Phone charging slowly: causes ranked by likelihood
Slow charging feels like a battery problem, but the battery is near the bottom of the list. Work through these in order of likelihood — the first two solve most cases and cost nothing to test.
1. The cable (most common)
Cheap and worn cables are the number-one cause. A frayed or thin cable can reduce the power your phone negotiates by a large margin, even paired with a fast adapter. Try a different good-quality USB-C cable — if charging speeds up, you found it. Cables over a couple of years old are worth replacing outright.
2. The adapter
Fast charging needs a fast charger. An old 5W plug, a PC USB port, or a car socket will all charge slowly by design. Use a USB-C Power Delivery (PD) adapter rated 18–20W or more (match your phone’s supported wattage). Charging from a laptop or a hub is always slower than a wall charger.
3. A dirty or loose charging port
Pocket lint packs into the port and blocks a solid connection — a surprisingly frequent cause of slow or intermittent charging. Power the phone off and gently clear the port with a dry wooden or plastic toothpick (never metal), then a short burst of compressed air. If the cable feels loose or wobbly in the port, that’s the same problem.
4. Heat
Phones deliberately slow charging when they’re warm, to protect the battery. If the phone is hot — in sunlight, under a pillow, or in a thick case while gaming — it will trickle-charge. Take the case off, move it somewhere cool, and stop using it while it charges.
5. Battery-protection settings
Features like Optimised Battery Charging (iPhone) and Adaptive Charging (Android) intentionally hold charging at 80% overnight and finish just before your alarm. That’s not a fault — it’s protecting the battery. If you need a fast top-up, these can be paused in battery settings.
6. Background load and the screen
Charging while gaming, navigating, or with the screen bright at full brightness means power goes straight back out. Charging with the screen off is always faster.
When it’s the battery (hardware)
If none of the above helps and the phone is three or more years old, the battery has likely aged (check battery health in settings — below ~80% capacity it both drains and charges poorly). A battery replacement is a cheap, worthwhile repair on a phone that still gets security updates — check yours in our support tracker first.
Frequently asked questions
Does charging overnight damage the battery?
Modern phones manage this well, and the optimised-charging features exist specifically to avoid holding at 100% all night. It’s fine, though keeping the battery mostly between 20–80% is gentlest long-term.
Is wireless charging slower?
Usually yes, and misalignment on the pad slows it further or stops it. For speed, use a cable; for convenience, make sure the phone is centred on the pad.
Should I use the charger that came with another device?
A good PD charger from a reputable brand is fine and often better than an old in-box plug. Just make sure it’s rated for enough wattage.