There have been multiple unconfirmed reports in several corners of the internet about the battery life on the 2016 Macbook Pros being lower than expected. Now, non-profit magazine Consumer Reports (CR) has posted a notice stating that it will not recommend the new machines. The magazine found that the laptops' battery duration varied wildly during testing and was often much shorter than expected, even after installing the macOS Sierra 10.12.2 update.
Initial reports of the problem could be interpreted as a UI issue, since macOS would offer a remaining-time estimate instead of a percentage amount. This method can lead to over-confident estimates given that the machine's usage pattern can very wildly from one hour to the other. Apple recently released an update to macOS that replaced the "time remaining" estimate with a charge percentage indicator to address what it saw as a non-issue.
As it turns out, CR's testing appears to indicate otherwise. The magazine says that there was wild variation between subsequent runs of its browser-based battery draining tests. In CR's own words:
For instance, in a series of three consecutive tests, the 13-inch model with the Touch Bar ran for 16 hours in the first trial, 12.75 hours in the second, and just 3.75 hours in the third. The 13-inch model without the Touch Bar worked for 19.5 hours in one trial but only 4.5 hours in the next. And the numbers for the 15-inch laptop ranged from 18.5 down to 8 hours.
CR goes on to state that the figures above represented only a portion of the test runs, and that it usually gets results that vary by less than 5% between subsequent runs. The magazine says it would normally average the results to present a final score, but in the Macbook Pro's case, "an average wouldn't reflect anything a consumer would be likely to experience in the real world."
The tests were run by leaving the laptops' screen always on at a brightness of 100 nits, with the automatic brightness adjustment disabled. Safari was then used to download 10 web pages in sequence from a local web server until the battery was dead. CR says it always uses the machines' default browser in its tests. After switching to Chrome, CR found that the battery life was consistently high on all six test runs, but notes that it considers that it's "not enough data [...] to draw a conclusion." Affected Macbook Pro users may want to try that one simple trick.