I have not heard any official info on this, but I suspect that the more efficient your are the image will come more into focus. I think at as it nears 100% it will look like your i3 just like the image on another page of the app.
Where the animation stops appears to be related to percent efficiency. When I was giving people full-throttle test rides I managed to get the efficiency down to 11% and the animation stopped with only a few blips in the center and everything else was still blank. Mindmachine is probably right that it does something interesting when you get all the way to 100% efficiency.
I also find the lack of documentation for the app kind of annoying. I didn't realize you could touch the state of charge reading when the car is charging to get the estimated time when the charge will finish until I tapped it by mistake. I also realized that the app can give you bad data when it loses connectivity with the car. The cell phone reception in our garage is terrible and the app told me the car was happily charging about half an hour after the breaker blew and the car clearly wasn't charging. I need to figure out how to add the i3 to our microcell. And get a dedicated circuit for EV charging installed in our garage.
