Electric Mini has to lose weight and flaws
COURTESY OF BMW
Peter Gorrie drives the Mini E whose electric bits weigh 260 kg more than the gas engine they replace. It's a BMW experiment to show the potential of a completely electric vehicle.
MUNICH - I pressed the accelerator of the grey and yellow Mini E.
The little car leapt along a pastoral German road. Its front tires squealed, and I felt a brief tug to the left.
Those responses were normal, say the experts at BMW, which owns the once-British brand.
The Mini E is an experiment; diminished by compromises but showing the potential of electric vehicles. It’s a step toward what BMW says will be the “perfect” expression of battery propulsion: a totally new car, temporarily dubbed the MegaCity Vehicle, or MCV, due in 2013.
The company has been delving into electric power since 1970, when it bolted lead-acid batteries into a model called the 1602. That car served mainly as a technology showcase for the 1972 Olympics, held here in BMW’s home city. Several subsequent versions, too, were curiosities, waiting for technology to catch up to concept.
That happened with the advent of lithium-ion batteries, which, last year, the company installed, along with electric motors and controls, in 600 Mini Coopers. Three-quarters of them went to the United States; leased to drivers selected from 1,800 applicants. Most of the rest were sent to Munich, Berlin and Britain.
The company freely admits that, although well received, these vehicles are flawed and not prototypes for mass production. They do, however, offer insights into how electric vehicles perform, what they require and how the MCV will be configured.
To start, the electric bits — mainly the battery — are 260 kilograms heavier than the internal-combustion components they replaced. The battery cells and electric motor were squeezed into whatever space was available. That meant sacrificing the Mini’s rudimentary back seat and the already limited trunk space.
Most of the added weight ended up over the rear wheels — the wrong result for Mini’s front-wheel drive and the main cause of the squeal and tug.
It is fast off the mark, as you’d expect with a 204 hp motor that generates all of its torque right off the bat. But the front end can’t handle all that power, despite attempts to engineer in some fixes.
The MCV — being designed and engineered from scratch — won’t have that weight-distribution problem: Its 96 battery cells will be packaged in a shallow rectangular box below the passenger compartment, dividing the mass equally between front and rear. Since front-wheel drive requires a heavier front end, the obvious conclusion for BMW is that electric cars need rear-wheel drive.
Take your foot off the accelerator and the Mini E’s brake lights come on — a safety measure because deceleration is very abrupt. The feature is called recuperation; a sort of downshift that feeds energy back into the battery, extending its range by up to 20 per cent.
Like the jackrabbit starts, this makes the Mini E fun. But it creates a technical issue. The car can be made to coast, by applying appropriate feathery pressure to the accelerator. While this reduces battery drain, it cuts into recuperation. BMW hasn’t yet calculated how to balance the two styles for optimum efficiency. The MCV will employ recuperation. How much remains to be decided.
Participants in the American test reported the Mini E’s range, about 150 km, satisfied most daily driving — but then, the criteria for selecting them included suitable car habits. Most recharged their vehicles at home, overnight, and their fallback was at work, so public charging stations likely won’t be necessary for years.
Finally, weight is crucial. Without radical improvements in batteries, BMW won’t apply electric power to anything larger than the equivalent of its 3-series. Meanwhile, it says, new materials and construction will cut kilograms and increase safety.
More about that next week.
Travel was provided freelance auto reviewer Peter Gorrie by the automaker.
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