batterysaver
nounUK /ˈbætəri ˌseɪvə/
US /ˈbætəri ˌseɪvər/
A batterysaver is a setting that helps your phone or toy use less power so it lasts longer.
I turned on batterysaver so my tablet wouldn't die during the car trip.
OTHER MEANINGS
2. A feature on a device that turns off things you are not using to save electricity.
The batterysaver dimmed the screen and stopped apps from running in the background.
3. A person or thing that keeps a battery from running out too fast.
This little app is a real batterysaver when you're traveling.
4. A mode that warns you when the battery is almost empty.
When the battery got low, the batterysaver popped up a warning.