It’s a given that cold weather plays a part in reducing EV range, now a new test shows just how much of an effect it has.

When the mercury drops, the usable power of a battery drops with it. The low temperature slows down the chemical reaction inside the battery, producing less current and causing the battery to drain more quickly.

To add insult to injury, cold weather increases battery demand as well. When the car is cold, you’re cold. That means use of the power-hungry electric heater, rear defroster, windshield wipers, and even more use of the headlights in the dark of winter.

German car magazine AutoBild ran a test to see how much the range of eight EVs was affected by the cold.

The test was an 89 mile drive with an outside temperature of 41 degrees. Cold, but still not below freezing. The cars all started with a full battery and preheated interiors.

The drive included 26.7 miles (43 km) of highway, 11.2 miles (18 km) of city, and 50.8 miles (82 km) of rural driving. The total was 88.7 miles (143 km). The climate control in each car was set to 70 degrees, the low beams were one, and seat heating was allowed for a maximum of 20 minutes.

The eight cars entered were the Volkswagen e-up and e-Golf, Smart ForTwo ED, Nissan e-NV200 van, Kia Soul EV, Hyundai Ioniq Electric, Renault Zoe, and Opel Ampera-e (Chevrolet Bolt EV twin). All of the cars had a range of at least 100 miles on the optimistic NEDC drive cycle.

Of the eight, three didn’t finish.

SEE ALSO: Improving an EV’s Cabin Heating System

The VW e-up made it just 50 miles from its 18.7 kilowatt-hour battery. The Smart made it 52 miles, and the Nissan e-NV200 van managed 63 miles.

The rest of the cars made it to the end of the test but suffered from a big drop over the expected range. At the end of the test, AutoBild recorded distance completed and the remaining range according to each vehicle’s computer to give a total cold range.

The Soul EV made it 104 miles (167 km) of an expected 155 (250 km). Hyundai Ioniq was the most efficient, with a computer indicated range of 119 miles (192 km) from the 28 kWh battery. That’s 14.6 kWh during the test. Expected range was 174 miles (280km). The e-Golf got 129 miles (208 km) from a 186 mile (300 km) expected, the Zoe got 151 miles (244 km) from 248 miles (400 km)expected, and the first place Ampera-e which had a range of 169 miles (273 km)from an expected 322 (520 km)

The reason for the Ioniq’s efficiency win comes down to the heater. The Ioniq uses a heat pump, like you might have on the outside of your house. It delivers hot or cold air very efficiently. Most of the rest use a resistive heater that works like electric baseboard heaters. They produce lots of heat but use lots of electricity to do it, cutting range even more.

Missing from the test are the Nissan Leaf, BMW i3, and anything from Tesla. But those vehicles are all affected by the cold, and will see a reduction in range. The Leaf’s heat pump and Tesla’s inverter heat exchanger would likely put them close to the Ioniq in terms of efficiency.

                        Car  NEDC Range  Test Range  kWh/100 miles
Volkswagen e-up (18.7 kWh) 100 49.0 37.92
Smart ForTwo Electric Drive (17.6 kWh) 100 52.1 33.6
Nissan e-NV200 Evalia (24kWh) 105 62.6 38.08
Kia Soul EV (30 kWh) 155 103.5 28.8
Hyundai IONIQ Electric (28 kWh) 174 119.0 23.36
Volkswagen e-Golf (35.8 kWh) 186 129.0 27.52
Renault Zoe (41 kWh) 151 151.3 26.88
Opel Ampera-e (60 kWh) 169 169.3 35.2