Try to update your Chromebook. If that does't help try to reset all Google Chrome flags. To reset them, do the following: (1) Open chrome. (2) Type chrome://flags in the box. (3) Press Enter. (4) Click Reset all. (5) Click Restart to restart your computer.
(1) Try a different cable or charger (2) Look inside the charging port to see if it is dirty. If the battery is draining easily it is probably time to change it.