lots of variables at play, so we'd need more details on your gear, but i run a 4300 kv motor with 16t pinion and on a 6500 mah lipo, and my esc set to 80% current limit, get about 20 minutes around the track. my 7200 mah feels like it gets around 25 minutes or so. Showing up with both of those lipos charged gets me close to an hour of practice time. I've never timed it, but that's what I would guess.