The documentation says the default value is false, yet when tested on two devices (iPhone 7 15.8; iPhone XS 17.4) the value is always true unless explicitly set to false. Is the documentation incorrect?
UIDevice.current.isBatteryMonitoringEnabled value is always true
As the state of battery monitoring for your app is process-wide, it is likely that something else running in your app requested battery monitoring before you checked the value.