The iPhone features remarkable battery life, however, not every user experiences peak performance. It is essential to calibrate the lithium-ion battery periodically. This article details the process for maintaining your iPhone’s battery, which will ensure more accurate battery metering. This method also applies to the iPad and iPod Touch, as well as most other devices with lithium-ion “smart” batteries.
Lithium-ion batteries degrade as they age and undergo repeated charging and discharging cycles. Operating systems, such as iOS, track the battery’s operating range. Regardless of wear and age, battery tracking requires occasional adjustment. Battery calibration helps iOS re-calculate the range of battery life. One should calibrate the battery periodically (every 1 – 3 months) and after every major iOS update. If you upgrade iOS and notice diminished battery life, inaccurate battery metering or unexpected shutdowns, try calibrating the battery before anything else.
Battery University, an online authority on batteries of all types, recommends calibrating smart batteries:
The chemical battery representing the actual energy storage remains the master while the digital battery provides peripheral support by relying on the information obtained from charge and discharge cycles. But like all fine machines, precise settings begin to shift and need adjustment. The same happens with an SMBus battery that also require periodic calibration. The instructions for an Apple iPad reads: “For proper reporting of SoC, be sure to go through at least one full charge/discharge cycle per month.
It’s important not to confuse calibration with regular charging practices. Your iPhone’s battery will last longer if you charge your device often, before it gets down to 0%. Ideally, you should plug your device into a charger before it goes below 20%. These are ideals and not practical for most people. In real life, many people need a full day’s charge. With battery replacements from Apple as low as $49, it’s an easier solution than closely-managed charging. For those who love fiddling and want to keep their battery in optimal condition, please read “How To Extend iPhone Battery Lifespan”.
With every iOS update, new features are added, some of which affect battery life. Apple’s engineers often improve some aspects of battery life, while also introducing battery-intensive features, such as background updates. Allowing the battery to fully drain and recharge calibrates iOS to detect the full range of battery life. Some people are skeptical of this theory, and since few know the inner workings of iOS, it may sound superstitious. Research and experience have proven otherwise.
How To Calibrate the iPhone Battery
The first step is to drain the battery completely. This should be accomplished with normal use, but sometimes this may not be an option. After all, you don’t want to head off to work with 2% battery life left. Sometimes that 2% can last a few hours. It’s best to drain the battery when you can do without your device for several hours, perhaps before bedtime. If you still have a little charge left and it’s almost time to sleep, you can drain the battery more aggressively. To expedite battery drainage, turn on the flashlight, turn up the brightness, and play a video, preferably streaming over the Internet.
Once your device powers off due to insufficient battery charge, it’s best to leave it for some time. If possible, leave it overnight and don’t charge it until the following morning. This is not always an option, and if it’s too inconvenient, skip this step. Allowing the device to sit overnight will further drain the battery. You may notice that even when your iPhone runs out of juice and powers down, when you immediately plug it back in, you will see it at 2-3% charge. This is partly due to the fact that some battery life was remaining when it powered down. To keep your data safe, iOS has to power down before the battery is fully drained. Otherwise, it would shut off without being able to save its state to secondary storage.
Next, plug your iPhone into the charger. Keep it in the charger until it’s at least 100% charged. If possible, keep it in the charger longer. According to Apple, 100% means that you will get the expected battery life, but the device can charge beyond this.
So, here’s how things work: Apple does in fact display the iPad (and iPhone and iPod Touch) as 100 percent charged just before a device reaches a completely charged state. At that point, it will continue charging to 100 percent, then discharge a bit and charge back up to 100 percent, repeating that process until the device is unplugged.
Doing so allows devices to maintain an optimum charge, Apple VP Michael Tchao told AllThingsD today.
“That circuitry is designed so you can keep your device plugged in as long as you would like,” Tchao said. “It’s a great feature that’s always been in iOS.”
Keeping the device in the charger after it reaches 100% will ensure it is fully charged. Two additional hours should do it.
It is best to charge your iPhone when it is off. After you plug in the charger, your iPhone will automatically start up in a few minutes. When it is back online, simply hold down the sleep/wake button and slide your finger over the off switch. Your iPhone will charge faster when it is off. It will also generate less heat, which will extend overall battery life.
If you turn your iPhone off to charge, make sure to estimate how long it will take to charge beyond 100%. Three hours is a safe bet for an iPhone 11. My iPhone 6 will charge to 100% in three hours, but the extra two hours ensures that it is fully charged — beyond 100%.
Now that your device is fully charged, you should reset it. This is done by holding down the sleep/wake button (on the top of the device) and home button, until the Apple logo appears. If you have a newer iPhone, without a physical Home button, hold the volume up and sleep/wake button. Your device will boot up and is now reset. Remove the charging cable when your device is up and running.
Step By Step Battery Calibration
The following process is what I consider to be the gold standard of iPhone battery calibration. For some, it might not be possible to follow all of these steps. If you are an on-call professional or hopelessly addicted to your iPhone, you might not be able to turn off your iPhone overnight or even for a few hours. At the bare minimum, you need to drain the battery until the device shuts off, charge your iPhone to 100%, and reset it by holding down the sleep/wake and home buttons until you see the Apple logo.
1. Use your iPhone until it shuts off automatically. If it is near 0% battery life and you want to drain it faster, turn on the flashlight, turn up screen brightness all the way and play a video, preferably streaming from the Internet.
2. Let your iPhone sit overnight to drain the battery further.
3. Plug your iPhone in and wait for it to power up. Make sure to use the charger supplied by Apple or one that runs at the same wattage and amperage.
4. Hold down the sleep/wake button and swipe “slide to power off”.
5. Let your iPhone charge for at least 3 hours. Older iPhones should be charged for 5 hours. The charge progress indicator is not displayed while your iPhone is turned off.
6. With the charging cable still connected, press the sleep/wake button for about a second to start up your iPhone.
7. When the iPhone has booted up, hold down the sleep/wake and home buttons until you see the Apple logo. If you have a newer iPhone, without a physical Home button, hold the volume up and sleep/wake button.