Phone will not charge? The five causes, cheapest first

A phone that will not charge feels like a dead phone, and a dead phone feels like a crisis. It usually is not. Nearly every phone that comes to us “not charging” is one of five things, and the list runs from free to routine. The trick is to work through it in order, because the cheap causes are also the common ones, and because a few minutes with a torch and a toothpick can save you a trip.

First, make the phone show you what it is doing

Before you test anything, plug the phone in and watch it for a minute. There are three different behaviours and they point in different directions.

• Nothing at all. No charging symbol, no light, no buzz. The phone may be completely flat, in which case it can take ten minutes or more on a known-good charger before it shows anything. Leave it plugged in and come back.
• It charges, then stops, then starts. The connection is intermittent: the cable, the plug or the port.
• It charges, but the battery does not last. The charging side is fine. This is a battery.

Keep the behaviour in mind as you go down the list.

1. The cable

The cable is guilty far more often than the phone, and a cable is the cheapest thing on this list. Cables are bent, trodden on, wound tightly and yanked out by the lead a dozen times a day, and the wires inside break long before the outside looks damaged. The plug end wears too, so a cable that works in one device may fail in another with a tighter port.

Test with a cable you know works, ideally one that came with a device or one from a reputable maker. If the phone charges, you have found it. If you do not have a second cable, try the same cable in a different device: if it fails there as well, it is the cable.

2. The plug

The small wall adapter is the next suspect. They fail quietly, they are often counterfeit if they were bought cheaply, and a cheap one can deliver less power than the phone needs, so the phone charges slowly or not at all while the screen is on. Try a different plug, or plug the cable into a laptop’s port instead. Again, if the phone charges, that is your answer.

A phone that shows a message about an unsupported or uncertified accessory is usually telling you about the cable or the plug, not about itself.

3. Lint in the port

This one surprises people every time. A phone lives in a pocket or a bag, and every time the plug goes in it packs a little fluff further into the bottom of the port. Over months it compresses into a felt pad, and the plug no longer goes all the way in. The symptoms are a plug that feels loose, that clicks in but does not seat, or that charges only when pushed or held.

Switch the phone off. Shine a torch into the port. If you can see grey or dark material at the bottom, that is lint. Take a wooden or plastic toothpick, work gently along the bottom of the port, and tease it out in flakes. It often comes out as a surprising amount of compacted fluff. Do not use anything metal, do not use liquid, and do not force it. A careful clean brings a port back for nothing more than a few minutes, and it is one of the most satisfying fixes there is.

If the phone has been near water, or if it shows a liquid warning, leave it unplugged and switched off until the port is properly dry. Heat does not help; time does.

4. The port itself

If the port is clean and a known-good cable still only works at an angle, or works loosely, or has to be held, the port has worn. The contacts inside are small and they take thousands of insertions; eventually they bend or the housing loosens. On most phones the port is soldered to the main board or sits on a small board of its own with the microphone and the speaker. Either way it is a repair rather than a reason to replace the phone, and it is one we do ourselves.

A port replacement does not touch the storage, and the phone comes back as it was.

5. The battery

A battery fault does not usually stop a phone charging. It changes how the phone behaves around charging: the percentage drops from half to nothing in minutes, the phone dies in the cold, it shuts down before the day is out, or it will not wake until it has sat on the charger for a while. Most phones show a battery health figure somewhere in their settings, and a figure that has fallen a long way from new tells the story.

A battery is a routine replacement on most models. The honest caveat is that some phones are glued and sealed tightly, which makes the job more involved, and we tell you which kind yours is before any work. What decides the price is the work, not the part.

The signs that mean stop

Three things take this out of the toothpick category and into “switch it off and get it looked at”:

• Heat while charging. Warm is normal. Hot, especially around the port or at the back, is not.
• A swollen case. The screen lifting at an edge, the back bowing, a gap opening along a seam. That is the battery swelling, and you stop using the phone and do not charge it.
• Water. A phone that went in water and now will not charge should not be plugged in again until it has been checked, because corrosion continues while the phone is powered.

If it is still not charging

Then you have ruled out the free causes, which is useful in itself. Tell us what it is doing: whether it shows nothing, charges intermittently or charges but dies, and what you have already tried. We will tell you what it sounds like before anyone travels, and when we have the phone in front of us we work through the charger, the port, the battery and the start-up in that order, because it is far more often one of those than a truly dead board. We will not write a phone off until we have proved it.