Ok, about time someone brought logic into the argument. If people are allowed to use these batteries in any main competition when the arent in the rules, then they should have a lower weight limit to everyone else. If a robot has the same voltage (give or take a bit) then it is a straight deduction from the 100kg with difference in th pack weight. If they are running a higher voltage, then the weight of the lightest battery setup at that voltage which is allowed in the rules is taken from the robot weight before the trial batteries are added.
So if you had 9kg of nicads say, then 100-9 is 91, and 2kg of lithiums then the robot weight limit should be 93kgs.

Personally I think these batteries do need testing under high stress conditions. Specs can tell us what a battery should do under normal circumstances, what we do with them is not anywhere near normal. I dont mind either way, wether they are allowed in the UK champs or not, but if they are then something like I have suggested should be worked out.

It is upto the FRA to make a decision on this but the outcome must be fair to all.