Electric cars can travel up to 19 miles after their range readout hits zero

Electric cars can travel up to 19 miles after their range readouts hit zero, new What Car? research has shown.

Ten of the latest fully electric models were put through a summer range test to see how far they would go in optimum conditions, with the contenders falling between 8.1% and 18.6% short of their official averages.

In each case, though, the figure was helped by the car continuing to run for several miles  after the instrumentation said there was nothing left in the battery. This suggests that range readouts are deliberately programmed to be conservative so that owners have an emergency buffer to help them get to a refuge area or find somewhere else safe to stop.

Of the cars tested, the BMW i4 eDrive40 M Sport went farthest on a charge and had the biggest buffer: 316 miles and 19 miles respectively.

Meanwhile, at the other end of the scale, the Cupra Born had the shortest summer range (219 miles) and the BMW iX3 the smallest emergency buffer (five miles). 

It should be noted that exact emergency buffer figures that we saw should be taken as a guide only, because they were influenced by the point on the test route that each car began to display zero miles remaining.

Three of the cars were also involved in our most recent winter range test, with the BMW iX3 M Sport Pro covering an extra 41 miles in summer, the Kia EV6 RWD GT-Line an extra 50 miles and the Tesla Model Y Long Range an extra 57 miles, giving an indication of how weather extremes can affect electric vehicle performance.

On average, the trio went 49 miles (21.4%) farther in the summer range test, when the air temperature ranged from 24-29deg C, than in winter, when it was 3-7deg C.

Previous research by What Car? found electric cars equipped with a heat pump lose less range when temperatures drop, with the heat pump drawing excess heat from the electric drivetrain and distributing it around the interior of the car through the air conditioning, reducing the strain on the battery. 

The tests were conducted on a closed vehicle proving ground, on a 15-mile route consisting of 2.6 miles of simulated stop-start urban traffic, four miles of steady 50mph driving and eight miles driving at a constant speed of 70mph, to simulate motorway journeys. 

Each of the 10 cars was fully charged and left outside for 15 hours, before being plugged in again to check the batteries were still at 100% for the start of the test. They then had their climate control systems set to 21deg C and were driven until they ran flat, with driver swaps at the end of each circuit, and the cars’ positions also changed to ensure no car was constantly punching a hole in the air to improve aerodynamic efficiency for the others.

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Read the full range test feature >>

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