I'm running 3s 1300mah on the axle, about 50c, they last 30 minutes each, I use Scotch extreme fasteners with an o ring.
On my comp crawler I'm running smaller Brood 850 mah 35c 3S, get about 20 min each
I don't want all the weight up top on mine, so I never ran anything larger in size
Hang up and Drive