that will be the question i asked on racechat then
i have had a reply from the brca regarding this it reads
Dear Simon,
LiPo cells are not allowed to be used at any BRCA sanctioned events during 2007.
Obviously they do not comply with any of the current battery rules, and none of the Electric Sections (within the Electric Board) have asked for them to be included in the rules.
The latest list of approved NiCd and NiMH cells for 2007 can be viewed on the BRCA website.
Go to the Electric Board Section and 'click' on the battery homologation list.
Best regards,
Paul Worsley. (Secretary, BRCA Electric Board)
from what i can gather they are legalish but not in brca events but you are covered by the brca for insurance purposes