MacMost Now 206: Monitor Your MacBook Battery

You can use the Mac's System Profiler to closely monitor your MacBook battery. You can view the charge capacity, current charge, age and current power use. You can use this to make adjustments to your behavior to get more life out of a charge.
Video Transcript / Captions
Closed captioning for this video is available on YouTube: MacMost Now 206: Monitor Your MacBook Battery.

Gary Rosenzweig: Hi, this is Gary with MacMost Now. On today's episode, let's take a look at how you can monitor your MacBook's battery very closely.
So I've been a PowerBook and MacBook user for years and one of the things we have to worry about is, of course, the batteries. Replace them every once in a while, monitor their condition, and also keep tabs on how much power is left if you're not plugged into the wall.
So there's actually a really good way to do this that most people don't know about. In System Profiler, which is an application that comes with your Mac, you can go ahead and monitor very closely exactly how much power your battery has right now, how much total capacity it is and how much you're using.
So you run the System Profiler and look for the power settings and then look for battery information under that. And that gives you a whole bunch of different information you can use to monitor your battery.
So one of the first things you want to look at is the condition. Now it should say 'Good'; Good is the standard, it means your battery is operating fine. If it says anything other than Good then you probably have a problem with your battery and you want to get it replaced or take it into the Apple Store.
Now the next thing you want to look at is you want to look at the remaining charge capacity and the full charge capacity. So the full charge capacity is actually a moving number; it's telling you how much charge your computer thinks your battery has when it's fully charged. So as the battery gets older, this number is going to get lower. So you can track it; maybe keep notes and see how your battery is wearing over the months.
And the remaining charge capacity tells you how much is in there right now. Now in this case it's plugged in and fully charged so the number should match.
Now the next thing you want to look at is the cycle count. Now the cycle count is basically how many times your battery has been fully charged. Now Apple says that a battery that has been charged about 300 times is starting to get old. So you're going to start to see degradation of service at about 300. If your battery is much, much older than that, you probably want to start to make plans to get a new one.
So here's what it looks like when you unplug your MacBook from power. The first thing you notice is that the remaining charge will actually start to decrease, of course, and be less on the full charge as it's shown here.
The other thing is that the amperage now is a negative number. Instead of power flowing into the battery, power is leaving the battery. Now this number is something that you can really closely monitor. For instance, if you turn down the brightness on your computer, this number will drop. Now system profiler doesn't update automatically; what you need to do is hit command r with system profiler showing and you'll see the number change. It takes a few seconds for a change to take effect.
For instance, you turn the brightness down, it takes about 5 or 10 seconds for you to see a new number under amperage. But the cool thing is that you can really monitor your battery power usage. So for instance, say you're on a long plane trip and you want to stretch that battery power out. You can see what happens when, say, you lower the brightness, when you play music and you play it at a lower volume, if you quit certain applications what happens, if you're viewing some sort of animation or video.
You'll see all these changes reflected as long as you keep hitting command r and waiting a few seconds to see the changes take effect. Then you can kind of figure out an optimum solution. For instance if you are just doing some simple writing maybe you'll figure out the lowest brightness you can stand and an application that uses the least amount of battery power as possible to stretch out the amount of battery time that you have on a long plane trip.
Now if you'd rather not use the system profiler but maybe a third party application, there's a lot out there. For instance iStat and iStat Pro both show this type of information there in various formats. You can get it, and it's free, at
There's also a variety of other third party applications that will monitor your battery, giving you basically the same information that you see on system profiler but maybe a little easier for you to access.
Now all the new MacBooks have new batteries of course and the 17 inch and of course the MacBook Air have batteries that are not really removable, although it turns out that you can actually open up the case and remove them or get easy replacements at Apple Store. It's just that you can't really swap them on the fly. So this type of application is going to be more valuable than ever, just to make sure you know exactly how much power you've got and how your battery is getting; whether it's worth trying to get a replacement for it.
Until next time this is Gary Rosenzweig with MacMost Now.

Comments: 9 Responses to “MacMost Now 206: Monitor Your MacBook Battery”

    9 years ago

    regarding battery life i know this question might have pop up somewhere before but once and for all should i leave the macbook pro plugged in all the time or should i unplugged it as soon as i get full charge and plugged it again when battery power gets low. thanks

      9 years ago

      Keep it plugged in.

        9 years ago

        thanks for the advise… much obliged

        8 years ago

        I disagree, sorry – asked someone on the Apple genius bar the same question and he said to charge and discharge it, or else the battery cells weaken, which decreases battery life. he said, though, that if you use it a lot, 3 times a week is enough to drain and refill the battery.

          8 years ago

          What you are talking about is calibrating your battery for longer life. While I agree that doing this every once in a while is a good thing, doing it 3 times per week for no reason is NOT. That would run it through needless “cycles” and it won’t last as long. Apple recommends doing it once every one or two months ( Of course for most MacBook users they do it once a month through natural use, so it isn’t necessary to do anything special.
          I maintain that “calibrating” the battery once a month vs. natural use, where it might get drained once a month or more anyway, is about the same, give or take a few percent. But people stress about getting every bit of life out of a battery way too much.

    9 years ago

    All macs ? or just mac pro? I have a macbook and i was wondering the same thing

      9 years ago

      My advise would be the same for MacBook and MacBook Pro.

    8 years ago

    Can u make a video on “How to improve your battery life?”…typo….tips and tricks or only tips on how to improve your battery???Thank you and looking forward for that.

      8 years ago

      Besides the info in this video, I’m not sure there is much to say. I’m not a big believer in many of the techniques people use to extend battery life. I see people wasting tons of time and effort trying to get 1 or 2 percent more. I think people should let the hardware and software in their MacBooks handle it, and they should use their Macs to optimize their time and energy, not the battery’s time and energy.

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