I believe that the battery must be able to run all day or at least be easily swapable with minimal interruption of service. With the Accu-Vote paper ballot system, if the power goes out, the people who arrive at the polling place can still vote and leave. The paper ballot can be processed later. With the DRE system, if the power goes out all day and you have a 3 hour battery backup, nobody can vote after three hours. A DRE system needs to be capable of running all day from just prior to opening the polls to an hour after closing the polls (approx. 14 hours/ FEC says 16 hours).
A battery large enough to run a system all day long would be expensive, so a swapable battery system would be my choice. That is, put a minimum capacity battery into the DRE to run it for 3 hours (that would keep product cost down per unit), but make it easily accessible so it can be swapped out quickly (minimizing disruption to voting) if the power is out longer than 3 hours. Trouble shooters on the road on election day can carry spare battery packs with them in the event of a power outage longer than 3 hours.
I disagree with Mickey. Right now, we competing with small screen DREs. Right now, sales people are having to justify the cost/benefit of a large screen. What if a customer doesn't mind a small screen unit? Wouldn't you like to have the option to sell them what they want and be competitive? Global cannot sell 15" DREs for the same price that the competition is selling 10" DREs, but if we are capable of producing a 10" Accu-Vote TS, we can be competitive.
Having said that, multiple options that have to be implemented on the manufacturing floor are what kill me in production (as opposed to PCMCIA pluggable options which are easy to implement). To stay ahead of orders, I have to manufacture to what we think is going to be the flavor of future sales. Having multiple flavors of a product means having to manufacture a bit of everything and not having enough of one thing come shipping time. But if the flavors are kept to a minimum of two (say vanilla and butterscotch ripple), I can manage production stock more effectively. I think those two flavors should be the 10" and 15" screen option.