The iPhone’s Power Reserve function saves a small amount of battery life for features like Find My and NFC unlocking to work even when the device is dead. In iOS 18, Apple appears to be enhancing this feature for the iPhone 15 models.
Credits: Apple
As shown on Reddit, an iPhone running iOS 18 can still display the time in the upper left corner even when the battery is exhausted, offering a small but useful upgrade. The battery icon remains visible, and “iPhone is Findable” appears while reserve battery is available.
It seems this feature is exclusive to the iPhone 15 models. Testing on an iPhone 14 Pro Max didn’t show the time, but it worked as expected on an iPhone 15 Pro Max.
Power Reserve has been available on iPhones since the iPhone XR and iPhone XS, so it’s unclear why older devices can’t display the time when the battery is drained.