Why a new battery can breathe new life to an old iPhones

Apple has published a letter explaining the confusion caused by the iOS 10.2.1 update last year that prioritized battery health over peak performance. The company is also offering deep discounts on battery replacements, down from $79 to $29, and will issue a software update that provides far more insight for customers into the state of their battery health.

December 30, 2017: Forget mid–January, Apple starting discounted battery replacements now.

"We expected to need more time to be ready," an Apple spokesperson told iMore. "But we are happy to offer our customers the lower pricing right away. Initial supplies of some replacement batteries may be limited."

What you need to know about Apple's $29 battery replacement program


From Apple:

We've been hearing feedback from our customers about the way we handle performance for iPhones with older batteries and how we have communicated that process. We know that some of you feel Apple has let you down. We apologize. There's been a lot of misunderstanding about this issue, so we would like to clarify and let you know about some changes we're making.

First and foremost, we have never — and would never — do anything to intentionally shorten the life of any Apple product, or degrade the user experience to drive customer upgrades. Our goal has always been to create products that our customers love, and making iPhones last as long as possible is an important part of that.

Specifically, here's what Apple's doing:

To address our customers' concerns, to recognize their loyalty and to regain the trust of anyone who may have doubted Apple's intentions, we've decided to take the following steps:

  • Apple is reducing the price of an out-of-warranty iPhone battery replacement by $50 — from $79 to $29 — for anyone with an iPhone 6 or later whose battery needs to be replaced, starting in late January and available worldwide through December 2018. Details will be provided soon on apple.com.
  • Early in 2018, we will issue an iOS software update with new features that give users more visibility into the health of their iPhone's battery, so they can see for themselves if its condition is affecting performance.

As always, our team is working on ways to make the user experience even better, including improving how we manage performance and avoid unexpected shutdowns as batteries age. At Apple, our customers' trust means everything to us. We will never stop working to earn and maintain it. We are able to do the work we love only because of your faith and support — and we will never forget that or take it for granted.

Simultaneously, Apple has published a tech support article that explains in far greater detail what happens with lithium-ion batteries in modern devices like iPhone.

From Apple Support:

Our intention for iPhone is to deliver an experience that is simple and easy to use. Doing so requires a lot of engineering and many advanced technologies. One important technology area is battery and performance. Batteries are a complex technology, and there are a number of variables that contribute to battery performance and related iPhone performance. All rechargeable batteries are consumables and have a limited lifespan—eventually their capacity and performance decline so that they need to be serviced or recycled. As this happens, it can contribute to changes in iPhone performance. We created this information for those who would like to learn more.

Overall, this is the right move from Apple after a series of missteps: It offers clarity on the issue, communication on why it happened, and explanation of how the company will fix it.

We're still digging into everything, and will update again with more information and further analysis ASAP.

The Genesis of "#iPhoneSlow"

How did #iPhoneSlow become an issue? It starts with a simple problem: Aging lithium-ion batteries. It's been two years since iPhone 6s shipped, and three years since iPhone 6.

Two to three years can be a long time for batteries, as we've seen from these Reddit comments:

My iPhone 6S has been very slow these past few weeks, and even after updating multiple times, it was still slow. Couldn't figure out why, but just thought that iOS 11 was still awful to me. Then I used my brother's iPhone 6 Plus and his was... faster than mine? This is when I knew something was wrong. So, I did some research, and decided to replace my battery. Wear level was somewhere around 20% on my old battery. I did a Geekbench score, and found I was getting 1466 Single and 2512 Multi. This did not change wether I had low power mode on or off. After changing my battery, I did another test to check if it was just a placebo. Nope. 2526 Single and 4456 Multi. From what I can tell, Apple slows down phones when their battery gets too low, so you can still have a full days charge.

Once upon a time, you loaded a web page or downloaded an email then spent a few minutes reading, turned off your iPhone, and went back to your day. Now, we have social and gaming apps that keep the screen on while checking GPS, downloading media, showing the camera's live view, and layering on augmented reality near-constantly. The tech industry has been prioritizing power efficiency over performance for years: Processors could always run at redline, but they'd burn the battery out just as fast.

Balancing power and performance is key, and Apple has been addressing this in multiple ways — like systems-on-a-chip with both high-efficiency and high-performance cores, and machine-learning-based power management.

But lithium-ion batteries are lithium-ion batteries. When it comes to older phones or those with poor battery health, Apple begun prioritizing battery life over processor speed in iOS 10.2.1. Here's what Apple told me at the time:

"With iOS 10.2.1, Apple made improvements to reduce occurrences of unexpected shutdowns that a small number of users were experiencing with their iPhone," Apple told iMore. "iOS 10.2.1 already has over 50% of active iOS devices upgraded and the diagnostic data we've received from upgraders shows that for this small percentage of users experiencing the issue, we're seeing a more than 80% reduction in iPhone 6s and over 70% reduction on iPhone 6 of devices unexpectedly shutting down.

"We also added the ability for the phone to restart without needing to connect to power, if a user still encounters an unexpected shutdown. It is important to note that these unexpected shutdowns are not a safety issue, but we understand it can be an inconvenience and wanted to fix the issue as quickly as possible. If a customer has any issues with their device they can contact AppleCare."

That caused a hit to the phone's performance, but now allowed older iPhone models to last longer throughout the day and keep them from unexpected shutdowns. Here's what I wrote at the time:

My understanding is that, if a particularly processor-intensive task, such as a complex photo filter, caused a significant spike in power demand, an older battery unable to meet that demand could prompt a shutdown. So, by improving the advanced battery management in iOS 10.2.1, Apple has reduced the likelihood of that happening.

Batteries do age with time and charge cycles, though. To help with awareness, Apple is adding a service notice to Settings > Battery in iOS 10.2.1. It's similar to the one already in place on the Mac. Anyone with a particularly weak battery who still experiences the issue should contact AppleCare.

But Apple's power management may have been too overly aggressive (or the "battery service" notice in Settings was overly passive). Between Reddit threads and Geekbench tests, a number of users experienced Apple's ramped-up power management without seeing the explanation or understanding why.

After complaints, Apple initially provided iMore with the following statement:

"Our goal is to deliver the best experience for customers, which includes overall performance and prolonging the life of their devices. Lithium-ion batteries become less capable of supplying peak current demands when in cold conditions, have a low battery charge or as they age over time, which can result in the device unexpectedly shutting down to protect its electronic components.

Last year we released a feature for iPhone 6, iPhone 6s and iPhone SE to smooth out the instantaneous peaks only when needed to prevent the device from unexpectedly shutting down during these conditions. We've now extended that feature to iPhone 7 with iOS 11.2, and plan to add support for other products in the future."

The company has now put a firmer hand on things, rolling out a low-cost battery replacement program and apologizing for the issue. It's in Apple's best interests to keep customers happy so that they remain customers. Likewise, everyone at Apple has friends and family with older iPhones, and I've never gotten anything from anyone there other than a profound desire to keep those iPhones running as well as possible for as long as possible.

Apple would certainly be accused of maleficence either way: If it doesn't provide updates, it's withholding features. If it does, it's overloading. If it prioritizes performance, it's letting old phones die. If it prioritizes battery life, it's slowing them down. It's Apple's job to provide the best balance it can for as many customers as it can, though, and to take any all accusations that come along with it.

Updated December 28, 2017: Updated with a statement from Apple to iMore.

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