I have an iPhone SE (3rd generation) with 85% battery health running iOS 26.1. The battery percentage has started behaving strangely: it used to jump between 19% and 20%, but now I sometimes receive repeated 20% battery notifications while the phone is actually at 18%. On one occasion, it then increased from 18% to 21% without being plugged in. What could cause these inconsistent readings, and how can I fix them?
2 Answers
Make sure the phone is updated to the latest available iOS version. Older releases can have battery-reporting bugs, and an update may improve the readings. If you’re hesitant because of regional features or requirements introduced in newer software, you could first check Apple’s update notes and local policy details.
This could be a battery-meter calibration issue, especially with the battery already at 85% health. The percentage is an estimate based on voltage and usage, so it can occasionally move backward or upward when the phone recalculates. Updating iOS may also help if the behavior is caused by a software bug. If it keeps happening, check whether the battery needs service rather than repeatedly draining it to zero.

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