paper: Battery Voltage in Robot Drivetrain Simulation and Modeling

[Al Skierkiewicz]

Andrew,
Nice paper! If you look at the battery voltage graph and compare to acceleration you will get an idea on what might be taking place. As the load changes, the current drawn by the motors change, and so to the voltage drop across the internal resistance of the battery. Of course, teams should also be aware that using other motors in the robot (at the same time as driving), also modifies the voltage drops and available current. The length and wire size also have a great effect on the current available to the motors. Longer and smaller diameter wire, adds significant resistance to the individual motors. At 100 amps, #10 wire will drop 0.1 volt per foot. So if the motor is wired with two feet of wire, the drop will be 0.4 volts since you must take into account both the red and black paths. If a team uses #12 for the motor path, double that loss.