It wasn’t that long ago—December 2017—that Apple admitted it had been slowing down iPhones over time on purpose. Ostensibly, this was to make sure you didn’t want to throw your phone against a wall after an OS upgrade because the batteries inside were becoming a real drag on performance and sometimes causing unexpected shutdowns. Apple throttled the battery output to the CPU down on older phones so the battery would last a little longer and shutdowns would cease.
The slowdown in performance was discovered when replacing a battery put older iPhones back to full performance. Which would all have been a good thing—if the general public had been told about it upfront.
In response to that kerfuffle, Apple offered $29 replacement batteries for select older iPhone models throughout 2018. However, Apple did not stop throttling older iPhones. The difference is, it’ll actually tell you about it now. And by tell, I mean, you can go looking for the info in your iPhone’s battery settings.
Is your iPhone’s battery capacity bad enough that it needs a replacement? That can be a scary process for your expensive life-line to all connectivity. And it isn’t cheap. It costs $49 for older iPhones or $69 the X, XS, XS Max, and XR, if you go through Apple. Plus you may go without your iPhone for days if you don’t live near an Apple Store. You could also go to a third-party fix-it shop. Or do it yourself—iFixit sells iPhone Battery Kits for $29 (still!) for iPhone 8 Plus back to iPhone 4s.
Before you decide, make sure to dig into the data about your iPhone’s battery to determine if the replacement is even warranted. Rest assured, if you hang onto your iPhone long enough, it will be warranted eventually.
In iOS 11.3, released in March 2018, Apple added Battery Health in order to save face amidst legal battles related to BatteryGate. (Those battles still exist. Apple’s got some weird arguments on why it shouldn’t be held responsible; it’s also is trying to get the class-action suits for fraud tossed because attorneys for the class allegedly quoted confidential documents.)
The reason for the existence of the Battery Health option is to provide the smallest modicum of transparency about the capacity of an iPhone’s battery, and if iOS is crippling iPhone performance. Supposedly, iOS will only throttle the power to the CPU if your battery is below 100 percent capacity and it has one unexpected shutdown.
In iOS 11.3 or later go to Settings > Battery. At the bottom, Apple now includes nice graphs showing your iPhone battery-charge levels and screen activity over the last 24 hours or 10 days.
You can also see the full battery usage per app. That’s a nice way to determine if some app is in the background sucking up all the juice, but mostly it’s about activity time. (You can toggle back and forth between Activity and Battery Usage.)
Above those, tap Battery Health. This is the area of importance. Next to Maximum Capacity is a percentage of how much your battery can currently hold in comparison to when it was brand new. The lower it is, the worse things are for all the lithium-ion inside holding the power.
Peak Performance Capability is the one to watch. It might say “Your battery is currently supporting normal peak performance.” That means it is, as Data used to say on Star Trek, functioning within normal parameters.
However, it might say “This iPhone has experienced an unexpected shutdown because the battery was unable to deliver the necessary peak power. Performance management has been applied to help prevent this from happening again.”
That last bit is a flowery way of saying “we throttled the power to your CPU for your own good.” This could happen (as of iOS 12.1) even to the iPhone X. It’s unlikely to be seen on the newer XS, XS Max, or XR, at least until iOS 13 ships.
Thankfully, the option should be right there for you to disable performance management.
Be aware that if the phone has another unexpected shutdown that iOS blames on the weak battery getting sucked hard by the CPU, it’ll apply performance management throttling all over again.
You may also see a message that says your iPhone battery’s health can’t be determined, or that it is so sufficiently degraded that now is the time for you to replace it. That generally won’t happen until the maximum capacity is lower than 80 percent after 500 complete charge cycles (read more about that in our story about battery myths).
For more details on what’s happening inside the iPhone, download an app like Lirum Device Info Lite. It doesn’t look at battery info specifically, but does an excellent job graphing the ups and downs of your iPhone chip’s performance under This Device > CPU > CPU Actual Clock (vs the CPU Maximum Clock; you want to see the same number for both). You’ll be able to see performance changes in real time.
There used to be third-party tools that helped you look at the wear on your battery, like RBT Digital’s Battery Life, but with the iOS 11.3 update, Apple locked apps out of looking at the battery capacity or charge cycle number. Way to keep it transparent, Cupertino.
If you want to do any of this on your iPad or even the iPod touch—you can’t. Battery Health is only available on iPhones, because Apple isn’t throttling iPads and the iPod touch. However, the charts displaying charge levels and screen activity are available.
If you’re interested in counting exactly how many charge cycles your iPhone (or iPad or iPod touch) have been through, that’s not easy to find but there are desktop apps that can help. CoconutBattery 3 for macOS or the $35 iBackupBot for Windows can pull data from an iDevice connected to a PC and display the “cycle count” number, among other data. At anything over 500 charges, your iPhone battery has seen better days; for iPad the number is more like 1,000 cycles (it has a bigger battery).
So what’s the criteria for getting a new battery? Certainly, consider it if you see the performance management kick in too often. Also if you see the Lirum Device Info app showing significant downgrade in the CPU Actual Clock number. Definitely upgrade if the Peak Performance Capability says your battery health is “significantly degraded.”
If you’re brave and/or cheap, get the iFixit battery replacement kit option. If you’re not brave (and who would blame you), have the money, or have an iPhone X (iFixit doesn’t have a battery kit for the X), have the pros do it. Hopefully you’re near an Apple Store or you may have to send off the iPhone for a few days. Otherwise, you may have to live with the problem until your next complete iPhone upgrade.