Asus K53sd rev 5.1 "battery is charging icon and orange led" without charger plugged

[kosmo]

i attach only battery to the laptop and it show orange led,when it loads windows right below corner it sais battery is charging , i plug the charger and its charging normaly, i remove the charger and keeps say battery is charging, with charger plugged in when it charge full the led becomes green and after i remove the charger the green led of full charge is still on. any ideas?