> Regenerative braking improves efficiency even without careful driving, additionally you can drive carefully and improve your efficiency even more. This isn't the same as suggesting current regenerative braking isn't "good enough" for start stop applications.

I've never said it doesn't help. When the bar is in the right section, that means that your regenerative braking is operating at peak capacity, with extra friction braking applied on top.

> Braking will always involve energy loss, that's just physics. Over time we can improve how much energy is regained during braking but again that it can be better does not prove that it's not worthwhile now.

The energy loss of regenerative braking is some XY%. The energy loss of friction braking is 100%.

The optimal way to drive with regenerative braking is slow and steady braking. So that you are eating XY% energy loss in your braking energy, and not "Partially XY%, partially 100%". Most people drive in a way that would put them in the latter category.

As another poster mentioned, its quite possible for cars with $10,000 batteries to usefully absorb more energy through their regenerative braking.