When your iPhone battery refuses to hold a charge very long, the solution could be changing a setting that you rarely, if ever, pay attention to.
Our iPhone batteries can be fickle. If we load our phones with too many resource-consuming apps or forget to enable or disable certain settings, that alone can have a major effect on battery power. And one of the settings that has the most potentially detrimental effect on your battery is: your brightness setting. You are likely only consider this setting when you want to boost your brightness to see better, but the brighter your phone’s screen, the more of an impact it has on your battery. For that reason: your brightness setting is the “essential” iPhone setting that will extend your battery life. Here’s what you need to know to lessen its impact on your phone.


Turn On Auto-Brightness
The Auto-Brightness setting adjusts your screen’s brightness so that it is appropriate for your setting and needs. In other words: if you enter a dark room, this setting prompts your phone to become brighter; brighter rooms alert your device to dim its brightness. You can even enable True Tone to adjust the screen’s color temperature to suit the light around you.
To enable Auto-Brightness, go to Settings > Accessibility > Display & Text Size > Auto-Brightness.

Use Dark Mode
Switching your phone to Dark Mode changes your phone’s interface from a light screen with white backgrounds and black text to a dark screen with a dark black or gray background and light text. This significantly reduces the impact your screen’s brightness has on its battery. This setting can even prevent eye strain when you’re scrolling the internet or reading messages at night.
To enable Dark Mode, go to Settings > Display & Brightness > Appearance > Dark.