What does it mean when the battery light is blinking amber on the HP EliteBook 9470m?

A blinking amber battery light means a battery that is the only available power source has reached a low battery level. When the battery reaches a critical battery level, the battery light begins blinking rapidly. When the battery light is solid amber, the computer is connected to external power and the battery is charged from 0 to 90 percent. (Page 20)