Measuring car battery voltage

[Robin]

Can someone tell. Which commands in that work?
I would like to see the voltage of the battery before and after starting.

Freematics Vehicle Data Logger V4
Features
Measuring car battery voltage with built-in voltmeter

[onche]

Actually I have the instantaneous voltage with the sketch provided, have you tried it ?

[Robin]

I am not tested original code, which become with device. But I use Freematics library and there making getVoltage() query, but always result is 0.0. Other kind of function from that library for OBD or GPS works like they should. So main question is, where can be problem, because all other works fine. I will also try that original scketch, for ensure how it works.