Yes, battery should be standalone device, because it needs a measure_battery capability and device class ‘homebattery’.
So perhaps you set the home battery flag but the measure_battery capability is not the one from your battery.
Here is the HowTo 
Yes, battery should be standalone device, because it needs a measure_battery capability and device class ‘homebattery’.
So perhaps you set the home battery flag but the measure_battery capability is not the one from your battery.
Here is the HowTo
