In addition to a normal energy-saving mode, the LG device has another, maximum battery saving mode, which extends the battery life, which can be up to twice as long depending on the model.

Extended energy saving mode

The advanced battery saving mode merely deactivates the vibration, limits the background activity and data of apps, and limits the brightness to a maximum of 90 percent.

Maximum Power Save Mode

This sets the LG device to allow maximum battery life, and activates the following restrictions:

All settings and restrictions can be edited and saved once the respective mode has been activated.

Android 9 | LG UX 9.0
Power saving mode -  Open the  Settings
Power saving mode -  Tap on  General
Power saving mode -  Tap on  Battery
Power saving mode -  Tap on  Battery saver
Power saving mode -  Choose between  Off ,  Extended  and  Maximum
Power saving mode -  Confirm with  Turn on
  1. Open the Settings
  2. Tap on General
  3. Tap on Battery
  4. Tap on Battery saver
  5. Choose between OffExtended and Maximum
  6. Confirm with Turn on

LG Instructions