances are there’s an app running that’s using a lot of processor power. You might even notice your portable Mac getting hotter than usual. This isn’t the battery, this will be your Mac using a lot of processing (CPU) power, which generates heat. The more CPU usage and heat generated, the less battery life you’ll get. So, how do we see what is running?

  1. Open Activity Monitor located in Applications > Utilities
  2. Make sure All Processes is selected in the drop down menu
  3. Sort the columns by % CPU from highest to lowest
Activity Monitor helps track down rogue apps using all your power

Activity Monitor helps track down rogue apps using all your power

If you notice anything running exceptionally high (usually 40% or more is a cause for concern) then this will have a big impact on battery life. You’ll most likely notice it’s an app you use daily such as Adobe Photoshop or Final Cut Pro X. If so, then it’s just what you’re using.

However, if you can’t identify the app, this might be what is causing your poor battery life. Google the process name if you can’t identify it to determine what it is - sometimes it’s temporary. Restart your Mac and see if it still remains. If you are sure it shouldn’t be running, you can force it to quit.

  1. Select the process in Activity Monitor
  2. Select Quit Process and choose the option to Quit.
  3. If it still runs, repeat the above process but choose the option to Force Quit.
Activity Monitor can stop an app or process in its tracks

Activity Monitor can stop an app or process in it’s tracks

Customizing Energy Saver

If you’re like me and often leave your Mac idling on your desk whilst you go and do other things, you could be losing a lot of battery life. To manage how your portable Mac operates while you’re away from it, you can use the Energy Saver preferences in System Preferences.

Energy Saver controls how our Mac operates when left alone

Energy Saver controls how our Mac operates when left alone

Energy Saver allows you to control how long your Mac waits idling before it goes to sleep. Within this preference, you have options for when the Mac is running from battery or when it’s plugged in. Under each power type, there are two options for timing - Computer sleep and Display sleep.

Computer sleep refers to how long the Mac waits before it goes into sleep mode. Display sleep is how long it waits before the display turns off. The display is the largest power drain on your Mac so just changing this to go to sleep quickly is enough to increase your battery life tremendously.

Put hard drives to sleep if possible

In addition to sleep timing, we can also ask the Mac to put hard drives to sleep if possible. Spinning hard drives found in non-SSD Macs (so exclude the Retina portable Macs and MacBook Air) generate heat and require a fair bit of power. Having them slow down and stop spinning is a way of saving power. You may notice after a few minutes your Mac makes a whirring noise and there’s a delay of a few seconds when opening an app - this is the hard drive spinning back up again.

Slightly dim the display while on battery power

When unplugging the main adapter, the display dims slightly. Not by much but enough that the power draw is less. You can override this by changing the brightness.

Power Nap

Power Nap (available on SSD portable Macs) allows your Mac to run Time Machine backups, check email and download updates while in sleep mode. It’s great - but should only be used when your Mac is plugged in. You can enable this for battery power as well but it does require slightly more power even when its in sleep mode. If your Mac is going to be doing backups, it should always be plugged in anyway.

Energy Saver can manage both battery and mains power features independently

Energy Saver can manage both battery and mains power features independently

Disable Features

Certain features such as Bluetooth, Wi-Fi and the backlit keyboard are a drain to the battery. If you’re out and about and are using neither one, disable it to save on battery life.

Unplug Unused Devices

If you’re often travelling and use a portable hard drive or USB stick, don’t leave it plugged in. Unmount and disconnect it to save power - your portable storage can decrease your battery life by half!


Keeping Your Battery at Its Best

Before we continue, which method of charging your battery do you think is best?

  1. Always run the battery down before charging it.
  2. Always keep the battery topped up.

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Calibrating Your Battery

For rechargeable batteries such as AAs that are NiMH or Lithium-Ion, each manufacturer recommends ways to keep them charged. NiMH batteries that are commonly used in AA and AAA batteries recommend to use them fully before charging them to avoid symptoms such as memory effect (a fancy name for the battery losing it’s capacity).

Rechargeable batteries often require certain methods of use - thankfully Apple portables dont

Rechargeable batteries often require certain methods of use - thankfully Apple portables don’t!

As with other areas of Apple design, Apple designed their batteries so users don’t need to maintain them. If you’ve got a Unibody portable Mac, there is no right or wrong way to charge it. Keep it plugged in, keep it run down and recharged - it’s all the same. Some people swear by draining the battery every month or two if you don’t already. This is more likely to be a placebo effect, there really is no method to keep your battery healthy!

If you own a portable Mac that does have a removable battery, you do need to occasionally calibrate it. This is to ensure the Mac always knows what the capacity of the battery is so it can ensure 100% really means 100%. From Apple’s support document on calibrating batteries:

  1. Plug in the power adapter and fully charge your PowerBook’s battery until the light ring or LED on the power adapter plug changes to green and the onscreen meter in the menu bar indicates that the battery is fully charged.
  2. Allow the battery to rest in the fully charged state for at least two hours. You may use your computer during this time as long as the adapter is plugged in.
  3. Disconnect the power adapter while the computer still on and start running the computer off battery power. You may use your computer during this time. When your battery gets low, the low battery warning dialog appears on the screen.
  4. At this point, save your work. Continue to use your computer; when the battery gets very low, the computer will automatically go to sleep.
  5. Turn off the computer or allow it to sleep for five hours or more.
  6. Connect the power adapter and leave it connected until the battery is fully charged again.

Yep, it says PowerBook! This is because the batteries Apple have used since the days of the PowerBook didn’t change until they went Unibody.

Now, there are ways to ensure you get the best battery life during the day.


When the Inevitable Happens: Servicing Batteries

Once your battery is getting towards the end of its lifespan, your Mac’s battery icon will change from the default black to red. Clicking on it will display the message Service Battery.

Service Battery will require you to arrange for your battery to be checked by Apple

Service Battery will require you to arrange for your battery to be checked by Apple.

On older Macs, you can simply buy a replacement battery and fit it yourself. On Macs manufactured before 2009, most of them had a removable battery you can buy from Apple or any Apple service provider or retailer. But what about Unibody machines? Those batteries are non-removable!

All batteries will stop working. No ifs and buts or candy and nuts!

Well, actually no. They’re non-serviceable by users. This doesn’t mean they can’t be removed or serviced, just not by an average user. You can visit an Apple Store or contact AppleCare to have the battery serviced.

Tip: It’s highly recommended not to attempt to change the battery yourself and to let an Apple repair technician or Genius do it for you. Because the batteries are no longer user replaceable, they have far less protection in their casings (since the Unibody casing protects it) so one slip of the screwdriver with your portable Mac opened up and you could puncture the battery, causing a very nasty mess and potentially injury to yourself.

Battery Servicing

All Apple Stores have diagnostic tools to quickly test the battery. Batteries nowadays are extremely smart. They contain all kinds of information such as their charge times, usage and more. The cycle count and all these times are stored within the battery’s own circuitry.

Apples Unibody portable Macs are serviceable by Apple technicians

Apple’s Unibody portable Macs are serviceable by Apple technicians

When the battery is tested, the Genius at the Apple Store will get an instant notification as to whether the battery is faulty or not. If it is, they’ll service it under warranty or AppleCare. If it’s above its maximum cycle count, then it’ll be a paid-for service since the battery isn’t faulty, it’s just worn out.

Tip: A battery is classed as a consumable, just like printer ink. If your battery is just worn out (has exceeded the maximum cycle count), it’s not eligible for any warranty repair or under AppleCare in the same way worn tyres on a car aren’t covered under the manufacturer’s warranty.

If you find your battery needs to be replaced and it’s out of warranty, Apple offers a flat-rate replacement fee. Pricing ranges from $129-$199 depending on which portable Mac you have. For more information, view the Apple Support document which contains all the current pricing for their products.

Tip: Apple offers battery replacements on all their products that contain a non-removable battery. This includes the iPhone, iPod and iPad.


Wrapping Up

We’ve detailed plenty of ways to keep your battery in great shape as well as what to do when the battery shows its age. Servicing the battery is a quick and simple option if it needs it and making sure your Mac is sleeping properly will help get you the best battery life possible.

If you’ve got any more advice or tips to save battery life - post them in the comments!

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