My iPhone's battery life has been terrible on iOS 18 - and I'm not alone

I've been running the iOS 18 betas on my iPhone 16 for weeks, and I'm currently running the betas of iOS 18.1. One thing that's been a constant companion of mine during that time has been a power bank. Why? Because my iPhone 16's battery life has been terrible with iOS 18. 

It turns out I'm not alone. Reddit, Apple's support forums, and social media are awash with people complaining about battery life. 

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Reddit user with the creative name of reddit_sucks12 has this to say:

I just got the iPhone 16 pro max and I noticed the charge left while idle is way worse than my iPhone 13 Pro Max. Literally within like 3-4 hours of being idle while I sleep it lost about 15-20%, which compared to my iPhone 13 Pro Max is abysmal because it loses only a few percentage points. Is anyone else experiencing the same issue and is it related to iOS 18? I really hope so because I don't want the phone to have problems like this.

I've done some digging around to see it there are any commonalities to the complaints. It boils down to an extremely rapid drop in battery -- as much as 50% in a few hours -- and that is able to happen even when the iPhone is not being used. 

Reddit user mlaprise did some tests:

I did an experiment.

I charged my existing 14 Pro and a 16 pro (bought 2 week ago) and used them the exact same way, but they sit mostly unused for 36h. Here's the result.

You can see the 16 Pro discharge going faster in the last 12h. Both have the same background app processing running (none). Not sure what's going on on the 16 Pro. After 36h, the 14 Pro is at 85%, the 16 Pro at 58%.

As usual, people have been turning stuff off, tweaking settings, removing apps and widgets to no avail. No one it seems has come up with a solution. And I'm in the same boat. I've tried a bunch of stuff -- even turning off the always-on display and killing background refresh on a swathe of apps -- and nothing worked. 

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We'll have to wait for Apple to fix this for us.

So this is why I'm carrying around a power bank -- a small 10,000mAh Ugreen unit with wireless charging -- until this issue is resolved.