Since the night hawk 280 uses the skyline32 controller with is compatible with base flight/cleanflight it is definitely possible to enabme telemetry to your taranis for battery voltage info. I have not personally done this myself yet with the nighthawk.
Here is a video on how to set this telemetry up with a naze32 board and taranis which should help. The only difference will be that the telemetry port on the skyline32 will be in a different location. One you have connected your RX telemetry port to the Quadcopter you just need to set it op on your taranis and cleanflight/base flight GUI.
As I mentioned I have not setup telemetry specifically on the night hawk, but this should work fine since its quite similar. If you have any issues let me know and I will take a closer look and help you.