Software · guide

How to fix phone not charging, and the 80 per cent case

By Alberto Gulotta · Updated · 11 min read

How to fix phone not charging has two answers, and the first thing to establish is which one you need. Apple separates them on its own page.

Apple gives this its own section, separate from the fault list
“If your device stopped charging at 80 percent” — three published reasons, none of them a fault:
  • Optimized Battery Charging. It exists “to slow the rate of battery aging by reducing the time that your iPhone spends fully charged”, uses on-device machine learning to learn your routine, and is “active only when your iPhone predicts that it will be connected to a charger for a long period of time”.
  • Heat. “If the battery gets too warm, software might limit charging above 80 percent. Your iPhone will charge again when the temperature drops.”
  • Charge Limit. On “iPhone 15 models and later, you might have a charge limit, which stops your iPhone from charging past a set limit”.

An iPhone that sits at eighty per cent all night is not on Apple’s list of repairs, and two of the three reasons can clear on their own. For a Pixel that “stops charging at a certain percentage”, Google’s steps, under “Troubleshoot slow charging or battery not charging to full”, turn off Charging optimization and then “Try to charge again.”

So before anything else: if the number is moving but stops at eighty on an iPhone, none of the repair steps below apply. Optimized Battery Charging finishes the job when it expects you to want the phone; for heat, Apple says to try “moving your iPhone and charger to a cooler location”; and a charge limit is a setting, which Apple says to change if you want the phone to charge past 80 per cent.

The rest of this page is for the other case, where the number does not move at all.

If it genuinely will not charge — Apple’s order

Eight steps, and two of them are waiting.

  1. Plug into a computer, a power accessory, or a wall outlet.
  2. Restart the phone.
  3. Check the cable and adapter “for signs of damage, like breakage or bent prongs. Don’t use damaged accessories.”
  4. Use a wall outlet, check every connection is firm, or try a different outlet.
  5. “Remove any debris from the charging port”, then plug the cable in firmly.
  6. “Let your device charge for half an hour.”
  7. Still nothing, or a battery icon on screen? Force restart — the buttons differ by model.
    iPhone 8 or later and iPhone SE (2nd generation and later): volume up, volume down, then hold the side button until the Apple logo. iPhone 7: side and volume down together. iPhone 6s or earlier and iPhone SE (1st generation): side (or top) and Home together.
  8. “Let your device charge for another half hour.” Then, if nothing, service.
The step that is not really a step

Apple says half an hour, twice — once before the force restart and once after. Google’s 10-minute step starts with plugging in and waiting one minute, and adds the tell: “If you see a battery icon, your phone is powered off and is charging.” It also warns that “A device with a very low charge will charge for several minutes before allowing the screen to power on.” If no battery icon appears, Google’s page has a separate check for the screen: “there could be a problem with your screen”.

Google’s version adds two tests Apple’s does not, and both cost nothing.

Google’s swap test

pixel

“Try to charge another device with your power adapter and cable.” One move, and nothing to buy to find out.

Google’s outlet test

pixel

“Plug the charger into a wall outlet. Plug in something else, like a lamp.” The same logic one step further back, and just as cheap.

Those two are worth doing early rather than late. A cable, an adapter and an outlet are three suspects, and each can be tested by putting something else on the end of it. The alternative — buying a new cable to find out whether the old one was the problem — is the more expensive experiment.

Two things to take off, and one message to read. Under “Troubleshoot case, battery charger, cable & outlet”, Google starts with the phone case: remove it “to ensure that it doesn’t interfere with your charging plug or wireless charger” — and adds another check: that no accessories, “like cases or battery packs, cover the sensors on your phone or press its buttons”. And if a “Check charging accessory” notification appears, Google says the cable or adapter “may be damaged or not supported by your phone. This can cause your phone to charge very slowly or not at all”.

One more thing from Google’s page: the adapter. For “the best battery experience and charging speeds” it names “A Google 30 W USB-C power adapter or other programmable power supply (PPS) power adapter rated for 30 W or more” and “Other USB power delivery (PD) adapters rated for 15 W or more” — and notes that actual speeds vary by model.

A drawn table of the power adapters Google names for a Pixel and the speed caveat attached
Google’s own list of adapters. That it names nothing below 15 W is our reading of the list, not a quotation. Figure drawn by AI Tools Primer.

What this page will not do is tell you the battery needs replacing. Neither vendor’s procedure reaches that conclusion; both end at service, which is where somebody can measure it.

It also will not tell you to clean a charging port with a pin, a paperclip, or anything else. Apple says to remove debris and does not say with what.

And it will not treat a phone that stops at eighty per cent as broken; on an iPhone, Apple does not.

Where to start

Three ways in. If it stops at eighty per cent, take the first.

“It stops at eighty per cent.”
On an iPhone, not a fault — the 80 per cent case
“Nothing happens at all.”
Two waits and a force restart — when it really will not
“Is it the cable or the phone?”
Two tests that cost nothing — the swap tests

A touch screen, liquid detection, the orange dot, Mac charging, storage and SOS.

A screen that ignores youFour steps from Apple, and one of them ends by telling you to change your charger.Open this guide → Liquid detected on iPhoneWhat Apple says to do, the timings, and the three things not to.Open this guide → The orange dot on iPhoneA report rather than a fault — and the green one tells you less than it looks.Open this guide → Is the Mac actually chargingAmber means two opposite things, USB-C has no light at all, and the menu has four answers.Open this guide → Freeing up space on iPhoneWhere the space actually went, and the setting that keeps it from filling again.Open this guide → Turning off SOS on iPhoneAnother state that looks like a fault and is a mode.Open this guide →

Buttons, restarts and sound

Force restarting, turning a phone off, and a speaker with no sound.

Force restarting an iPhoneThe button sequence by model, and what it does not erase.Open this guide → Turning a phone offThe button changed meaning, and the old instruction now opens something else.Open this guide → A phone speaker with no soundTwo published tests — and the settings that silence a working speaker.Open this guide →

Other things that stop working

A keyboard, one AirPod, and a drive’s health.

A keyboard that will not typeWindows has a setting whose documented job is to ignore what you type.Open this guide → One AirPod with no soundApple calls it two problems with two procedures — and one ends at a slider on the phone.Open this guide → Checking a drive’s healthMicrosoft has removed WMIC from supported versions of Windows 11; Get-PhysicalDisk, a PowerShell cmdlet, has a HealthStatus column.Open this guide →

Not covered here. It will not tell you the battery needs replacing. Neither vendor’s procedure reaches that conclusion; both end at service, where somebody can measure it.

It will not tell you what to clean a charging port with. Apple says to remove debris and names no tool.

And it will not treat a phone that stops at eighty per cent as broken. What holds instead is simple: the eighty per cent case is explained as the maker explains it, and nothing here asks you to replace a battery.

Sources

  1. Apple, If your iPhone or iPod touch won’t charge — Apple Support (the ordered steps of plugging into a computer, power accessory or wall power outlet, restarting the device, checking the charging cable and USB adapter for signs of damage such as breakage or bent prongs with the instruction not to use damaged accessories, using a wall power outlet and checking for firm connections or trying a different outlet, removing any debris from the charging port and firmly plugging in the cable, letting the device charge for half an hour, force restarting with the model-specific sequences for iPhone 8 or later and iPhone SE second generation and later, for iPhone 7 and iPod touch seventh generation, and for iPhone 6s or earlier, iPhone SE first generation and iPod touch sixth generation or earlier, then letting the device charge for another half hour before seeking service; and the separate section on a device that stopped charging at 80 percent, covering Optimized Battery Charging in iOS 13 and later and its purpose of slowing battery aging by reducing the time spent fully charged, its use of on-device machine learning and its activation only when a long connection is predicted, the software limit on charging above 80 percent when the battery gets too warm with charging resuming when the temperature drops, and the advice to move the iPhone and charger to a cooler location; and the charge limit available on iPhone 15 models and later, with the advice to change it to charge past 80 percent) — support.apple.com, read 22 August and 28 September 2026.
  2. Google, Fix a Pixel phone that won’t charge or turn on — Pixel Phone Help (the recommendation of a Google 30 W USB-C power adapter or other programmable power supply adapter rated 30 W or more, or other USB power delivery adapters rated 15 W or more, with the note that actual charging speeds vary by model; the instruction to press and hold the Power button for 5–7 seconds; the instruction to remove the phone case so that it does not interfere with the charging plug or wireless charger; the checks of trying to charge another device with the same power adapter and cable, confirming the cable is securely connected at both ends, checking that nothing such as dust or lint is in the port, and trying another cable or power adapter; the tip that a “Check charging accessory” notification indicates a cable or USB power adapter that may be damaged or unsupported and that this can cause the phone to charge very slowly or not at all; the outlet check of plugging the charger into a wall outlet and plugging in something else such as a lamp; the check that no accessories such as cases or battery packs cover the sensors or press the buttons; the instruction to charge for 10 minutes, wait one minute, and take a battery icon as an indication that the phone is powered off and charging, with the note that a device with a very low charge charges for several minutes before the screen powers on; the screen check when no battery icon appears; and, for a phone that stops charging at a certain percentage, the steps to turn off Charging optimization and try to charge again) — support.google.com, read 22 August and 28 September 2026.

Written by Alberto Gulotta

Founder and editor of AI Tools Primer, writing from Palermo, Italy. Thirty-five years of taking computers apart, starting with a Commodore 64 — the long version is on the about page.

Something wrong on this page? Write to aitoolsprimer@gmail.com and it gets fixed.

Written on 22 August 2026 · last checked 30 September 2026.

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