The temperature has a role in the autonomy of an electric car. To take stock, we pass a Renault Megane e-Tech on our test bench.
To take stock of fuel consumption in real conditions of use, we have developed Clean Automobile Supertests. The idea: to review the cars of the moment on the same roads and with the same preparation and driving protocol for each of them, in order to establish a hierarchy and points of comparison.
But the consumption of an electric car, and therefore its range, is very sensitive to different factors and can vary quickly. Especially because of the outside temperature. We are aware of this, as are you, but there is the limit of our Supertest: we cannot test all the cars at the same time, with the same weather conditions.
Renault Megane e-Tech test: consumption, autonomy and measured performance of our Supertest
Despite our strict protocol, with in particular air conditioning always set between 20°C and 22°C and warming up the car before testing, variations may exist. But in what proportions? As long as we have a Renault Megane e-Tech EV60 again, we have decided to put the cover back on our typical loop to discover its summer autonomy and the differences that may exist.
Renault Megane e-Tech range: 335 km in cold weather
Brief summary of the facts. It was the Renault Megane e-Tech which had the honor of inaugurating our Supertest section. And more precisely an EV60 Optimum Charge copy, screened at the very beginning of March. At that time, we measured the electric compact at an outside temperature of 9°C, with air conditioning set to Auto mode at 20°C.
At the end of a perfectly mixed loop carried out in both directions, the compact electric then admitted an average consumption of 17.9 kWh / 100 km. A value allowing it to offer, in these conditions, up to 335 km of autonomy with its battery of 60 kWh of net capacity.
|Conso. average A/R (kWh/100 km)||16,9||20,5||16,4||17,9|
|Theoretical total autonomy (km)||355||292||365||335|
This new model that we were able to try is almost identical. It is more exactly a Techno version, but with the same equipment as the Iconic version tested in winter thanks to the optional packs. The weight difference, which does not even appear on the data sheet, should have no influence. It is also based on the same 20-inch rims shod in Goodyear EfficientGrip Performance Electric Drive.
Warming up using the same procedure and with air conditioning set at 20°C, this new Megane has therefore been driven on the same roads at a temperature of 24°C now. That’s a 15°C difference compared to our first test, and now in optimal conditions. Also, note that we also made the choice to drive in the dark hours of the night, in order to evolve at the lowest point in the temperature curve, but also to avoid the effect of the sun, which could put the automatic air conditioning on tough test.
Autonomy in summer: 384 km
The differences in consumption were quickly felt with the current weather. At the end of this loop, the summer Mégane recorded an average consumption of 15.6 kWh/100 km, a drop of 12.85% compared to winter consumption. With the 60 kWh battery, this corresponds to an average range of 384 km, or 14.63% better than our previous measurement.
Several factors affect range in winter. The first, and not the least, is related to the different thermal needs, whether for passenger comfort, but also in terms of battery cooling. Since the air conditioning is set to the same temperature, only the thermal management of the battery can have an influence on consumption here. But the ambient air temperature is ideal for it, which operates in its optimal thermal range.
Renault Megane e-Tech test: charging and travel times from our Supertest
Against all odds, it’s on the fast track where the difference is least felt. Yet this is where air density can have the greatest influence. The air being denser in winter, it demands more energy from the car to move forward at a given speed. According to our findings, which will be the subject of a future subject in our columns, the difference is however more marked at 130 km/h than at 110 km/h, the average speed defined for our mixed loop.
Finally, on the recharging side, we have not noticed any significant improvements in downtime to go from 10 to 80%. In the best of cases, we were able to obtain a curve with powers barely 4 to 5 kW higher at an equivalent load rate, allowing, at best, to save one minute on the total time: the recharging exercise is increased from 37 to 36 minutes, with still 128 kW of peak power up to 15% SoC. Nothing new in the tropics when the car has already been driven.
|Conso. average A/R (kWh/100 km)||14,6||17,9||14,2||15,6|
|Theoretical total autonomy (km)||411||335||423||384|
A gain of 15% autonomy with 15°C more
Failure to take precautions regarding the temperature of the passenger compartment before hitting the road in winter causes fuel consumption to explode. And this is particularly true on short daily journeys, where the “fixed cost” of the heating system weighs heavily on consumption. It is accepted that autonomy can drop by 25% to 30% between the two seasons without taking special precautions. The opposite is also correct: in summer, prefer to start the air conditioning before setting off (this also serves the comfort of users) and take care to park your car in the shade, otherwise open the windows ajar to ventilate the air. cabin. The effort of the air conditioning will be less.
By taking care to precondition the passenger compartment, the difference in autonomy between summer and winter is close to 13%, according to our measurement base and with the Renault Megane e-Tech. This value is not an exact science (like all measurements outside the laboratory, in fact), and it is also difficult to establish a rule with a single measurement (we will repeat the exercise with other models), but it makes it possible to establish a first scale.
Why is the range of electric cars reduced in winter?
In short, to know the consumption in colder temperatures, you can multiply the value recorded in summer by 1.15. With the same coefficient, you can thus determine the autonomy in winter by multiplying that of summer by 0.87. Note that for the reverse calculation (from winter to summer), you just have to reverse the multiplier coefficients (0.87 for consumption, 1.15 for autonomy).
Also, in order to shed light on the differences in consumption according to the temperatures, we will not fail to run the Renault Megane e-Tech again according to the same protocol with even colder temperatures, close to 0°C. See you in January 2023.