If you replace your iPhone every year or two with a newer model, you shouldn’t have battery problems. But for those who have iPhones that are two years old or more, they may experience battery problems due to the many charging cycles that the battery has been subjected to.
If you are facing battery problems such as: quickly decreasing the charging rate, or the phone turning off suddenly and repeatedly, you can check the health of the iPhone battery in the settings application built into the phone, to determine the most appropriate time to replace it.
Scroll down and tap the Battery option.
Click on the Battery Health & Charging option.
The current battery capacity will appear at the top next to the (Maximum Capacity) option.
When should the iPhone battery be replaced?
iPhone batteries are designed to retain up to 80% of their original capacity at 500 full charge cycles when operating under normal conditions. And when the iPhone battery capacity drops below 80% of its original capacity, a feature called (performance management) automatically activates to help prevent unexpected shutdowns.
If you see an alert indicating that the battery health is deteriorating on your phone and you begin to notice that the phone’s performance is declining, head to the Apple Store or contact Apple Support to obtain an Apple-approved replacement battery. (Arabic)