I have a Zippy 5800mah 4s battery in mine. I also use the OFNA glow driver and have it preset inside my starter box.
I can start every car at your track, for every heat, for a month without recharging.
I'm actually thinking about adding two more 5800 lipos because I have them sitting around collecting dust. I like a concrete heavy non-tippy box, I though about adding a steel weight, but batteries are free since I allready have them. Could go for a year straight! I use Deans plugs on all of them.