Hey HemiEd. I have always tried to run an alternator on any race car I have taken to the track. I have tried doing without and charging the batteries between rounds but it never really works very well. These high tech MSD ignitions these days really place a load on the electrical systems and I want to be sure I always have at least 14 volts charging at all times. Plus it puts out 140 amps and I need every bit of them.