Bluetooth LE sensors: show battery info

[dennisguse]

No description provided.

[gordonel]

Is your feature request related to a problem? Please describe.
I'd like to be notified if it's time to charge my devices or replace the batteries in advance.

Describe the solution you'd like
When starting an activity, OpenTracks should read the battery level if available and notify the user if it falls below a user-specified level. Also, the app can provide convenient readouts in the notifications drawer as extra info

Describe alternatives you've considered
reading battery levels through nRF connect before a workout

[edern-appere]

This feature would be very useful ! My HR sensor has a small battery, I always wonder if it will last until the end of my cycling trip.

[dennisguse]

Parsing is already there; we "just" miss the UI.
Probably a notification would be sufficient in case of low battery (=<15%)?

[edern-appere]

Yes, a notification would be great !

Would it be possible to show the notification "at any time" ? For example, when starting the application, if the battery of sensor is already low (=< 15%) displaying the notification would inform that the sensor won't last very long before begining a road trip...