JOTTDUINO:
Can anyone confirm if is OK?
Yes, that´s fine. You can be sure, when the Service ID is responded as SID + 0x40.
Then the request was right and the response will be valid.
Otherwise you are getting something like that:
0x80 0xF1 0x12 0x02 0x7F 0x21 0x10 as an Error. The second value might give you an idea what went wrong. But that seems to differ from ECU manufacturer to manufacturer.
Battery is quite complicated, I guessed a lot and don´t think it is the right value. It seems to be the loading voltage from the generator.