How to keep your iPhone running at maximum speed instead of saving battery life

  • iOS 11.3 lets you control your iPhone's performance.
  • If you have an older iPhone, Apple might be slowing it down to preserve battery.
  • Here's how to turn that off, at the cost of battery life.

Apple just released iOS 11.3, which has a new beta feature that lets users check the health of their battery and make sure that their iPhones are running at peak performance.

Apple included this tweak after backlash in late 2017, when users complained that they noticed their phones slowing down. It turns out that Apple's software was automatically limiting performance during times when the phone was drawing peak power from the battery, in an effort to preserve battery life and avoid sudden iPhone shutdowns.

Now, you can make this choice yourself: with iOS 11.3, you can see the health of your battery and decide whether or not to sacrifice battery life for power.

Here's how:

  • Make sure you have iOS 11.3 installed. Go to Settings > General > Software update.
  • Go to Settings > Battery

You'll see this menu. Click on Battery Health (Beta):

iOS 11.3 battery health screen
Todd Haselton | CNBC
iOS 11.3 battery health screen

Now you'll see this page:

Checking the health of my iPhone battery using iOS 11.3
Todd Haselton | CNBC
Checking the health of my iPhone battery using iOS 11.3

As you can see, my iPhone X still has 98% of its battery health and is running at optimal performance.

If you have an older iPhone, you may see a lower battery health percentage. That's because batteries begin to deteriorate and lose their ability to hold a charge over time. If it's below 80 percent, you'll see a note that performance is being limited as a result.

You might see this option if your battery is aging.
Todd Haselton | CNBC
You might see this option if your battery is aging.

This means your iPhone is purposely saving power so that the battery doesn't automatically shut down when you don't expect it to.

If this is the case, Apple will show an option to disable the performance throttling. Tap "disable" if you want your iPhone to run at peak performance, but at the cost of battery life. Just understand that your phone may shut down suddenly, or sooner than you expected, as a result.