Soldato
uh........ rite.
The 'smoke' was the onboard fire extinguisher going off as the KERS system caused some sort of short circuit. the cockpit is the only major hole in the chassis, hence it excaped there, not that thats where the batteries are.
The batteries are on the floor of the car near the engine bay, as low as possible. The issue is that while they are ballast, they arent moveable, and move the CoG of the car backwards. There isnt enough moveable balast for them to move to the front to level it out and keep the cars light enough, which is why Kubica isnt using it. There are no KERS batteries by the drivers feet.
Ferrari said it wasn't fire extinguisher though... so it must have been some form of battery in there. Either that or all the electrical wires burnt out under there