1 battery or 2

I'm working on wiring up my Dart for bracket racing. I'm not using an alternator. In talking with a racer friend, he thought 1 battery would not keep up to the demand I'm putting on it, and suggested I add another battery. The car has electric water and fuel pump, fan, MSD, transbrake, etc. etc. His main concern was during round robin competition with little or no time for charging. My battery right now is a red optima. What do you guys think?