It’s no secret that modern phones rely on rechargeable lithium-ion batteries. A full charge may not last as long as older alkaline AA batteries, but this drawback is offset by the ability to recharge lithium-ion batteries. However, while certain settings can extend the life of your battery per charge, even rechargeable batteries don’t last forever. And, although your iPhone usually tells you how much battery life is left, calibration issues can interfere with this reading.
Battery calibration issues can occur for several reasons. If your phone is new, the system may need time to get an accurate reading of the battery and its charge cycles (the number of times it has received power equivalent to a full charge). Most often this problem will go away on its own, but you can try to force the problem with a hard reboot. To do this, quickly press and release the volume up button, then quickly press and release the volume down button, and finally press and hold the side button until the Apple logo appears. Once this is done, the battery needs to be recalibrated.
Your iPhone may also experience a calibration issue after installing some updates, including upgrading older phones to iOS 14.5 (iOS 14.5 introduced the Battery Calibration tool). Simply go to Settings, then Battery and tap Battery Health. If the system doesn’t immediately display the battery status, it probably just needs a little time to analyze the component. But again restarting the phone can help.
Sometimes the problem is with the battery itself
Since iPhones need to calibrate their batteries after first powering them on, it stands to reason that they go through the same process every time you install a new battery. After repairing your iPhone (or sending it to a repair shop), go to the Parts & Services menu in Settings, then tap Restart and Complete Repair (and again when a new tab appears). Once the phone restarts, follow the on-screen instructions. The phone will reboot, but once it’s finished, your iPhone battery will need to be calibrated. Even after a reboot, you may have to wait a bit, as usual, for the calibration to complete.
If recalibration does not work, you may have used an aftermarket or non-OEM (Original Equipment Manufacturer) battery. While you should stop believing the myth that third-party repairs are poor and void warranties, third-party batteries tend to not work well with the calibration feature. When this happens, the only way to fix the problem is to repair the phone (again) with an official Apple battery. The battery and phone are generally completely safe to use, but you may notice some performance issues. And of course, you won’t be able to track battery health.
