Vijay Pattni06 February 2014

First drive: Electric Mercedes B-Class

An EV Benz with the motor from a 416bhp Tesla Model S? Consider us interested

What's that?

It's a near-production version of the Mercedes B-Class ‘Electric Drive', the latter part of that nomenclature referring to the fact that yes, it's electric. And drives.

A proper electric car, or one of those petrol-electric hybrid jobbies?

Full electric, with the drivetrain lifted straight from the Tesla Model S, no less. Daimler, you see, acquired a small equity stake in Tesla some time ago, and collaborated with the Californian company on the previous Smart ForTwo Electric Drive too.

So there's no range-extending petrol or diesel engine on board this B-Class, just wires, a motor, a battery and some power.

How much power?

174bhp and 251lb ft of torque, and a top speed limited to 100mph (to conserve battery life), which is quite a considerable step down from the Model S's 400-odd-horsepower output. But then, it was never going to be a 400bhp electric B-Class, because Top Gear isn't in charge at Mercedes. Mercedes is, and anyway, this thing will sprint from 0-62mph in 7.9 seconds via a single-speed gearbox, which is plenty for a B-Class.

But is it really a B-Class?

It is. The ED is built on the same production line as the regular B-Class, because it required no major structural change.

The current B-Class was designed with a sort of ‘semi-sandwich' floor, with a very convenient space in the middle of the car underneath the passenger seats, here dubbed ‘Energy Space'. Merc has fitted the 28 kW lithium-ion battery in this little gap, with the motor and rest of the electric gubbins up front in place of a normal combustion engine.

I'm guessing it's a bit lighter then?

You guessed wrong. It's around 300kg heavier than a standard B-Class, which is the equivalent of having something-amusing-that-also-weighs-300kg on board. Like a Californian sea lion. Or a baby elephant.

How long before I start worrying about running out of juice?

Ah yes, the problem of ‘range anxiety'. Merc reckons on average this B-Class Electric Drive can do 115 miles before recharging, but of course this is dependent on whether you drive like a loon, and whether it's really cold outside: temperature affects battery charge.

But stick the B to a 400V charger and it'll be full in one and half hours. There are also three driving modes - D-, D and D+ - which can be cycled through using the paddles on the wheel.

The first (D-) applies strong regenerative braking when coasting, the middle (D) adjusts the regen a little less noticeably, and the latter (D+) allows the car to roll without hindrance. Go downhill, and it's possible to control the car's pace using just the paddles on the steering wheel.

So what's it like?

Quiet. Smooth. Punchy. And... just like a B-Class. This was the desired effect. Remember we mentioned it was built on the regular production line? Mercedes wants to keep the same build quality as its regular cars in this electric model, and also wants to keep the driver familiar with the ‘normal' combustion engine car layout.

So from standstill the B-ED has great acceleration off the line, overtakes with real ease on the motorway, feels well damped, comfortable, and overall, confident. The noise suppression is commendable in the cabin - with barely any train-type whirring - though you do have to watch out for that rather aggressive regenerative braking in D- mode.

The steering - remapped to cope with the revised weight distribution - isn't the best, and felt a tad gluey just off centre, but otherwise it's all standard B-Class fare. Nice.

Lovely but...

We're guessing pricey. Mercedes told us the mighty BMW i3's price was a good indicator (over £30k). When we asked about that car, Merc reckoned consumers aren't ready for a ‘standalone' electric car. Hence why this B-Class has been built to look and act like a B-Class.

With so few customers picking up electric cars, it's not worth Merc investing loads of money, it says. When you lot start buying them in droves, then you can expect a Mercedes ‘standalone' electric car; one designed from the ground up to be electric, just like the BMW.

But the B-Class ED is a good car, well built, with a solid drivetrain. It just needs a sensible pricetag. We'll wait until the final production model is revealed to find out just how much.

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