I am curious about that too although I believe that the system is smarter than me. If the battery doesn't need charging then I believe there would be no regeneration and even in L it would just coast. It is an electric motor/generator and to the best of my knowledge, has no parts that wear. I don't think the way I drive it is damaging or accelerating wear but I am very receptive to opinions to the contrary.

I actually like the way it performs in L versus D - when I let off the gas pedal, the regen braking makes it feel like a standard shift car does when coasting in gear.

Is there any way to tell the battery state? Mine always just says avail elec normal ot whatever it is.