Interesting comment on this in yesterday's Sunday Times. Journo Nick Rufford describing driving an EV after consulting one Wayne Gerdes, the "world hypermiling champion":
"I’ve been driving electric cars on and off for a while now, and one mistake I’ve been making, according to Gerdes, is to use maximum regen (regeneration is the amount of energy an electric car recovers when it slows down). The common perception is that selecting the highest level of regen saves energy. This, Gerdes says, is true only when you’re stopping and starting – during city driving, for example. When you’re cruising it drains the batteries faster. This is because each time you lift off the throttle the car slows down sharply and needs a wasteful shove to get it back up to speed. “It’s great that electric cars have regenerative braking,” says Gerdes, 61. “It’s bad that people think it’s the be all and end all of fuel saving, as it’s not.” I therefore switched out of B mode – highest recuperation into D mode and selected the lowest level."