Apps and processes are listed from highest to lowest percentage of power consumption. Review any high or unusual battery drain.
From a Home screen, navigate: Apps icon > Settings.
From the Device section, tap Battery.
Tap BATTERY USAGE (at the top near battery percentage remaining) then review the Recent Battery Usage section for usage (e.g. Screen, Cell standby, Android System, etc.).
Percentage indicates the remaining battery life and/or charging status.