Hi,
This is from the User Guide,
Charge indicator status Meaning
Lit in orange: The battery pack is charging.
Blinks along with the green power indicator : The battery pack is running out of power.
(Normal mode)
Blinks along with the orange power indicator : The battery pack is running out of power.
(Sleep mode)
Blinks fast in orange: A battery error has occurred due to a failed battery
pack or an unlocked battery pack.
Here is a link to the User Guide.
https://docs.sony.com/release/VPCEB3_Series.pdf