Guide · 6 min read
Phone not charging at all.
Total failure is easier to diagnose than slow charging: there are only four things in the chain — outlet, adapter, cable, port. Change one at a time, never two, and you will find it in ten minutes without buying anything.
Before you swap anything: is it actually dead?
A deeply discharged lithium battery will not show a charging screen immediately. Leave the phone on a known-good wall charger — not a laptop port, not a car socket — for 30 minutes before concluding anything. Then force-restart: on iPhone 8 and later, volume up, volume down, then hold the side button until the Apple logo appears; on Android, hold power for 20–30 seconds.
The isolation table
| Test | What you change | If it now charges |
|---|---|---|
| A | Same brick and cable, different wall outlet | Dead outlet or tripped circuit |
| B | Different adapter, same cable | Adapter has failed |
| C | Different cable, same adapter | Cable has failed (most likely) |
| D | Same adapter and cable, different phone | Your phone's port or board |
| E | Wireless charger instead of the port | Port fault, battery is fine |
Test E is the one people forget and the most informative: Qi charging that works while cables do not means a port fault, not a battery. That is a repair, not a purchase.
The lint check
Compacted pocket lint is the leading cause of a phone that stops charging with no warning and no drop. It packs into a dense pad at the base of the port, so the plug bottoms out on debris instead of contacts — it feels seated but sits a millimetre proud, with no connection at all. Power the phone off, shine a torch down the port, and compare with a port you know is clean. Lift the pad out with a wooden toothpick or plastic pick, working from the sides inward. Never a metal pin or paperclip: the contacts are thin gold plating over copper and a scratch is permanent. Skip compressed air, which pushes moisture and debris further in.
Liquid, accessories, and software blocks
iOS and Android detect moisture on the connector pins and refuse to charge on purpose — "liquid detected in USB-C connector", or a water-drop icon. That protects the pins from corroding under voltage, and overriding it is a bad idea. Unplug, tap the port gently downward against your palm, and leave the phone in dry moving air for at least 30 minutes; a soaked port can take a day. Rice does nothing but add starch dust.
Also check for an "accessory may not be supported" prompt, which points at a damaged cable or a non-compliant adapter rather than the phone. And an OS-level charge cap — iPhone's 80% limit, Samsung's Protect Battery — looks like "stopped charging" once the phone is at the cap.
When it is the adapter
Wall adapters fail two ways: dead outright, or dropped back to 5V because the PD controller has given up. Test B catches the first; the second looks like "charges, but takes all night" and belongs in the slow-charging ladder. If the brick is warm with nothing attached, smells of hot plastic or has a deformed shell, stop using it — the heat guide covers the replace-it signs, the safety guide the marks to insist on next time.
Replacing it: match the wattage your phone draws using the device wattage map, buy a certified unit at that class or above, and pair it with a proper cable from the cable guide. A 30W USB-C brick is the sensible phone default — full speed on any iPhone, headroom for a tablet.
FAQ
My phone shows the charging symbol but the percentage never rises. Why?
The link has fallen back to 5V/0.5A, which is 2.5W — enough to light the icon and not enough to outrun the screen. Swap the cable first, then the adapter, then check the port for debris.
How do I clean lint out of a charging port safely?
Power the phone off and use a wooden toothpick or plastic pick, working from the sides inward — never metal, and no canned air.
The phone says liquid detected and will not charge. What now?
Leave it. The block exists to stop the pins corroding under voltage. Tap the port downward, air-dry for 30 minutes or longer, and use wireless charging meanwhile if you have it.
Wireless charging works but cables do not — what does that mean?
Battery, charging circuit and software are fine; the fault is physical — the USB port or its flex cable, which is a low-cost repair.