1. Try another cable and charger
Cables fail far more often than phones. Use a cable and power adapter you know work with another phone, plugged into a different power point. Look for fraying near the plug, bent or dirty contacts, and plugs that feel loose.
Cheap or damaged chargers can also charge slowly or stop and start. A charger from the phone's maker, or a reputable brand made to the right standard (USB-C Power Delivery for most recent phones), rules this out.
2. Look into the port with a torch
Shine a torch into the charging port. Lint from pockets and bags gets pushed in every time you plug in, and over months it packs into a hard layer at the bottom. Then the plug can't go all the way in, so it only charges at an angle, keeps disconnecting, or doesn't charge at all.
If the plug doesn't click in as firmly as it used to, this is the first suspect.
3. Don't dig with metal
It's tempting to scrape the lint out with a pin or a paperclip. Don't: the pins inside the port are delicate, and metal can short them or bend them. Apple's advice for its ports is the same: don't insert foreign objects. A repair shop can clean a port safely with the right tools, and if lint was the only problem, the phone charges normally straight away.
4. Check for a liquid warning
iPhones and Galaxy phones stop charging through the port when they detect moisture, and show an alert ("Liquid Detected" or "Moisture detected"). Unplug, let the phone dry with the port facing down for a few hours (Apple says at least 30 minutes, and up to a day to dry fully), and try again. Don't override the alert to force charging: charging a wet port is how it corrodes. If the phone has actually been in water, read what to do when a phone gets wet.
If the alert keeps appearing when the phone hasn't been near water, the port or the cable may be corroded or damaged.
5. Is it too hot (or too cold)?
Phones pause charging when they're too hot or too cold, to protect the battery. On an iPhone you'll see Charging On Hold. Take it out of the sun and out of a thick case, let it cool down, and charging resumes by itself. In a Brisbane summer, a phone charging on a car dashboard often hits this.
6. Is it a setting?
Some features stop charging on purpose:
- Optimised Battery Charging on iPhone holds the charge at 80% until shortly before you usually unplug.
- An 80% charge limit on iPhone 15 and later, or battery protection on Galaxy phones, stops at 80% or 85% every time.
If your phone always stops at the same percentage, check these settings before anything else.
7. Restart it
A software glitch can stop a phone recognising a charger. Restart it, or force-restart it if it's frozen (here's how to force-restart iPhone, Samsung and Pixel). Install any software updates once it's charged.
8. Try wireless charging (if your phone supports it)
This is the best test of all:
- Charges wirelessly, but not with a cable: the charging port is faulty (or full of lint).
- Won't charge either way: the battery may be at the end of its life, or there's a fault on the board.
- Charges, but drains fast: the battery is worn (check battery health on iPhone or on Samsung and Oppo).
When it's the port
Charging ports wear out: the contacts lose their spring, pins bend, or corrosion builds up after moisture. The signs are a loose plug, charging only at an angle, slow or on-and-off charging, and accessories (like wired headphones or a car cable) not being recognised. Replacing the port fixes all of these. On many phones, the port is on a small board of its own that's replaced as one part.
Sources
- Apple Support: If you see a liquid-detection alert on your iPhone
- Apple Support: If your iPhone or iPad gets too hot or too cold
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