There are components on the FW16 mainboard that measure current, volts and watts as well as the smart battery.
I modified the EC firmware to measure these and output the data to a console.
So, i did not use any external measuring equipment.
The tests were done by another user, and the raw data, register values, emailed to me to process.
For clarity, the user was purposely trying to draw as much power as possible. FW16 with dGPU, max screen brightness, sound playing max volume etc.
It was all part of this epic thread (573 messages):