Open Radar

 
(Also posted to https://www.reddit.com/r/apple/comments/k6x75q/ios_142_has_massive_battery_drain_issues/georyxp?utm_source=share&utm_medium=web2x&context=3 and OpenRadar)


> Turning off Siri on my iPhone 6s massively improved the standby time since upgrading to iOS 14.

Me too, but I had to kill Siri _completely_, not just the options that could reasonably use power on standby, but also Press Home for Siri (specifically siriinferenced) which should only use power when you’ve pressed Home to use Siri, but according to Instruments is using up 29.2% of the CPU. My Battery Health remains at 89%.

Details

I was suspicious of Apple’s quality assurance since I left, and my favorite app is 32-bit only, so I put off upgrading as long as I could (see “The Era of Update Automatically is Over” [https://www.linkedin.com/pulse/era-update-automatically-over-rant-flash-sheridan/]; discussion with the Editor of TidBits [https://talk.tidbits.com/t/hiding-apple-s-big-sur-upgrade-badges/14148/25]). When I updated my iPhone 6S from iOS 10.3 to 14.3 (18C66), I immediately saw a catastrophic deterioration in battery life whenever I unplugged it. My routine has been quite routine during lockdown, so I have some pretty good experimental controls: The vast majority of my unplugged time was either walking down and then up 35 flights of stairs while listening to the Great Courses Plus app or a podcast, or walking across the Upper East Side of Manhattan and then around Central Park, about five miles in all, usually tracking with the Gaia GPS app and checking in with FourSquare. With iOS 10, the battery never got low enough to worry about on the stairs, and usually made it home safely from Central Park.
    On my first unplugged outing with iOS 14, with exactly the same settings as with iOS 10, the phone rebooted without warning before I reached the bottom of the stairs, and the battery seemed to be at 0%, so it was a boring trudge back up. Switching to Airplane mode the next day seemed to help, so the phone was mostly usable on the stairs, though not actually as a phone. 
 
    Trips to the park were even worse, even after I turned off everything that could reasonably affect battery life while locked, including Siri Suggestions on Lock Screen and Lift to Wake (I never enabled Hey Siri.), and giving up on Gaia GPS. Today after killing Siri completely I made it to the Park with allegedly 100% battery. The first time I tried to use the phone, to check in with FourSquare Swarm, the phone rebooted three times; after one of the reboots it displayed the Please Plug Me In icon. I’m now careful to carry a backup battery, so I did, after which the battery read about 90%. It read 52% when I made it home, so I guess my iPhone is actually usable as a phone once Siri is dead.

Disclaimer: I worked in Apple Quality Assurance for seven years, but not on iPhone or Instruments.