I'm currently running Mojave macOS 10.14.14 (18E220a). I purchased a new Macbook Air about the same time (December 2018-January 2019) that the 10.14.12 was introduced.
From the first time I powered up, it's seemed that the battery time when the Air is turned on is much less than it was with a last-generation Air I owned back in the early 2010's. That Air would hold a charge and run the next day, too, almost as good as my Pro. Thi s one stays charged only for a few hours, especially when it's in use.
I've invoked all the power-saving techniques (turning off background-running applications, dimming my screen, liberally using Sleep. They seem not to make a difference.
At the suggestion of a Mac tech, I ran a Diagnostics test; it reported things are fine. My Coconut Battery application reports that the battery is new (as of November 2018), has run only 24 cycles, and is in "Good" condition.
Before I get into this issue further, I'd like to know others' experiences, because ...
• If other Air users are experiencing relatively short battery life, this may be a form-factor issue: perhaps the battery was designed more to fit the ultra-slim Air case rather than to provide maximum power capacity. In that case, I can decide to keep the Air or sell it, depending whether I will regularly be near an outlet or on the road.
• If, however, this is a condition particular to my Air, and others are doing just fine with theirs -- getting the power they need for an extended period of time (say, 24 hours) then I need to have it repaired or replaced.
As a lifelong Apple customer, I know I can count on the community to help out. Thanks for sharing your experiences and insights.
