On Apple Watch, I'm able to check the battery level and charging state within my WatchKit Extension by setting WKInterfaceDevice.current().isBatteryMonitoringEnabled = true then checking WKInterfaceDevice.current().batteryLevel and WKInterfaceDevice.current().batteryState.
While the WKInterfaceDevice.current() object is available on iOS, the isBatteryMonitoringEnabled, batteryLevel, and batteryState properties are not.
Is anyone aware of a way to access a paired Apple Watch's battery level and charging state from iOS?
It seems like it might be possible since Apple's Batteries widget shows the current level and charging state for a paired Apple Watch, although this may be using private APIs since it's a widget built into iOS.
For more context, see the post about what I was trying to accomplish on Medium.