It takes about 3.5 hours to charge the hatchback from a 220V/40 Level 2 charger. A Range Plus feature adds 18 miles (29 km) of range, but Mercedes warns against getting carried away with that button-operated option. Using it nightly will reduce the life of the battery that lies flat between the front and rear axles, providing a low center of gravity.   

Aiding the recharging cause on the car itself is an automatic downhill regenerative-power system and an optional 4-level radar-based recuperation feature, a form of cruise-control that works in concert with the brakes.

The electric motor delivers 177 hp and 251 lbs.-ft. (340 Nm) of torque, about the equivalent produced by a 3.0L internal-combustion engine. The B-Class EV is no slow poke but in the interest of extending range, it’s top speed is electronically capped at 100 mph (160 km/h).

Mercedes describes prospective B-Class buyers as progressives who already own at least one vehicle. They’re people who are wired with a California mindset without necessarily living there. On the issue of how many of them might buy premium-brand EVs, Mercedes declines to provide sales projections for its new offering.

But Webster optimistically cites a growing interest in EVs in the U.S. “Electric was seen as frumpy in the past, but now it’s sexy,” he says. But not luridly so. Children under 18 are allowed in the 5-seater B-Class.

For automakers, the allure of EVs is not that they rake in lots of money. It’s that they help companies meet stricter government regulations on emissions and average fuel economy.

If a graceful and nimble car like the B-Class EV springs from those rules, then regulators have gone above and beyond the call of duty.

sfinlay@wardsauto.com