- A UK-based publication tested the range of three different EVs in extreme heat in southern Spain.
- The peak temperature during the drive was 111°F (44°C) and the cars were driven at highway speed.
- All vehicles saw a significant gap between their claimed and real-world range, but the Tesla had the biggest difference.
Electric vehicles have a somewhat narrow window of ideal temperature where they operate at their most efficient. This is dictated by their lithium-ion battery packs, which are happiest at between 68°F and 77°F (20°C and 25°C), depending on their chemistry, and an EV’s range will take a noticeable dive if the ambient temperature drifts too far from this ideal window.
We’ve seen many tests looking at what effects very low temperatures have on EV range, and in extreme winter conditions with heating on inside the cabin and open-road driving, an EV will struggle to go much further than half its claimed range. But what happens in extreme heat, with temperatures exceeding 104°F (40°C) and even going up to 111°F (44°C)?
What Car? wanted to find out, so it brought three different EVs to the South of Spain, which is one of Europe’s hottest regions, to see how their range is affected. The cheapest was a Citroen e-C3, which had a small air-cooled 44-kilowatt-hour battery, giving it a range of 199 miles (320 km) on the WLTP test cycle.
Next was a Kia EV3 with the long-range 81.4 kWh battery, granting it a WLTP range of 362 miles (582 km). The third car chosen for the test was a Tesla Model 3 Long Range dual-motor, whose 80 kWh battery pack gives it a claimed maximum range of 436 miles (702 km). Both the Kia and Tesla have a liquid thermal management system for their batteries as well as heat pumps.
For the test, the three cars were driven at highway speeds, which isn’t where EVs are at their most efficient, and the compound effect of the higher speed and the extreme outside temperature had a dramatic impact on their range. All three were way off their claimed range ratings, similarly to how they would have suffered in extreme cold.
They didn’t drive the vehicles until they died, although the e-C3 was the closest to running out, as it had to drive more after trying to charge at a non-functional station. It was calculated that it would have done 142 miles before running out, which is 28.7% less than advertised, due to the worst efficiency rating of the entire group: just 2.7 miles/kWh.
The Kia EV3 pulled in to charge with roughly 10% left in its battery and would have theoretically been able to cover 246 miles before running out, using 2.9 miles/kWh on average. That’s a 32% difference compared to its official claimed range, but it’s not the worst result of the test.
The Tesla was around 44% off its official range claim with a theoretical maximum range of 244 miles, so less than the Kia. It had the group’s best efficiency at 3 miles/kWh, but the range drop was significant.
Charging the three vehicles in the same scorching heat revealed something surprising: both the Kia and Tesla didn’t seem especially affected by the high temperature, and both charged relatively quickly and came close to their official 10% to 80% fast charging times. The Model 3 was charged from 9% to 80% in 32 minutes (not far off its official 27-minute claim), while the Kia went from 10% to 80% in 31 minutes, just 3 minutes off its claimed time.
The Citroen, with its more rudimentary battery thermal management system, was plugged into a 50 kWh charger that provided half of its peak charging power (because the higher-powered charger didn’t work and they had to look for plan B). However, it only charged at a maximum of 38 kW, taking 74 minutes to get from 3% to 80%.
This test is definitely eloquent and well worth doing, and it shows the true impact driving through such high heat has on EV range. The journalists who performed the test mentioned that the Tesla’s full-length glass roof with cover had them running the air conditioning on a higher setting to keep the cabin cool, and that this made a bigger impact on the final range result than in the other two cars.
