what you don't seem to grasp is that unless you are trying to slow down the vehicle, putting energy back into the system will ALWAYS incur a loss, therefore not putting as much energy as was taken out. Going down a hill maintaining speed requires slowing down the vehicle (gravity), that can put the excess energy in the system. Same as braking where you are expending the vehicle kinetic energy. In a ICE, the braking converts the kinetic energy into heat on the brake parts. In constant or accelerating motion, energy will be lost trying to put it back.
Ok, and so why can't the free wheel that is turning freely, otherwise that is mainly used for stabilizing the structure as it rolls down the road, not produce some form of (slight drag effect on the overall), electrically generated charge through a created highly efficient mechanism that can transfer that charge back to the secondary battery pack for a boost in replacement stored energy there ??
We have used paddle wheels in river's, we've used windmill's, ocean currents, hydro's powered by water flow based upon a primary energy source that is propelling the necessary flow that is then taken advantage of to create the alternative energy source that is then transformed into or used for another purpose as a side effect captured from the original source of energy that propels the forces that are then being tapped into.
In dams we have the primary energy source that is the water flow, and then we are taking that flow and creating a secondary energy source by way of that flow in which we then convert in a step down effect that puts that energy into a form that can be used and distributed. Now yes of course we have to depend on the rains to fill the reservoir in order to keep our flow strong or yes both energy sources will eventually die out due to drought etc.
So it's the same thing in effect, where as the water table drops, the flow decreases, and the generated power becomes less and less, but that which was stored might keep us going until the rains return hopefully in short order.
So for the max period in which the EV is at it's strongest, then the regenerative process will also be maximizing that period to create, but as the primary diminishes, so does the generating ability diminish in it's ability, but hopefully the generated power created during peak performance was saved in the secondary battery pack for the remaining miles projected to be completed once switched over too.
Yes at some point the over night charging station will come into play, but extending the miles is what it's all about during usage correct ?
