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01The 60-second car charger check
When a car charger is not working, the cause is usually something simple: the socket is switched off with the ignition, the plug isn't making contact, or the cable has given up. A blown fuse comes next. A faulty phone is the least likely.
If the charger's light comes on but the phone does nothing, skip straight to the cable and phone section. If the light never comes on in any socket, work through the steps below.
02Is the socket getting power?
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Check how your socket is wired
Some 12V sockets are live all the time; most turn off with the ignition so they can't drain the battery. Your owner's manual says which. Push-button-start cars usually need accessory mode, not just the doors open.
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Look inside the socket
With the car off, shine a light in. Coins, foil gum wrappers and crumbs are common, and a coin across the contacts is exactly what blows the fuse. Remove debris with something non-metal, like a wooden skewer.
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Test with a different plug-in device
A dash cam, tire inflator or another charger tells you instantly whether the socket is dead or your charger is.
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Find the fuse
The manual's fuse chart lists the power outlet or cigar lighter fuse, usually in a panel under the dash or in the engine bay. Pull it with the fuse puller in the box and look at the metal strip. A broken strip means it's blown.
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Replace it with the same rating
Use a new fuse with the exact amp rating printed on the old one (often 15A or 20A for outlets). Never fit a higher rating. If the new fuse blows straight away, something is shorting, and that's a job for a mechanic.
If the plug or socket is too hot to touch, discolored, or smells of burning plastic, unplug it and stop using that socket. A worn socket that makes poor contact heats up under load.
03Light's on, phone isn't charging
Cables fail in cars far more than at home. They get pinched in doors, kinked under seats and baked on the dash. Swap in a cable you know works. If the phone now charges, bin the old one. A USB-C cable that's also flaky at home has its own guide: USB-C cable not charging.
Check the phone side too. Pocket lint packs into charging ports and stops the plug seating fully, which feels like a loose cable. On an iPhone, a "This accessory may not be supported" message often points to a damaged or uncertified cable or charger; see what that alert means.
Finally, the charger plug itself. Cheap units have weak side springs and a center contact that wears down, so they lose contact on every bump. If it only works when you hold it at an angle, replace it.
04Charges, but too slowly to keep up
A phone running maps, music and a bright screen can use power almost as fast as a weak charger supplies it, so the percentage stalls or drops. The port type is usually why.
| Power source | Typical output | Keeps up with navigation? |
|---|---|---|
| Built-in USB-A port (older cars) | Often 5W to 7.5W; some are mainly for data | Rarely |
| Basic USB-A 12V charger | Around 12W | Just about |
| Quick-charge USB-A charger | Up to about 18W on supported phones | Usually |
| USB-C PD 12V charger | 20W to 30W per port on most phones | Yes, with room to spare |
| Wireless car mount | Up to 15W on many models, less with heat | Sometimes, if it stays cool |
Two more culprits: wired CarPlay or Android Auto through a car's USB port, which often supplies only a modest current, and heat. A phone on a windshield mount in summer will throttle charging however strong the charger is. The fix for both is a USB-C PD charger in the 12V socket and a vent mount that gets AC airflow. More in phone overheating in a car mount.
05Picking a replacement that lasts
Dual-port USB-C PD
- Fast-charges iPhone and Android
- Two phones at once
- Small, sits flush
Multi-port family charger
- Four or more devices
- Power is shared between ports
- Look for at least one USB-C port
Charger with built-in cables
- No loose cables to lose or pinch
- Retractable cords wear over time
- Check the connector types match your phones
Pick by how many people charge at once. Check each listing's per-port output against what your phone can take.
Setting up the whole car? Our car charging setup guide covers mounts, cables and chargers together.
Questions people ask
Why does my car charger only work when the engine is running?
Most 12V sockets are wired to switch off with the ignition so they can't drain the battery. Turn the key to accessory or start the car. Your owner's manual will say whether any socket stays live with the car off.
How do I know if my car's charger fuse is blown?
Every socket stays dead, even with a device that works in other cars. Find the power outlet fuse using the manual's fuse chart and pull it. A broken metal strip inside means it's blown. Replace it with the same amp rating.
Why is my phone charging so slowly in the car?
Built-in USB-A ports and basic chargers often supply only 5W to 12W, which navigation and a bright screen can nearly cancel out. A USB-C PD charger in the 12V socket delivers 20W or more. Heat from sun on the phone also slows charging.
Can a car charger damage my phone?
A decent charger won't. The phone only draws what it needs. Very cheap, uncertified chargers can deliver unstable voltage, so avoid no-name units with no safety markings and stop using any charger that gets hot or smells.
Why does my car charger keep cutting in and out?
Usually the plug is loose in the socket or the cable is damaged near a connector. Push and twist the plug in firmly, try another cable, and clean any debris from the socket. If it still cuts out, the charger's contacts are worn.