You may be familiar with Optimized Battery Charging, a feature that automatically slows down your iPhone’s charging speed when the battery goes above 80 percent. With iOS 18, Apple lets you manually set a charge limit to improve your iPhone’s battery longevity. I’ll show you how to use it.
How to set a charge limit for your iPhone’s battery
Before we proceed, it’s worth noting that this feature is only available on iPhone 15 and iPhone 16 models running iOS 18 or later. If you have one, you can follow these steps to set a charge limit.
Lowering the charge limit below 100 percent will automatically disable Optimized Battery Charging on your iPhone. Since you’re manually limiting the battery charge to anything below 100 percent, this feature becomes irrelevant.
For battery calibration, your iPhone will charge to 100 percent each time. Otherwise, it will stay at the charge limit you set. Charge limits are a great way to maintain the health of your iPhone’s battery.
Why you should limit your iPhone’s battery charging capacity
Charging your iPhone to 100 percent and then draining it to 0 puts a lot of stress on the battery. Lithium-ion batteries in smartphones and other devices wear out faster when regularly charged to 100 percent. That’s why iPhones and other devices slow down their charging speed after 80% and switch to trickle charging.
A lower charging speed reduces the amount of heat generated and the cells gradually reach their maximum capacity, reducing wear and tear. Trickle charging may be one reason why your phone is charging slowly.
With Charge Limits, you can set your iPhone to never charge to 100 percent. Instead, you can limit it to between 80 and 95 percent to extend the battery life. This feature is only useful if you don’t use your iPhone a lot and are always near a power socket.
Heavy users may have to live with an iPhone dying by the end of their workday without a charger. For them, replacing the phone’s battery after a few years is a better option.