Facebook Says It's Fixed the Problem That Was Draining Your iPhone's Battery

A week after iPhone owners first started reporting that Facebook's iOS app was draining their batteries, the company says it's solved the mystery of what was causing the power suck and fixed the problem with an update.

Circa co-founder Matt Gilligan wrote a Medium post last Thursday describing how the Facebook app was depleting his battery, even when background refresh was turned off—which is supposed to stop the app from refreshing content in the background. Nobody could figure out what was causing the issue, and Facebook would only say the company was looking into the issue. Now, the company has come forward with an explanation.

Ari Grant, Facebook's engineering manager, wrote in a Facebook post today that the company has determined the issue was caused by two things. The first is something called "CPU spin," which Grant described as working like this: "A CPU spin is like a child in a car asking, 'Are we there yet? Are we there yet? Are we there yet?' with the question not resulting in any progress to reaching the destination." This repeating process causes the battery to drain, he wrote.

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The second issue was with how the app manages audio channels in iOS. According to Grant, when you watch a video in the Facebook app and then close it out, the app sometimes leaves an audio channel open and running. This feature is often used by music streaming apps, but in Facebook's case, it was unintentional and resulted in some serious battery drainage.

"We are sorry for any inconvenience this has caused," Grant wrote. "We are committed to continuing to improve the battery usage of our app and you should see improvements in the version released today."

Grant's post both confirms and puts to rest some previous speculation as to what was causing the drain. Audio channel management was one popular theory, and it turned out to be true. A security researcher that Motherboard spoke to examined the app's code and determined that location tracking might be to blame, which, Grant writes, is actually not the case.

As for what this means for you and your phone's battery—and what more important relationship is there, really?—the latest Facebook update should allow you to stay together just a little longer during the day.