The most common mistake with a phone that will not charge is assuming the phone is broken. Far more often the problem is the cheapest part of the setup: a frayed cable, a weak plug, or a wad of pocket fluff packed into the charging port. Work from the outside in, starting with the wall socket and ending with the battery, and you will usually find the culprit in under fifteen minutes without paying anyone.
Below is that order, with the exact checks Apple and Google recommend, the settings that make a healthy phone look as if it has stopped charging, and the signs that really do mean a repair.
First, is it “not charging” or “charging slowly”?
These have different causes, so it is worth a moment to tell them apart.
| What you see | Most likely causes |
|---|---|
| No charging symbol at all when plugged in | Cable, plug, socket, or blocked port |
| Charging symbol, but the percentage barely moves | Weak plug, worn cable, heat, or a phone in heavy use |
| Stops at 80% and sits there | A battery-care setting doing its job |
| A warning about liquid or the accessory | Moisture in the port, or a faulty or unsupported cable |
Step 1: rule out the socket and the plug (two minutes)
Google’s Pixel charging help page starts exactly here, and the advice works for any phone.
- Plug a lamp into the same wall socket. If the lamp stays off, the problem is the socket or the extension lead.
- Avoid charging from a laptop USB port or a car socket while you test. Those are often slower and less predictable.
- Try your charger with another phone or tablet. If that device will not charge either, you have found the faulty part.
Is your plug powerful enough?
Older 5-watt cube chargers still turn up in kitchen drawers. Google’s page says Pixel phones charge best with a 30-watt or higher USB-C PD (Power Delivery) adapter, and that USB-C PD adapters of 15 watts or more will still work. If the label on your plug says 5W or 1A, that alone can explain painfully slow charging on a modern phone.
Step 2: swap the cable
Cables fail where they bend, near each end. Run your fingers along the first few centimetres: any kinks, exposed wire or a loose, wobbly fit is a sign.
Use a different cable that you know works. On a Pixel, Google says a “Check charging accessory” message means the cable or adapter may be damaged or unsupported, which can cause very slow charging or none at all. iPhones show a similar alert for accessories that are not supported.
If you are buying a replacement, get one from the phone maker or a well-known brand. Very cheap cables are a common source of this exact problem.
Step 3: check the charging port for fluff
Pockets and handbags pack lint into the port a little at a time. Eventually the plug cannot push all the way in, so it makes partial contact or none at all. A tell-tale sign: the cable used to click in firmly and now feels loose or stops short.
Turn the phone off and shine a torch into the port. If you can see grey fluff:
- Use a wooden toothpick or a soft, dry toothbrush and work gently along the edges, not down onto the pins in the centre.
- Never use a metal pin or paper clip. You can short or bend the contacts.
- Do not blow into it. Breath carries moisture.
Apple specifically warns against pushing cotton buds or paper towels into the port, and against compressed air, in its advice on wet connectors. If the fluff is packed solid and will not shift, a phone shop can clean it for a small fee, which is still far cheaper than a new battery.
Step 4: did it get wet?
iPhones can detect liquid in the port and will block wired charging to protect the pins from corrosion. According to Apple’s liquid-detection page, you should:
- Unplug the cable from the phone and from the plug.
- Tap the phone gently against your hand with the port facing down.
- Leave it somewhere dry with air moving around it, and wait at least 30 minutes before trying again.
- If the warning returns, allow up to 24 hours to dry fully.
Do not put the phone in rice. Apple says rice particles can damage it. Do not use a hair dryer or a radiator either. Our guide to what to do if your phone gets wet covers the whole drying process.
Step 5: the settings that make it look broken
Sometimes the phone is fine and a feature designed to protect the battery is simply working.
Stuck at 80% on an iPhone
Apple’s charging page explains that iPhone 15 and later models can have a charge limit set anywhere from 80% to 100%. Check Settings > Battery > Charging. If the limit is 80%, the phone stops there on purpose. On iPhone 14 and earlier, Optimised Battery Charging (Optimized on US-English phones) in Settings > Battery > Battery Health & Charging can hold the charge at 80% overnight and finish just before you usually unplug.
Too hot to charge quickly
Phones slow down or pause charging when they get hot. Gaming, video calls or sat-nav while charging, a thick case, or a sunny windowsill all do it. Let the phone cool, take it out of its case and charge it on a hard surface, not a duvet. Our explainer on why phones get hot covers the warning signs.
Use the built-in check on a Pixel
On Pixel 6 and later, Google lists Settings > Battery & charging > Charging diagnostics. It looks for heat, liquid, debris and incompatible chargers, and tells you what it found.
Step 6: if it still will not charge, try this before booking a repair
- Plug in with a cable and plug you have proved work, then leave the phone alone for at least 10 to 15 minutes. A completely flat battery can take a while before the screen shows anything. Google’s page suggests a similar wait.
- Force a restart. On a Pixel, Google says to hold the power button for about 35 seconds. iPhones have their own button sequence, which varies by model; Apple’s support site lists it.
- Try wireless charging if your phone supports it. If wireless works and wired does not, the fault is almost certainly the port.
When it really is the battery
Batteries wear out. Every phone battery holds a little less charge each year, and eventually a worn battery can struggle to charge properly or drop from 30% to nothing without warning. If you want to understand what “capacity” figures mean for lithium batteries in general, this explanation of what a capacity percentage after hundreds of charge cycles means uses the same battery chemistry and is clearly written.
Signs it is time for a repair rather than another cable:
- The phone charges but drains very fast, even after ruling out apps draining it overnight.
- It switches off at 20% or 30% left.
- The back or screen is lifting or bulging. Stop charging it straight away and take it to a repairer. A swollen battery is a fire risk.
- Nothing above has worked, with two different known-good cables and plugs.
Before any repair, back the phone up if you can still switch it on. Repairs and resets can wipe data.
Frequently Asked Questions
Why does my phone charge with one cable but not another?
The cable that fails is almost certainly damaged inside, usually near one end where it bends most, or it is a cheap cable that cannot carry enough power. Bin it and use cables from the phone maker or a reputable brand. Phones also refuse some accessories they do not recognise.
Is it safe to charge my phone overnight?
Modern phones stop charging when full and have settings to reduce battery wear, such as Apple’s charge limit and Optimised Battery Charging. Charge on a hard surface, not under a pillow, and use a decent plug and cable. If the phone ever feels very hot or looks swollen, unplug it and get it checked.
Can I use my laptop to charge my phone?
Yes, but it is usually slower than a wall plug, and some laptop ports give very little power, especially when the laptop is asleep. For a quick test of whether the phone charges at all, a wall socket with a known-good plug is more reliable.
How much does a phone battery replacement cost?
It varies a lot by phone model, age and repairer, so check the manufacturer’s official repair page for your exact model. Get a quote before agreeing to any work, and ask whether a cleaned port or new cable has been tried first.
Last updated: November 15, 2026