Owners of Inventist's Solowheel Xtreme can use this free app to display the battery charge and speed on their iPhone. (Xtremes only. Solowheel Classics do not support Bluetooth.)

The battery gauge is based on the voltage reading transmitted by the Xtreme. The fully charged voltage is displayed as 100%. Empty on the gauge is when the Xtreme is going to start wobbling to force you to get off. Batteries do not drain at a steady rate. In normal use, the Xtreme's voltage drops off quickly after being fully charged and then stabilizes during the ride. Please don't assume the battery charge percentage translates directly into how far you can ride.

When descending downhill or slowing down quickly, the Xtreme uses regenerative braking. The battery gauge will temporarily increase on downhills as the Xtreme uses your kinetic energy to charge the battery. The gauge will provide a more accurate battery reading once you're back on level (or uphill) terrain and the battery charging stops.

If your Xtreme has non-standard Soloware firmware, it may not work with this application.

Currently the only data sent over Bluetooth LE from the Xtreme is battery voltage, speed, and direction. (No distance.) You probably already have several amazing GPS navigation apps on your phone that can provide distance. The Xtreme's blue LED battery meter doesn't provide much warning before your ride ends unexpectedly short of your destination. The most important feature we wanted to get out quickly is a better battery meter. Please remember that this app is limited by the capabilities the Soloware firmware provides and upgrading the firmware in Xtremes with future improvements will take time. Inventist has been very helpful and supportive on this project. I'm sure they will welcome and read your suggestions for improvements with great interest here.