Wow...just got back from another 2 batts..well, I stopped before they died. The first one is a 160mah/25c thunder power batt I got as a second batt when I got my mCX last year and it ran 16 minutes before I stopped. The second is the batt that came with it, a 12c/150mah and i stopped after 13 mins as the wind was picking up.
About 30 seconds into the flight on teh second batt I heard the motor cut out and in a couple of times and it seemed OK after that...not sure if some form of interference or the included batt is questionable...others have had similar issues and a new fuse (esc I suppose) fixed it. We'll see how it goes.