Why is my device charging so slowly?

Charging is a negotiation. The charger advertises what it can provide, the device asks for what it wants, the cable has to be able to carry it, and the device's own management will reduce the rate if the battery is hot, very full, or very cold. Any one of those four can cap the whole thing, which is why the same phone charges at very different rates around the house with no fault anywhere.

Step by step

1. Swap the cable first.It is the most common cause by a wide margin, and it takes ten seconds. Many cables are built for low power only, and a cable that has been bent at the plug for a year may have partially failed without looking damaged.
2. Check the charger's rating against the device's needs.The wattage is printed on the charger, in small text on the body. A charger rated well below what the device can accept will charge it correctly but slowly. Charging a laptop from a phone charger is the extreme case of this.
3. Stop charging from a computer or a low-power socket.A USB socket on a computer, a keyboard, a television or a car often supplies a small fraction of what a mains charger does. It will charge, eventually, and sometimes barely faster than the device drains.
4. Look inside the charging port with a light.Pocket lint compacts into the bottom of a charging socket and stops the plug seating fully, which drops the connection to a slow fallback. Clean it gently with a wooden or plastic toothpick, never metal, with the device switched off.
5. Let it cool down.Charging generates heat and the device deliberately slows to protect the cell. A phone charging in a case in direct sun, under a pillow, or while running something demanding will charge slowly by design. Take the case off and move it somewhere cool.
6. Expect the last stretch to be slow.Lithium charging is fast to about eighty per cent and then deliberately tapers. If the first eighty per cent is quick and the rest crawls, that is correct behaviour and not a fault.
7. Check for a battery protection setting.Optimised charging and charge limits hold the device at eighty per cent until it predicts you need it. That looks exactly like a charging fault to anyone who has not turned the setting on themselves.
8. Stop using it while it charges, as a test.Video calls, games, navigation and streaming can consume nearly as much as a modest charger supplies. If it charges properly while idle, nothing is broken.
9. Only then suspect the battery or the port hardware.If a known-good charger and cable, a clean port, a cool device and no protection setting still give slow charging, then the battery or the charging circuit is a fair suspicion — and that is a repair, not a setting.

Tips

• Charging from a wall socket is faster than any USB socket on another device, almost without exception. If speed matters, use the mains.
• A cheap charger that delivers less than it claims is common. If a charger is unbranded and unrated, it is worth testing against a known good one before concluding the device is at fault.
• Wireless charging is slower than cable and produces more heat, which then slows it further. It is a convenience rather than a speed.

Common mistakes

• Blaming the device before testing the cable — Cables fail far more often than devices, and the test is free. Almost every slow-charging complaint should start here.
• Poking a charging port with a pin or a paperclip — The contacts are delicate and metal bridges them. A wooden toothpick with the device off is the safe way to lift lint out.

If it doesn't work

Questions people ask