HP Compaq NC6220 Getting Started page 15

Hardware Setup
When the notebook receives AC power, the battery pack begins
to charge and the battery light is turned on. The color of the
battery LED is amber when the battery is charging. The light
changes from amber to green when it is close to full charge
capacity. When the battery pack is fully charged, the battery light
is turned off. For more information about the battery light, refer
to "Lights"
It is recommended that you leave the notebook connected to
external power until the battery pack is fully charged and the
battery light is turned off. A partially charged new battery pack
can run the notebook after software setup is complete, but battery
charge displays will not be accurate until the new battery pack
has been fully charged.
1–10
in Chapter 4.
Getting Started