Ranges 20min to 18min...Most users that have or had V2's say go for at least 3 to 4 batteries. I went with 4 for after flying mine and foresee that need.
But I should point out 20 mins seems like forever when your flying. It's just the need to charge the battery again. And then the TX and the Tablet after a while too. I think the TX goes for about 2 hours (correct if wrong) but that's not replaceable.