About Charge Limit and Optimised Battery Charging on iPhone
To improve the lifespan of your battery, your iPhone learns from your daily charging habits.
How your iPhone battery ages
A battery's lifespan is related to its chemical age, which is more than just the length of time since the battery was assembled. A battery's chemical age results from a complex combination of several factors, including temperature history and charging pattern. All rechargeable batteries are consumable components that become less effective as they chemically age. As lithium-ion batteries chemically age, the amount of charge they can hold diminishes, resulting in reduced battery life and reduced peak performance. Find out more about iPhone battery and performance and how to maximise battery performance and lifespan.
Improve battery lifespan with Optimised Battery Charging
Optimised Battery Charging is designed to reduce the wear on your battery and improve its lifespan by reducing the time your iPhone spends fully charged. It is available when Charge Limit is set to 100 per cent. When the feature is enabled, your iPhone will delay charging past 80 per cent in certain situations. Your iPhone uses on-device machine learning to learn your daily charging routine so that Optimised Battery Charging will only activate when your iPhone predicts it will be connected to a charger for an extended period of time. The algorithm aims to ensure that your iPhone is still fully charged when unplugged.
When Optimised Battery Charging is active, a notification on the Lock Screen states when your iPhone will be fully charged. If you need your iPhone to be fully charged sooner, touch and hold the notification and then tap Charge Now.
Optimised Battery Charging is turned on by default when you set up your iPhone.
To change your charging option with iPhone 15 models and later, go to Settings > Battery > Charging and choose an option. You can choose a charge limit between 80 per cent and 100 per cent in 5 per cent increments. When the charge limit is 100 per cent, Optimised Battery Charging is available.
To change your charging option with iPhone 14 models and earlier, go to Settings > Battery > Battery Health & Charging and turn Optimised Battery Charging on or off.
Turning off charging optimisations can increase wear on your battery and reduce its lifespan.
Improve battery lifespan with Charge Limit
With iPhone 15 models and later, if the charge limit is 100 per cent, you can also turn on Optimised Battery Charging. Your iPhone has these settings by default.
Your iPhone will charge to within a few percentage points of your chosen limit and then stop charging. If the battery charge level drops more than 5 per cent while connected to power, charging will resume, again charging to within a few points of your chosen limit.
If iOS determines that a charge limit will help preserve your battery's lifespan, you'll see a recommendation. For example, you may see "Based on your iPhone habits, a charge limit of 95% is recommended to help preserve your battery".
If you have Charge Limit set to less than 100 per cent, your iPhone will occasionally charge to 100 per cent to maintain accurate battery state-of-charge estimates.
If Optimised Battery Charging won't activate
Optimised charging is designed to only engage in locations where you spend the most time, such as your home and place of work. The feature won't engage when your usage habits are more variable, such as when you travel. Because of this, some location settings must be enabled for Optimised Battery Charging to activate.* None of the location information used for this feature is sent to Apple.
Follow these steps:
Go to Settings > Privacy & Security > Location Services and turn on Location Services.
Go to Settings > Privacy & Security > Location Services > System Services and turn on System Customisation.
Go to Settings > Privacy & Security > Location Services > System Services > Significant Locations and turn on Significant Locations.
Learn more
Find out what to do if your device stops charging unexpectedly.
Learn what to do if you think your battery is draining too quickly.
* Optimised Battery Charging needs at least 14 days to learn your charging habits, so it won't engage before then. Also, your iPhone needs to experience at least nine charges of five hours or more in a given location for Optimised Battery Charging to engage.