There is a long lasting argument in the drone community about which is the best configuration for mounting your battery pack on your quadcopter? Most would probably say to strap the batteries closest to the center of gravity as possible for maximum stability, but if that is not possible, is it better to have the batteries at the bottom or the top?
In this case we will be looking at a four engine craft that tilts in the direction that it moves… so if you had to choose having the battery pack would it be top or bottom… meaning above or below the center of gravity? The simple answer would be to have your quadcopter battery placement below the center of gravity for the simple reason that when there is a crash it becomes less likely for the machine to tilt over (as the battery is weighing the machine down) and therefore less likely the your propellers getting damaged by hitting the ground and needing replaced.
Also mounting the batteries above the center of gravity mean they will be above the geometric center and will be more inclined to want to tip. This causes a gravitational torque that will constantly be applied to the quadcopter which ultimately means the controller having to work harder to keep the craft horizontal and therefore use more battery power, meaning less air time to fly your machine. This especially can make all the difference for a racing drone battery life where conservation of energy can make the difference between winning and loosing.
There really is no quick fixes other than getting your batteries as close to the center of the hub and as close to the center both horizontally and vertically as possible. The closer you get to this the less the control has to work and the longer your battery life will be giving you an few extra minutes of enjoyable piloting time… remember, it is also about have fun too!