[Al Skierkiewicz]

The limiting factor is how much current can you pull from the battery before the voltage drop across the sum of all resistance exceeds the drop out for the voltage regulators. The internal resistance on a new, fully charged battery is .011 ohms. At 400 amps that will drop almost 5 volts. Figure another 2 volts for other resistance and you now are below the threshold at which the voltage can be maintained in the DSC. when the voltage falls down to 4.5 volts, the 24 volts and the 12 volts for the radio will drop out.
My recommendation is to limit motor usage to below 300-350 amps at any one time. You can do this by ramping up the motors you are turning on and using delays to prevent them from all starting at the same time. A motor that is not turning is in stall and will draw full stall current limited only be the series resistance of the circuit feeding the motor. Typical stall currents of 115 amps for CIM motor is common on an average robot.