Yeah, a set up like this has a few other limitations too, most of which simply require changes to how we use our cars.

However, using capacitors vs a battery also saves a smidgen of gas for every mile driven and would outlast 4-5 normal batteries before needing any maintenance.

At the moment building a system like the one shown would cost you about the same as buying 2 car batteries, but can also be moved from car to car for years down the road since this system is rated for millions of charging/discharging cycles. If you coupled a system like this with a starterless system that's already been proven functional, you would save even more fuel as the starter itself gets taken outta the picture as well, meaning more weight being eliminated and hence more fuel saved as a byproduct.

Something I also found while lookin at this stuff is that a capacitor system like this is actually superior to a normal battery in extreme cold weather as the cold itself is zapping the available current in a battery, but has no effect at all on a set of caps, meaning it cranks the same, summer or winter