Deep OBD Scanning Android App for BMW, VW, Audi, Seat, and Skoda
 

I have not seen this discussed on this forum before and was just advised of this Android app today. I am still exploring it myself, but it seems to deliver additional vehicle specific data for BMW, VW, Audi, Seat, and Skoda (as well as Mini most likely) that other OBD apps just don't. It is open source and free.

Deep OBD for BMW and VAG

For my i3, I've been able to monitor HV battery voltage, current draw and charge values, cell temps, and reported torque of all things (although I believe it is sensor interpolated and not the correct value). This obviously opens the door to other kinds of test data and it has a logging option. I can see the torque value as being useful in measuring rolling resistance for one, and much more reliable than coast-down numbers since it can be read continuously.