For the last few months I was very unhappy with my iPhone 13 Pro battery.

It was discharging way too quick. How quick? After 10 hours after unplugging I usually got "battery low" alert. I didn't feel my usage throughout the day would be enough explain it.

I tried to troubleshoot it, but to no avail. The only hint I got was "Find My" app, that was using 100% of the battery when inspecting part of the available battery slope. I tried various strategies but wasn't able to fix it.

One day I barely touched my phone but it still drained whole battery. There was an StackOverflow post about someone using Instruments to figure out what was happening.

So, I installed XCode, put phone it in development mode (so I could connect to it), and ran Instruments with ActivityMonitor log:

Screenshot of Apple's MacOS Instruments Activity Log
`AccessibilityUIServer` seemed off. While it's "at point" CPU usage was small it contributed to 50% of CPU time. I wasn't sure what it might be, but due to further investigation decided to check Accessibility configuration.

When I opened the pane I immediatelly knew what was happening: Sound Recognition.

Long story short for unaware, iOS has Sound Recognition feature whichallows it to recognize sounds like coughs, baby cries, alarms and such. It's a fun feature I toyed with to get some data to look at or when I wanted to listen to music while waiting for someone.

...and I forgot to turn it off 🤦‍♂️

Unfortunately iOS keeps shows only last 24h with detailed data, so I don't have a lot to show, but that's how the Screen Time/Battery usage wasreported for the 10 days.

Day Screen on Screen off Battery usage
(approx)
1 1h 54m 13h 55m 80%
2 1h 34m 22h 22m 100%
3 2h 27m 3h 41m 95%
4 2h 29m 5h 21 110%
5 3h 36m 3h 38m 125%
6 47m 27m 95%
7 1h 40m 39m 95%
8 1h 43m 2h 8m 90%
9 4h 4m 1h 1m 125%
10 1h 19m 28m 20%

I was resolving issue on day 9th and day 10th is the one with feature disabled. Problem solved!

Summary would be that it was me, the user (what a surprise), who got into situation that drained energy from their device.

I believe, however, that issue also lies in Screen Time / Battery Report which didn't include system-provided yet optional features in the report which made it very hard to find.