Last year Apple admitted it slows down older iPhones such as the iPhone 6, iPhone 6S, iPhone 7, and iPhone SE. Got a newer iPhone? Read down for news on how it affects you. 

These phones have aging lithium-ion batteries that might cause random shutdowns. So, to prevent them from shutting down, Apple slowed - or "throttled" - the performance of those phones. 

Users weren't that impressed that Apple was fiddling with the performance of their devices without telling them - even if the controls would make the actual device last longer.

So Apple apologised and released an update - iOS 11.3 - with a new Battery Health tool as well as the ability to turn off the iPhone's throttling ("battery management") feature.

Battery replacement program for iPhone 6, 6S, 7 and SE

At the same time it announced a battery replacement program for older iPhone batteries - iPhone 6, 6Plus, 6S and 6S Plus, 7 and 7 Plus and iPhone SE.

The scheme will set you back £25/$29 - a huge discount on Apple's usual service cost. The scheme ends on 1 December 2018 so you haven't got long!

Battery management on last year's iPhones

However, the battery management issue has raised its head again as Apple has revealed that the recent iOS 12.1 update brings the battery management features to iPhones that are just a year old - the iPhone 8, 8 Plus and iPhone X. Presumably the management will come to iPhone XS, XS Max and XR in late 2019.

Apple's official iPhone battery and performance notes say that the effect on the newer devices may not be as profound though: "performance management may be less noticeable due to their more advanced hardware and software design".

So let's look at how Apple's Battery Health tool works.

  • Apple iOS 113 rolls out Battery Health tool new Animoji and more image 1

What is the Battery Health feature? 

iOS 11.3 and later has a Battery Health tool built in. Just go to Settings > Battery >Battery Health. From there, you'll see information about your iPhone's maximum capacity and peak performance capability 

You'll also see if your iPhone is being slowed by Apple's throttling ("performance management") feature.

Our 2018 iPhone X is showing as having a 93 percent battery capacity a year after it was first new. Apple is not yet throttling the phone though: "Your battery is currently supporting normal peak performance".

You'll even see whether your iPhone needs service and can subsequently turn off the controversial throttling ("performance management") feature that's throttling your iPhone. And finally, there is one other battery-related change in iOS 11.3, according to Apple:

"iOS 11.3 improves this performance management feature by periodically assessing the level of performance management necessary to avoid unexpected shutdowns. If the battery health is able to support the observed peak power requirements, the amount of performance management will be lowered. If an unexpected shutdown occurs again, then performance management will increase. This assessment is ongoing, allowing more adaptive performance management."

How to disable throttling on an iPhone

The ability to disable - and even enable - throttling is only available for iPhones more than a year old with iOS 11.3 and later.

Under Battery in the Settings app you'll notice the Battery Health option. Tap it. You'll then see a screen with a link to more information about lithium ion batteries. Below that, you'll see your battery’s maximum capacity.

If this indicator is under 80 per cent, you'll see another message at the bottom of the screen that warns your iPhone's battery is “significantly degraded”. There will be another link that will point you to a page about how to get your phone serviced. 

Disable 'performance management' feature

If your device has shutdown due to battery degradation, this same screen will tell you that “performance management has been applied to prevent this from happening again”. There will also be an option to disable the throttling. You can’t enable throttling (the "performance management" feature) until you experience another shutdown. Your iPhone will auto-enable it should that ever happen.

What do those percentages mean?

AppleIphone Battery Health Explained How To Disable Throttling With Ios 113 image 2

In the Battery Health menu, you'll see a percentage that indicates your iPhone battery's maximum capacity, followed by a message explaining your iPhone battery's peak performance capability. The message you get depends on the percentage shown.

For instance:

  • 100 percent: Your battery is currently supporting normal peak performance.
  • 95 percent: 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. Disable...
  • 79 percent or less: Your battery's health is significantly degraded. An Apple Authorized Service Provider can replace the battery to restore full performance and capacity. More about service options…
  • Unknown: This iPhone is unable to determine battery health. An Apple Authorized Service Provider can service the battery. More about service options…

Maximum capacity and peak performance

Apple explained that maximum battery capacity measures your iPhone's battery capacity relative to when it was new. Batteries will start at 100 per cent when first activated and will have a lower capacity as the battery ages. According to Apple, a normal battery is designed to retain up to 80 per cent of its original capacity at 500 complete charge cycles when operating under normal conditions.

Now, as far as peak performance capability goes, it is the ability of your iPhone's battery to supply adequate charge. If your iPhone's battery maximum capacity is under 80 per cent, then its health has been significantly degraded and it needs replacing.