Asus R552LF - Manual (Page 28)

8 Notebook PC E-Manual
Getting started
Charge your Notebook PC.
A. Plug the AC power adapter into a 100V~0V power source.
B. Connect the DC power connector into your Notebook PC’s power
(DC) input.
Charge the Notebook PC for 3 hours before using it in
battery mode for the first time.
NOTE: The power adapter may vary in appearance, depending on models
and your region.