The weight of the battery won’t affect the energy needed to keep a car at a steady highway speed. The energy needed is just whatever losses come from friction, air resistance, etc

At 70mph most energy is lost to wind resistance.

EVs are also heavier, which increases rolling resistance on the tires. This lead to the formulation of stiffer tires for EVs to counteract that effect.

The weight of the battery is related to the amount of friction.

> Plus as you point out you don't get as much regenerative breaking

Regenerative breaking is not a benefit compared to steady driving, it's a waste of energy due to the second law of thermodynamics.

It's only a benefit when you compare it to non-regenerative breaking.

Yes. When I had a Nissan Leaf for a couple of months, I couldn't make it to the office and back without a partial recharge on the way home. But I discovered if I got off at an exit fifteen miles earlier than normal and took surface streets, I could make it home with a bit of capacity to spare. That's not something that would have been good for the battery if I did it every day but at the time I was going into the office about once a week so it worked out fine. Plus I was using the 110V charger at home, which would take more than the next morning to charge the battery fully.