I’ve been using an older (2011) 11″ MBA with very poor battery life (~2hrs?) and have been very much looking forward to upgrading to a Haswell MBA for quite a while.
TLDR: battery-life is much improved, however falls far short of the claimed 9 hours for my 11″ MBA. I get about 6hrs max (6hr 12min) and in regular usage, less.
The specific model I have is the top-of-the line MacBook Air “11-inch, Mid 2013” with a 1.7GHz Core i7 processor, 8GB RAM, and 512GB SSD. Here’s the iFixit teardown. Anandtech did a recent test comparing Core i5 to Core i7 battery life (the Core i7 is very slightly better under low workload, and is 13-18% worse under medium-heavy workload).
The battery is spec’d by Apple at 7.6V and 5100mAh – 38.75Wh, 8.08oz. The battery had a Cycle Count of 6, a Max Capacity of 5326mAh (4.4% above spec) and an initial voltage of 8.545V – that’s to say it’s in better-than-spec condition.
Display was set to 75% for testing with the keyboard backlight off, wifi on, screen sharing off, SSH on.
Background apps include: Dropbox, iStat Menu, Evernote Helper, MiniBatteryLogger, and memcached (64MB, not being used).
The 6hrs was spent almost entirely with light web browsing w/ relatively low CPU/disk/network usage. It’s too bad there isn’t anything like Android’s battery/activity tools built into OS X (I suppose you could script something to sample/aggregate activity but that’s sort of beyond the time I really want to spend on this since I can’t really do much w/ that data).
I used MiniBatteryLogger 1.8.5 for getting battery stats and for graphing. Also here’s some clips at the end from iStat Menu:
For those interested, here’s the raw battery data export.
UPDATE2: The Verge published an 11″ review where they claimed to get 9-10hrs+ of battery life (cycling through popular websites at 65% brightness). gnoring any critiques on the battery testing methodology, I really wish I could find the disparity – getting that sort of battery life would be really nice… Things that could possibly be responsible for the difference:
- Actual browsing uses a lot more network than refreshing a series of mostly cached sites
- FileVault chews up a lot more power
- Wifi signal/AP distance/type has significant difference in power consumption
- Some long-running process, either ClipMenu, iStat Menu, Dropbox, SSH is causing my laptop to function way less efficiently than it should.