Just for fun, I made a graph that shows battery voltage distribution at the last German competition.
And as a bonus:
A grand total of one team would have been eligible to run in the US
(namely the Indian team with the 134V battery. The guys from Beijing actually cited 302V, so I guess they wouldn't have been allowed either)
Update: just found out that the 300V team runs 2 300V batteries in series, so actually 600V. I've updated all graphs accordingly
Thijs