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.
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.