There appear to be many good ideas involved, but will it be neccesary to cart so many batteries around?
looks as though the demo takes place at a trade show,so many demos may have been done thru the day, hence the need for extra batteries.
I ve installed the largest lithium ion battery made by Ballard, about the same cold cranking power as a car battery. It only weighs 2.5 pound and is tucked under the seat hump. The expectation is that it will run a starter something like the one in the demo.