There is a certain anxiety in knowing your phone is nearly dead. This can only be made worse by adding in the additional complication that your iPhone takes an eternity to charge up. Battery life and charging might seem like a simple thing, but there are many links in the chain and any could be at fault. Luckily, most reasons for slow charging don't even require a toolkit, just a little investigating.
Before undertaking any of the more time consuming solutions below, these are a few fundamentals to get you started.
- Try a different charger. This may be as simple as a bad cable or power brick.
- Restart your iPhone. This can clear up any minor software hiccups.
- Is your phone also getting really hot? Even if it’s not charging? This might be an issue with software.
- If your phone specifically struggles to charge past 80%, check Settings > Battery > Battery Health and Charging to see if Optimized Battery Charging is toggled on. This setting prevents the phone from charging to full capacity. This could prolong the longevity of your battery.
Power Source Wattage Too Low
Ever notice all the text printed on nearly any power adapter in your house? The information here is not just model number and manufacturer specific data, it also includes the specifications of the adapter. The amount of power the charger can output is strongly related to the rate a device can charge.
- On the part of your charger that goes into the wall, look for text. It should contain several important bits of information.
- Input Voltage: This is not specifically important in this case, but it is typically the first item in the string of things you’re looking for. It will likely indicate 100-240V AC.
- Output Voltage and Amperage: These will generally be listed together. The adapter may be capable of outputting multiple voltages including 5V, the typical voltage for USB charging. Higher voltages may be utilized on larger devices, or to support fast charge standards. Each individual voltage should have a correlating Amp rating.
- Wattage: Some manufacturers, like Apple, list this right on the adapter. But if not, you can calculate it yourself! Wattage is simply Volts multiplied by Amps. In the case of a basic Apple iPhone charger, the USB brick is rated for 5V and 1A. Therefore it would be a 5 Watt charger (5x1=5).
- Save yourself some brain cells and use a wattage calculator if your numbers aren’t as easy.
- Be aware the OEM Apple 20W charger comes with a USB C port on it, so you’ll need a USB C to Lightning Cable.
- There are a bevy of reputable non-Apple alternatives, but not all chargers are equal. Look for the "Made for iPhone" branding to point you towards more reliable brands. These need to contain protections in the cable to qualify for this certification. Long term use of substandard chargers can damage the charging mechanism within your phone.
- Apple’s proprietary Lightning Port is based on the decades old USB 2.0 spec. In addition to lackluster data transfer speeds, charging is only supported at 500mA (that’s .5A)! Your computer’s USB port is effectively a 2.5 Watt charger. It’s fine as a desperation move, but be forewarned–you’ll be waiting a while.
Debris in Lightning Port
Think about how many times a day you put your phone in a pocket, or a bag. What else is in that pocket, or that bag? Even if it’s your dedicated phone pocket, that pocket is bound to have lint in it. To lint, the Lightning Port may as well be a giant magnetic crevice. If the speaker and microphone grilles at the bottom of your phone are clogged with dust, chances are your charge port is too.
- Inspect the port using a flashlight. It is common for bits of lint or rubbish to get caught and compress into the back of the port.
- Check the fit of your cable. Does the lightning plug sit flush with the bottom of the phone? It should. If it sits askew, or there’s a gap where you can still see the metal of the charger, a good cleaning is in order.
- This may limit the amount of contact the charger is actually making with the port.
- If your charge port has signs of burn or corrosion, skip ahead to the Faulty Lightning Port section.
- If there is debris in the port, use a toothpick or any other non-conductive probe to clear it. Insert the point straight to the back and gently scrape out residual debris. Be mindful of the pins and pay attention to the corners.
- If a toothpick is too large, try splitting the tip with a knife. Half a toothpick can usually reach the most recessed crevices of a charge port.
Poorly optimized or buggy software can be a battery killer. If the onset of your battery issue is sudden, it may be that an app updated or your phone installed a patch. The newer version could contain features that are more resource intensive, or a bug which unintentionally runs your battery dry. If your phone is consuming a lot of energy, it will appear to be charging slowly because the rate of power consumption is close to the rate of charge. You may also notice that your phone is especially warm in this case.
- Have any apps updated recently? In the App Store, select your profile by tapping your profile avatar in the upper right corner (it will be your initials if you never set an image). Apps in need of update will be shown here under the "Personalized Recommendations" settings. Recently updated apps will be listed beneath those.
- Check battery usage in the battery menu within Settings. Beneath Battery Health and any usage graphs is a breakdown of all apps, or functions consuming energy.
- Quit any app which seems a likely offender and see if it makes a difference to battery life. Uninstall any apps in the overlap (of recently updated and consuming large amounts of battery) which are having a negative impact. If battery life improves, try reinstalling the app.
- A fresh OS install is a drastic measure to address battery life, but could still be helpful, especially if some corruption is contributing to the issue.
- Be sure to have a backup of your device and connect to iTunes to perform the reset for the most reliable results.
Faulty Lightning Port
If you’ve cleaned all the gunk out of the port, or everything looked spotless from the start, the port might just be faulty.
- If your cable seems loose when you connect it or you have to hold it in a certain position, the port itself may have some loose connections.Your best bet here is to replace the charge port assembly.
- Perform a visual inspection of the device’s internals. Look for any sign of damage.
- Faults in the lightning port assembly can often be attributed to liquid entry. Despite water resistance, there are many potential entry points along the bottom of the phone.
- Be sure to source replacement charge port assemblies from reputable vendors or splurge for the higher quality part. Substandard third party replacements are rampant.
Unlike the Alkaline batteries you put in your TV remote, the battery in your iPhone is a little more complex. In addition to the battery cells, where all the energy generating chemistry occurs, the battery also contains a management board. Certain types of failures within this board could cause slow charging.
- Check your battery health. In Settings navigate to the Battery menu. iPhones will have an option here simply called “Battery Health.” Does it say Service? If so, battery replacement is good start.
- Just because this says your battery is performing as expected, it does not guarantee battery reliability. As with most electronic diagnostics, trust a fail, but not a pass.
- If you are not convinced of your battery’s good health, get a second opinion. Coconut Battery has been used by iFixit forum regulars for years to get more battery info. You will need a Mac to run it, but it gives far more detail.
The Tristar chip (or Hydra in the iPhone 8 and newer) on an iPhone logic board is responsible primarily for USB related functions. But it is also integral in the charging process. It detects items connected via the Lightning port and has electrical lines of communication to the charging chip. It is also the chip most commonly damaged on the board.
- Tristar issues manifest in many ways, slow charging is only one of them. You can use a multimeter to easily test some functions of Tristar.
- This repair requires the ability to solder small surface mount components onto a circuit board. Unless this is a skill you are practised at, it's best to leave this one to the professionals. Any good shop that does board level repairs should be able to . Ask around to find a board level specialist in your area. Even shops that don’t work on boards, may be able to point you to someone who does!
- This issue is so common, there are tools designed solely to test the functionality of this chip. They are a bit pricey for one time use, but handy to have if you are a serial fixer.
Faulty Logic Board
The logic board is the hub for the vast majority of an iPhone's functionality. Any number of the small components on the board may have failed or become damaged, and is a safe assumption of cause if nothing else on this page has worked.
- Check for obvious signs of a board issue - burned or cracked components, liquid residue, corrosion or bend. If there are signs of liquid the iPhone Liquid Damage Guide might help.
- Replacing the logic board is often the most practical solution for a DIYer whose board has failed.
- Contrary to popular belief, the board itself can be repaired. However, it requires specialized tools and microsoldering know-how. If you’re feeling curious, and want to know more about getting into micro soldering, here’s some good reading and some good watching to get you started.