A day of maps, photos and messages can empty a full battery by mid-afternoon. These four changes stretch it to the evening on any recent phone.
Turn on the battery saver early, not at ten percent
Where to find it: iPhone: Settings, Battery, Power Mode, Low Power Mode. Android: Settings, Battery, Battery Saver
The saver cuts background activity, and it saves the most when it runs all day. Switch it on in the morning of a long day out, not when the warning appears. An iPhone turns Low Power Mode off by itself once it charges past 80 percent.
Turn the screen brightness down
Where to find it: Control Center on iPhone, Quick Settings on Android, the brightness slider
The screen is one of the largest power draws on any phone. A lower brightness level, with automatic brightness left on, buys real time without making the phone hard to read.
Download maps and music before you leave
Where to find it: Your maps and music apps, the download or offline option
Streaming and live navigation keep the radio busy. A saved map and downloaded playlists let the phone rest between uses.
Find the app that uses the most
Where to find it: iPhone: Settings, Battery. Android: Settings, Battery, Battery usage
Both systems list the apps that used the most power. If one you barely opened is near the top, close it or limit its background activity.
