Lots of charging was available. They custom wired a big pile of NEMA 14-50 adapters that let everyone charge at once during the driver briefings between track sessions.
It actually worked quite well the way they did it. 15 minute sessions on the track, then about 1.5 hour breaks to get some charge and let the electronics and motors cool down. (Which they really needed).
There were so many MC240s and Roadster foundry kits in use that owners started to put tape labels on them to make sure they didn't get mixed up.