FX3 - External Power Supply

[yaronwn]

Hi
Where can I post a question regarding FX3/A7S3?
My question is -
Could you please help with an answer for something me and some of my colleagues cameraman are trying to figure out.
When you connect an external battery with a USB cable to the USB-C port of the FX3/A7S3 while the internal Sony battery is in the camera, what is happening?
Does the camera takes its power from the external battery?
Does it take it from the internal battery and the external battery charge the internal battery at the same time?
Dose the internal battery gets to be charged at all?
Does it being charged only when the camera set to off?
Is it not healthy for the Sony battery to work this way?
I couldn’t find any official answer from Sony for these questions..
Thank you very much.
Weinstein Yaron