iPhone battery draining so fast when screen is off

[Clayton630]

I’m using an iPhone 14 Pro Max and I never charge my iPhones overnight in order to preserve battery health (which is still at 100%). I never lost more than 1 or 2% per night but since iOS 16.3, I am now losing between 20 and 30 percent per night ! This is really huge and my iPhone says no process is active in the background during this period of time. I tried updating to iOS 16.3.1 and 16.4 but non of them fixed it. I am now using the beta of 16.5 cause I was hoping it might fix my problem but it didn’t. Does anyone else have this issue ? I’m afraid they never fix it like they did with the battery drain issue introduced on iPad with iPadOS 15

 

[revs]

This could be all sorts of things. You could try a full reinstall rather than an update, might work.

In the past I've seen similar behaviour, one of the causes was the Mail app - seems like maybe it got stuck downloading an email, and spend its time constantly retrying over and over. But the battery stats showed mail using battery, so that was how I worked it out.

It's one of those annoying issues, and probably specific to your device and software/data. If I were you, I'd be doing a backup, then a clean re-install. See if it persists. If it doesn't, then restore from backup, then check again.