I did 7 months of a 26 mile commute on the highway in the SF bay area.
I had a plug at work to recharge, and I generally made it all the way.
Times I ran out of power involved too much top end (62) and too much
headwind. You should be fine at 30-40. I've got over 6k miles on mine
and have not noticed any drop off in the batteries. I had a recall
issue that the factory took care of. I've found the factory and the
dealer to be entirely helpful.
-- Jim Robinson