May 23, 2014, 11:30 AM —
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I looked at my phone at about 9:30 p.m. last night. Battery level: 21 percent. My wake-up time these days is 5:30 a.m., so 21 percent would do. This thing used to give me the 10% warning every day at around 3 p.m. So I poured some Jim Beam Single Barrel over some ice, and quietly toasted the end of a very long journey.
You see, I have been thinking, talking, tinkering, obsessing, advising, and researching battery life for as long as I've had a smartphone–at least 5 years. I've dialed down GPS accuracy, messed with non-push Gmail, set up complicated on/off switches with Tasker and Trigger, rooted my phone, and generally spent far too much time under the hood, when what I really want to do is drive the thing.
Then a few weeks back, while browsing for something else entirely, I found this little Android app, Lux. It runs in the background on your phone and, essentially, takes over the brightness level. It's very smart on its own, but after a few "training" sessions, it knows exactly how bright your phone display should be: in a pitch-dark bedroom, in direct sunlight, at your well-lit office, and everywhere in-between.
But first, a word about your smartphone's display: it gobbles battery life. It wolfs it down like a marathon runner taken from the finish line to a donut shop with great iced coffee. Rhett Alain wrote a beautifully graph-y post for Wired about how brightness affects battery life. That post says, very explicitly, yes: Decreased brightness increases your phone's battery life, in a way you will notice. With all credit due to Alain and Wired, the key graph from Alain's iPhone 4 tests:
Image via Wired.
And the key text, which considers another big factor (data transfer) played against brightness: