A couple updates. First, I was able to reproduce the behavior when the app hangs on "Reading" and I still need to fix it :p Second, I'm working on adding the ability to both read battery statistics & information as well as battery registration in the app. This isn't in the beta yet but should be "soon." I'm actually planning on using the app to register a new battery in my dad's X5.

Examples (Note: this is extremely rough on the presentation!)
Old 335i DME (sits around a lot)



X5 35i sitting on a float charger, pretty sure the "60 Ah draw" is from me killing the battery while working on the CIC although the time isn't right




Another thing I've noticed is some oddness with flashed DMEs around the replacement mileage. Still trying to make sense of it. I can confirm the replacement mileage on my 335i is accurate for the most recent battery.