Registering and unregistering BroadcastReceiver in a fragment

My app has an action bar with 3 fragment tabs. In the second fragment I register and unregister a BroadcastReceiver. I unregister the receiver in onPause and register it in onCreateView and in onResume.

getActivity().registerReceiver(this.batteryInfoReceiver, new IntentFilter(Intent.ACTION_BATTERY_CHANGED));

and

getActivity().unregisterReceiver(batteryInfoReceiver);

1) Is it all right to register the same reciever twice (in onCreateView and onResume)?(is it harmless?)

2) Is it enough to just register the reciever in onResume?