How to diagnose a battery or charging problem on the iPhone 16

The phone won't turn on or the screen stays black

Before assuming a serious fault, Apple recommends trying a wireless charger, cleaning the charging port with a soft, non-metallic brush, checking that the power adapter used is actually suitable, then leaving the iPhone on wired charging for at least ten minutes before trying to restart it.

Battery draining unusually fast

Rapid depletion, an inability to hold a charge, or an immediate shutdown as soon as the cable is unplugged are signs worth watching. Apple notes that a non-genuine or unrecognized battery can cause similar symptoms: MagSafe not detected, or charging stuck below 1%.

Wired charging works but wireless doesn't (or the reverse)

If the iPhone charges normally by cable but not on an induction charger, or the other way around, the diagnosis focuses on different components: the charging connector and the bottom flex cable for wired charging, the internal coils for wireless. A MagSafe accessory that isn't recognized usually points to this second case.

Unexpected restarts or freezes

An iPhone that shows the Apple logo on a loop, freezes, or shuts down without warning deserves a test with different cables and adapters first, before considering a deeper hardware issue.

Taking the diagnosis further

In every case, Apple recommends running its built-in diagnostic suite (Mobile Resource Inspector) before any repair, then physically inspecting the connectors for visible damage. Only after these steps does replacing a specific component (battery, logic board, USB-C connector, or back glass) come into play.