I run a Yellow Top Optima myself... and no alt. The most passes I have made at one event was 6, all with no problems and no charging between rounds. In addition, I start it up to drive it over to the tech station, start it to drive it back to the trailer, start it in the staging lanes, start it up at that end of the night to put it on the trailer, and start it to test-run the engine the next day I am going to race (approx. 18-20 times per charge) ....all on the same previous charge. I then pull the batt. and charge it before actually going out to the track. I have an MSD ignition (6AL) that (per the advertisment) will run full voltage with the battery down as far as 9.5 volts. I run an electric water pump and fuel pump, as well a one taillight. No problems so far. Sooner or later I will probably have to break down and buy a generator to charge the batt. between rounds. This is more expensive than an alternator. I just like the clean look afforded by having no belts or brackets on the front of the engine. Just my opinion.......at least right now. My thinking is....."If it ain't broke, don't fix it".
Jay
Jay