Sony PCG-R505JE Primary Quick Start Manual page 29

The battery indicator on the front of the notebook indicates the status of the
battery pack.
Battery Indicator
Battery Pack
(supplied)
Battery Indicator
Status
On
Single blink
Double blink
Off
✍
Both the battery and power indicators blink when the battery is running out of power.
To remove the battery pack
You can remove the battery pack while your notebook is on or off. However, if
you remove the battery pack while your notebook is on, make sure the notebook
is connected to the AC adapter.
1 Close the cover of the notebook.
2 Slide the lock lever to the UNLOCK position.
Meaning
The notebook is using battery power.
The battery is running out of power.
The battery is charging.
The notebook is using AC power.
Connecting a Power Source
Battery Indicator
29