[MetalMan]

You mean 6400mah, but 120amps capable, right? But then you have to figure the formula for watts. watts=volts x amps. If a motor wants to use 700watts for a certain setup, then you would *in theory* get the same runtime as if you put it in series, because of the formula for figuring out watts. But, this doesn't work since at lower voltages and faster motors, the efficiency goes down and and you would get less runtime than the higher voltage/lower mah setup.