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How to turn on 80% charging limit on the iPhone 15 to save battery health

Apple may have just fixed its biggest iPhone battery problem, and iPhone 15 users get first dibs. Here's how and when to use it.
Written by June Wan, Reviews Editor
iPhone 15 optimized charging
June Wan/ZDNET

The iPhone 15 series is officially available, and whether you already have a device in hand or are anxiously waiting for one, a recent feature discovery should be at the top of your initial set-up agenda.

The feature is called "80% Limit" and is tucked within the deeper end of the iPhone 15's Battery settings. When toggled on, the iPhone will limit its charging capacity to 80% instead of the normal 100%. 

Also: Want the fastest iPhone? Choose this model on this network

While Apple doesn't actually explain why this feature exists, it's safe to assume that the charging cap is a direct response to the recent comments about the iPhone 14's battery degradation. These aren't fan theories, unfortunately; it's just the nature of lithium-ion batteries found in iPhones and other devices, with the maximum capacity slowly degrading every time it completes a charge cycle.

Capping the iPhone 15's charging to 80% reduces the likelihood of battery degradation, though it may not always be in your best interest to have the feature turned on. More on that later.

How to turn on 80% Limit on the iPhone 15

What you'll need: At the time of writing, 80% Limit is only available on the iPhone 15 series, which includes the iPhone 15, iPhone 15 Plus, iPhone 15 Pro, and iPhone 15 Pro Max

Also: Your Apple device may be eligible for a major software update. How to check and download

The feature is clearly not processor-exclusive, as the non-Pro models operate on an A16 Bionic chip versus the A17 Pro on the more expensive iPhones. Therefore, the chances of Apple extending the feature to older models are still likely.

1. Access Battery Health & Charging settings

First, open up the Settings app and scroll down to the Battery tab. Then, tap on Battery Health & Charging.

iPhone 15 Optimized Charging

Tip: A new iPhone 15 should be at 100% Maximum Capacity.

June Wan/ZDNET

2. Toggle on 80% Limit

Now tap into Charging Optimization and you'll be presented with three options: 

  1. Optimized Battery Charging: Prompts the iPhone to trickle charge up to 80% overnight and then tops up to 100% as you're about to wake up.
  2. 80% Limit: Caps the charging at 80%. Apple says the iPhone will occasionally charge to 100% in order to maintain a more accurate battery state-of-charge estimate.
  3. None: Keeps the iPhone's charging capabilities flexible.

Tap on 80% Limit to turn it on.

Also: Battery bad after installing iOS 17? Try these 7 tips

While you're on the Battery Health & Charging screen, you'll also find the maximum battery capacity of your iPhone, which, if it's an iPhone 15, should be at 100%. If your device shows a lower value, reach out to Apple support as there may be a potential defect with your battery.

When you should (and when you shouldn't) use 80% Limit

You should use 80% Limit if...

  • You want to preserve the battery health of your iPhone, whether it be for longevity's sake or better resale value.
  • You're able to get through a day of average to high usage without battery concerns. This is mostly the case with the larger iPhone models, iPhone 15 Plus and iPhone 15 Pro Max.

You shouldn't use 80% Limit if...

  • You're concerned that 80% battery is not enough for a day's use. Perhaps you're traveling and access to power sources is limited or need to use more power-intensive tasks like video capturing, GPS navigation, and gaming.
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