With continued concern about the battery life of the 2016 MacBook Pro models, ArsTechnica has written a short piece outlining some of the obvious and less obvious reasons many users are experiencing as little as half the usage time claimed by Apple.

There have been anecdotal reports of battery life being improved by the 10.12.2 update (hands-on video), but the site reports that Apple ‘told us repeatedly and emphatically that it had taken no specific steps to improve MacBook Pro battery life in this update.’ There is, the piece suggests, a likely explanation for these reports …

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ArsTechnica says that the perceived improvement is most likely coincidental, citing a factor we mentioned a couple of days ago.

Apple’s Spotlight indexing service crawls through all of that content to make it easier to search through later, and iCloud syncing for iCloud Drive, the iCloud Photo Library or Photo Stream features, and other features can also make for a lot of uploading and downloading. Battery life in the first day or two may not necessarily be representative of normal battery life once everything has settled down.

This could also help to explain some of those reports that battery life has improved since the 10.12.2 update landed. It could be that the update’s installation coincided with the end of those first-time Spotlight and iCloud operations.

While it’s obvious that Apple’s standard battery life test does not reflect real-life pro usage of the machines, the piece says that there are three other reasons users may see far less battery life even after these initial processes have completed.

First, and most obviously, Apple has dramatically reduced the battery capacity of the new machines.

The 13-inch model drops from 74.9 WHr to 49.2 WHr and the 15-inch model falls from 99.5 WHr to 76 WHr. That’s a 34 percent and 24 percent reduction in capacity, respectively.

Second, while the new Skylake processors are described as being much more power-efficient, this is only really true when they are idling or under extremely light load.

Sometimes the newer chips consume a tiny bit less power than the older ones, and sometimes they use a little bit more, but they’re broadly comparable […] The less idle processor time you have, the less Intel’s recent power optimizations can help you.

Third, all 15-inch machines have more power-hungry discrete GPUs, and you can’t choose when to use them.

There’s no integrated-only option for people who would like to prioritize battery life over external display output. The laptops will dynamically switch between the integrated and dedicated GPUs to save power, and while it does help, switchable GPUs are still a kludgy solution to the problem. There’s no way to turn the dedicated GPU off entirely, so it’s still going to be kicking on and off depending on what you’re doing […]

As of Sierra it doesn’t appear to be able to handle manual graphics switching on any system. So 15-inch Pro owners have to put up with increased GPU power consumption.

ArsTechnica agrees with my own view that the new Touch Bar is unlikely to be a factor.

Having a whole separate screen and SoC inside the MacBook using your battery does contribute to your overall system power use, but let’s put that in context […] The Apple Watch Series 2 can last well over a day on a 1.03WHr battery, just a fraction of the 74.9 WHr to 49.2 WHr capacities of the Pro batteries. It has an impact, but it’ll be relatively minor compared to the rest of the system.

The Touch Bar display is of course larger and on for much more of the time, but even so, as I said before, ‘OLED is more power-efficient than LCD, and it switches off when you’re not actively using the machine, so really it’s going to be the equivalent of the screen size being a tiny bit larger.’

The piece suggests four things you can do to maximize battery life:

  • Reduce screen brightness
  • Close unused apps & tabs (especially ones that frequently perform a background sync)
  • Use Safari rather than Chrome
  • Use Activity Monitor’s energy tab to identify other power-hogging apps

Our own poll of battery life found that the largest group of owners were reporting five hours or less. Personally, closing unwanted apps when on battery power, I’m fairly consistently seeing 6-7 hours of light usage – writing and web-browsing.

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