4. For the best results when charging another phone, position the devices like this:
You'll feel a short buzz when the devices connect.
Extend battery life
Choose settings that use less battery
To get the most life from your battery:
•
Connections: Turn off Bluetooth and GPS when you're not using them.
•
Wi‑Fi: Turn on Wi‑Fi when the phone is in a location with Wi‑Fi coverage.
•
Screen: Turn down screen brightness, change to Dark theme, and set a shorter screen timeout.
•
Sync: If you don't need it, turn off automatic syncing for all accounts. This means you won't receive 
notifications when updates occur and you'll need to manually sync to get new emails.
Temporarily conserve battery power
Use Battery Saver mode to keep going on a low battery.
Also, avoid these battery-intensive activities until you can charge:
•
Recording or watching videos
•
Listening to music
•
Taking pictures
•
Using Live (animated) wallpaper
See what’s using your battery
To see if a specific app or service is draining your battery:
1. Go to Settings > Battery > Battery usage.
2. Swipe up to view the list of apps and features using power since the last full charge.
3. Touch the app or feature using a lot of power.
4. Under Manage battery usage, touch options for reducing the power usage.
Settings : Battery
173