This is just like the questions what slicks, what oil, what etc.... are you using. You will get many varied answers and many different things that work. I myself am using the highest amp Sears Platinum but it is a little expensive. In my opinion the best thing you can do for you race car battery is this.
http://www.batterymart.com/p-battery...y-charger.html
Usually one battery is plenty with an alternator. This is just my opinion though. This weekend I made 13 passes running 400gph fuel pump, Mezier block mounted water pump, 7" fan on tranny cooler, 7" fan on radiator, electric shifter, data recorder and was letting the water pump and fans run while downloading recorder between rounds and didn't have to touch the battery charger.
Curtis