How can I get my iPhone to charge to 100% full? Why does my iPhone stop charging at 80 percent?
The staying power of an iPhone battery is tied to its chemical age, which can be influenced by factors like temperature and charging patterns. From iOS 13 forward, the introduction of Optimized Battery Charging aims to extend battery life by delaying charging past 80 percent in specific situations. This feature leverages on-device machine learning to predict when your iPhone will be connected for an extended period, keeping it at 80% for a while then making sure it's fully charged before it's unplugged.
On the iPhone 15 and later, an additional option called "80% Limit" lets users charge up to 80 percent, with occasional boosts to full charge to recalibrate accurate charge estimates. This helps extend the longevity of the battery by keeping the lithium-ion cells in their happiest range of charge. Continually charging to 100 percent can deplete the battery's maximum capacity more quickly.
To switch off the 80% Limit navigate to Settings -> Battery -> Battery Health & Charging -> Charging Optimization and select "Charging Optimization" or "None". Deselecting "80% Limit" and restarting your iPhone will ensure it charges to its full capacity.