matt,

I opened the NSX-R but I can't see what kind of batteries it has. It's the same green plastic wrap that's in the regular DigiQs.
I don't know how to take the circuit board off to get to the batteries, sorry I don' t have more info on it. I'm too scared to take apart the whole car just yet. But the car does run for about 12 or 13 minutes on a charge.