BMW 1 Series ActiveE

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7 October 2011

What is it?

An electric powered version of the BMW 1 Series coupe called the ActiveE. To be produced exclusively in left hand drive in numbers totalling no more than 1100 at BMW’s Leipzig factory.

The hi-tech two door is set to be offered to customers on a two year/31,000 mile lease scheme similar to that undertaken with the earlier Mini E.

Unlike the Mini E, which largely used off-the-shelf electric drive technology, the 1 Series ActiveE has been conceived in close partnership with a series of system suppliers that will also play an important role in the establishment of BMW’s new i brand and its initial i3 and i8 models.

The 1 Series coupe has been heavily modified to accommodate the Active E’s electric drive system. Among the more significant changes is a new crash structure up front and altered transmission tunnel down the middle of the steel floorpan.

Power comes from a brushless electric motor mounted at the rear in the space usually taken up by the differential of the standard 1-series. Produced at BMW’s Dingolfing factory, it produces 170bhp and 184lb ft of torque the moment you depress the throttle – 33bhp less but 24lb ft more than the Mini E’s electric drive system. By comparison, the 118d coupe’s 2.0-litre common rail diesel engine kicks out 143bhp and 221lb ft.

Electrical energy to run the motor is provided by three separate banks of lithium ion batteries. Together they possess an overall capacity of 32kWh and provide a peak current of 400 amps.

The battery cells hail from a joint venture company created by Korean giant Samsung and German based electronics specialist Bosch called SB LiMotive. The so-called control electrics, the brains of the whole system, are located in the boot, which shrinks to just 200-litres.

In a move BMW says was prompted by lessons learnt with the Mini E, the batteries receive liquid cooling to ensure constant performance. Recharging is via a plug-in socket located behind the traditional tank flap. Using the 32 amp charger that BMW offers has part of the 1 Series Active E lease deal, it is claimed to take between four and five hours on a standard 240 volt mains.

Drive is channeled to the rear wheels via a single speed transmission. Oddly given the investment BMW’s i brand has made into lightweight construction technology, the 1 Series ActiveE retains an all-steel bodyshell without any aluminium or carbonfibre. The standard rear bench seat has, however, been exchanged for the same pew as that used by the 1 Series M coupe, which is claimed to save 5kg. Still, kerb weight is put at a portly 1850kg.

What’s it like?

A little underwhelming at first sight owing to the lack of styling changes over the standard 1 Series coupe. You notice a bulge in the bonnet to accommodate the front-mounted battery, a uniquely styled front bumper, spurious lack of tail pipes at the rear and a slightly higher ride height. But besides some distinguishing graphics, that’s about it.

In the driver’s seat, it also feels like any other 1 Series coupe… until you hit the starter button, release the manual handbrake and flick the gear lever into drive.

The delivery of power from the electric motor is silken smooth and terrifically refined. The only hint of its operation is a distant whir under acceleration. On the run, it is the sound of the tyres, rolling across the bitumen, wind roar around the exterior mirrors and the odd ping as stones are flung into the wheel housings that provides the main sensation of speed.

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Like most modern day electric cars, step off performance is strong if not exactly dazzling, owing to the weight. Official claims see the 1 Series ActiveE accelerating to 37mph (60km/h) from standstill in 4.5sec, with 62mph (100km/h) coming up in 9.0sec. Top speed is limited to 87mph to protect the charge of the battery. While the upcoming i3 is set to boast a range of up to 140 miles, the heavier 1 Series ActiveE can travel just 100 miles between recharging of its batteries.

To accumulate as much kinetic energy as possible while on the run, the ActiveE boasts an aggressive recuperation mode similar to that of the Mini E. When the driver backs away from the throttle the electric motor acts as a generator, providing sufficient levels of retardation that you rarely need to rely on more than a fleeting dab of the brakes, upgraded 300mm discs at each corner, at around town speeds. It’s so aggressive, BMW has programmed the brake lights to illuminate when you lift the throttle.

Unlike other recent new electric powered cars, Volkswagen Golf E-Motion included, BMW has decided against providing the zero emission 1 Series with variable, multi-stage energy recuperation.

The high degree of deceleration is a little disconcerting at first, causing your head to rock forward as you enter a phase of trailing throttle. But it quickly becomes second nature to rely more the electric motor than the brakes when approaching a red light to ensure the battery charge and with it the overall range remains as high as possible. The trick to smooth progress in stop/start city traffic is a progressive action as you come off the throttle.

A departure from the Mini E is the so-called EcoPro mode. Activated via a button on the centre console, it alters the throttle mapping to make it less aggressive while reducing the performance of the air conditioner – all in the interests of battery charge.

To tell you the truth, we were a bit surprised by the rear wheel drive 1-series ActiveE’s dynamic properties. Given its weight and 205/55 R16 profile low rolling resistance Bridgestone Turanza ER300 tyres, we didn’t expect it to be any near as entertaining as it is. Granted, it doesn’t match the high standard set by more conventionally powered versions of BMW’s entry level coupe, but by electric car terms it is surprisingly fluid in its actions and displays real poise when pushed through corners.

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Siting heavy items such as the batteries, which alone weigh over 300kg, and electric motor as low as possible helps, of course, leading to a relatively low centre of gravity. But BMW must also be commended for the excellent chassis tuning, which endows the 1 Series ActiveE with genuinely sporting appeal. With well weighted electric steering geared at 2.9 turns-lock-to-lock, it turns in to corners with precision and provides an impressive level of grip before the onset of the standard stability control system.

Despite the raised ride height, a necessary measure owing to the added weight, there is also very little body roll. The ride is characteristically firm, but on the smooth surfaced roads around Munich the suspension – a combination of MacPherson struts at the front and multi-links at the rear - proved to be nicely controlled when faced with uneven bitumen, but we’ll reserve our verdict on ride until we can get onto some more challenging roads. Likewise, the brakes, which possess electric actuation.

Should I buy one?

It’s certainly very well engineered and very convincing to drive. But the question everyone needs to ask themselves when considering an electric car is: how much do I drive on a typical day? If it is below 100 miles, the 1 Series ActiveE could be seen as an alternative to more conventional petrol and diesel engined 1 Series coupe models, although you’ll need to ensure easy access to mains power. You’ll also need to ask yourself if you can live with a car that is compromised in terms of practicality, because of the relatively small boot.

The 1 Series Active E is only available on a limited lease deal and in left-hand drive only. As yet, there’s no official word on when the new zero emission coupe will be pushed in the UK or at what leasing price, although expect to see plenty of them tooling the streets of London as part of BMW’s sponsorship deal with next year’s summer Olympics.