All rules should be on the BRCA website, in the relevant sections.
GT12 rules in the GT12 section:
http://www.brca.org/sections/subsect...12-rules/13572
Battery rules in the Electric Board section:
http://www.brca.org/content/homologa...-updates/14218
Specifically here is the:
1S lipo homologation list
Sport 1S lipo waiver