What is a 25kW 280Ah battery? Assuming you meant 25kWh then 25kWh / 280Ah = 89.3V. That's a strange battery voltage.
Something about these numbers isn't right.
A 12V 280Ah battery would be 3584Wh and it can handle a 2kW load for 1.79 hours.
A 24V 280Ah battery would be 7168Wh and it can handle a 2kW load for 3.58 hours.
A 48V 280Ah battery would be 14,336Wh and it can handle a 2kW load for 7.16 hours.
Those durations assume you use 100% of the battery capacity which you are not likely to do.