Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.

iLondoner

macrumors 6502
Original poster
Apple’s fixation with thin machines means the new MBP doesn’t have space for a particularly powerful battery. A lot is happening in the technical world to increase battery runtime with more efficient processors, more emphasis on power management, etc., but ultimately you can’t get over the fact that the 13-in touchbar MBP only has a 4315mAh battery against the 7150mAh battery in the 13-in early 2015 Macbook Air.

I have been using a mid-2011 Macbook Air as my mobile notebook, however the battery has gone through more than 1,000 cycles and won’t hold much of a charge, the keyboard has several characters rubbed off and I generally need to update.

In the absence of an updated Air I was looking at the new Macbook Pro, however on 22 Dec 2016, the influential US-based Consumer Reports organisation refused to recommend the new MBP notebooks due to wildly inconsistent battery runtime ranging from as little as 4 to as many as 20 hours on a single charge. Apple claimed the inconsistencies had been down to a bug, subsequently issued Consumer Reports an updated 10.12.3 macOS, at which stage Consumer Reports retested, and on 12 Jan 2017 reported it now recommended the new MBP models.

So I understood the battery run-time problems had been resolved; Apple’s website claims a battery runtime of “up to ten hours” and the small print says this was conducted on a 2.9GHz i5 touchbar model with 512GB SSD and 8GB RAM (in other words exactly the spec I wanted). So I went ahead with my purchase, which I collected 1 Feb 2017.

When I received the MBP I was dismayed to see how quickly the available battery percentage dropped. I was down to zero in just over four hours. Several websites advised this might be a settling in process with background processing by Spotlight adversely affecting the battery runtime, so I gave it a few days to settle down. I also followed the advice to have the display brightness set to just 12 clicks from bottom (per Apple's tests).

But the battery runtime was still much shorter than I need.


If i had purchased from Apple it would have been a simple case of taking the MBP back within 14 days for a no-questions refund, but I had bought it from John Lewis (UK upmarket department store) and I needed some 'proof' that the unit was not fit for purpose. So I decided to test the MBP against my wife’s early 2015 Macbook Air. Apple claims the Air is capable of 12 hours battery runtime, but my wife’s notebook has gone through over 300 battery cycles and the battery is only capable of holding 87% of the original mHa, so you might therefore expect up to about 10.4 hours.

The battery status of 100% comes up once it's more than 95% charged, so don't trust this. I used Battery Health 2 to check the actual charge. So I fully charged both machines, rebooted the operating system, set the display brightness at 75% or 12 clicks from bottom, and then set the display shutoff to ‘never’ so the display would be on constantly. Wifi and Bluetooth both on, Time Machine backups just taken. I started the test at 0934 and it consisted of the two machines being on constantly, and used from time to time to browse the web. The usage on the two machines was approximately the same and approximately only 30% of the time (not continuously like the Apple test). Although at times several browser tabs were open at once, at all times Apple’s battery monitor reported, “No Apps Using Significant Energy.” Apart from the browser, the only app in use on the two machines was Finder, and occasionally, Battery Health 2.

It's worth noting I'm using Google Chrome as the browser rather than Safari as I need the inline automated website language translation that Chrome supplies. Also I want to use the same browser and bookmarks on my iPhone 6 Plus and there's no way to force Safari to always use desktop mode. I understand I might get better runtimes if I switch to Safari, but Chrome is what I use, so that's that.

Ten minutes later I was using the MBP and the screen started to dim and it lowered the brightness to just 1 click whilst I was typing! I set it back at 12 clicks. A little later it reset itself to 14 clicks, so I put it back to 12. And then I noticed the MBP kept increasing the display brightness by itself. It seemed to happen when I hadn’t used to machine for a few minutes. I then realised the Display Preferences was set to ‘automatically adjust brightness’ so I unchecked that tickbox. And I am wondering whether this is the cause of the previous short runtimes, because after 5 hours I still have 46% battery left which would indicate 9 or more hours of casual use could be achieved. I can live with this.

Out of interest, the Air is doing slightly better than the MBP and is showing 52%.

So for me the answer to get a reasonable (9 hours plus) battery runtime is to set the display brightness to 12 clicks (75%) and turn off automatic brightness adjustment. I would of course also change the display shutoff back to its default 2 minutes. Presumably if I know in advance I need a longer runtime, I could turn the screen brightness down another notch or two and maybe get over 10 hours casual use. You could also turn down the keyboard backlight.

I'm planning to run another test with more intensive usage, more apps, but with the display shutoff at 2 mins, and will post the results. So long as the runtime from the second test is at least eight hours I will probably keep the MBP even though I find the keyboard clattery and the trackpad clicking rather tinny. The touchbar if anything is an annoyance as it needs more presses to adjust volume etc. But I love the touchID as a way of unlocking the MBP.
 
Last edited:
  • Like
Reactions: precision01

Sanpete

macrumors 68040
Nov 17, 2016
3,695
1,665
Utah
I'm surprised you got as good a result as you did with Chrome, and with Bluetooth on--why was that on? Otherwise, you seem to have it figured out pretty well. The keyboard backlight has the same issue as the display, by the way--it defaults to automatic brightness adjustment. You can switch that off to keep the brightness as you want it.
 

iLondoner

macrumors 6502
Original poster
I left Bluetooth on because I normally do... ;) And I use AirDrop from time to time. I'll switch it off for the next run.

I don't think I made it sufficiently clear in my first post that the important thing seems to be to uncheck ‘automatically adjust brightness’ in Display Preferences.
 

Sanpete

macrumors 68040
Nov 17, 2016
3,695
1,665
Utah
I don't think I made it sufficiently clear in my first post that the important thing seems to be to uncheck ‘automatically adjust brightness’ in Display Preferences.

Yes, that came through, and it does help, potentially a lot depending on conditions. You can do the same for the keyboard backlight under the keyboard preferences, though it doesn't draw nearly as much power.
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.