What is the difference in consumption in the summer?

Temperature plays a role in the autonomy of an electric vehicle. For the assessment, we pass Renault Megane e-Tech on our test bench.

To assess fuel consumption in real conditions of use, we have developed the superior tests for clean cars. The idea: to review the cars of the moment on the same roads and with the same setup and driving protocol for each, in order to establish a hierarchy and points of comparison.

But an electric vehicle’s consumption, and thus its range, is very sensitive to various factors and can vary rapidly. Especially because of the outside temperature. We’re aware of this, and so are you, but there’s a limit to our paranormal testing: we can’t test all cars at the same time, in the same weather conditions.

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Despite our strict protocol, where the air conditioning is always set between 20°C and 22°C and the vehicle is heated prior to testing, differences may exist. But in what proportions? As long as we have the Renault Megane e-Tech EV60 again, we’ve decided to put the lid back on the model ring to discover its summer autonomy and the differences that might exist.

Renault Megane electronic technology range: 335 km in cold weather

Brief summary of the facts. It was the Renault Megane e-tech car that had the honor of opening our Supertest division. More precisely, the EV60 Optimum Charge version, which was checked at the beginning of March. At the time, we measured the electrical pressure at an outside temperature of 9°C, with the air conditioning set to automatic at 20°C.

At the end of a completely mixed loop conducted in both directions, the combined electricity recognized an average consumption of 17.9 kWh / 100 km. A value that allows it, in these conditions, to offer up to 335 kilometers of autonomy with its battery of 60 kWh of net capacity.

Mixed autonomy – 9 ° C ext.
road .highway town sum
Negatives. Average A/R (kWh/100 km) 16.9 20.5 16.4 17.9
Total theoretical autonomy (km) 355 292 365 335

This new model we were able to try is almost identical. It’s more refined than the Techno version, but with the same hardware as the winter-tested Iconic version thanks to optional packages. The weight difference, which is not even shown in the datasheet, should have no effect. It’s also based on the same 20-inch rims as the Goodyear EfficientGrip Performance Electric engine.

Warming up using the same procedure and with the air conditioning set at 20°C, the new Megane has been driven on the same roads at 24°C now. That’s a difference of 15 degrees Celsius compared to our first test, and now in the best conditions. Note also that we also chose to drive in the dark night hours, in order to develop at the lowest point in the temperature curve, but also to avoid the influence of the sun, which could lead to the automatic air conditioning operation a difficult test.

Autonomy in summer: 384 km

The differences in consumption with the current weather were quickly felt. At the end of this episode, the summer Megane recorded an average consumption of 15.6 kW / 100 km, a decrease of 12.85% compared to winter consumption. With a 60 kWh battery, this corresponds to an average range of 384 km, or 14.63% better than the previous measurement.

There are several factors that affect the range in winter. The first, but not least, relates to different thermal needs, both 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 effect on the consumption here. But the ambient air temperature is optimal for it, operating in its optimal thermal range.

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Against all odds, he’s on the fast track where the difference is least felt. However, this is where the density of the air can have the greatest impact. When the air is denser in winter, it takes more energy from the car to move forward at a certain speed. According to our findings, which will be the subject of a future topic in our columns, the difference is more pronounced at 130 km/h than at 110 km/h, the specific average speed of the mixed loop.

Finally, in terms of recharging, we didn’t notice any significant improvements in downtime to go from 10 to 80%. In the best case, we were able to obtain a curve with barely higher powers of 4-5 kW at an equivalent load rate, allowing, at best, to save 1 minute of total time: the recharge exercise was increased from 37 to 36 minutes, with 128 kW of peak power up to 15% SoC. Nothing new in the tropics when the car has already been driven.

Mixed autonomy – 24 ° C ext.
road .highway town sum
Negatives. Average A/R (kWh/100 km) 14.6 17.9 14.2 15.6
Total theoretical autonomy (km) 411 335 423 384

Gain 15% autonomy with 15°C more

Failure to take precautions regarding passenger compartment temperature before hitting the road in winter can lead to an explosion in fuel consumption. This is especially true on short daily trips, where the “fixed cost” of the heating system significantly affects consumption. It is recognized that independence can drop by 25% to 30% between the two seasons without taking special precautions. And the opposite is also true: in summer, it is preferable to turn on the air conditioning before setting off (and this also serves the convenience of users) and be sure to park your car in the shade, otherwise open the windows to ventilate the air. Cab. The air conditioning effort will be lower.

By taking care of the preconditioning of the passenger compartment, the difference in autonomy between summer and winter is close to 13%, according to our measurement base and with Renault Megane e-Tech. This value is not an exact science (like all measurements outside the lab, in fact), and it’s also hard to make a rule with one measurement (we’ll repeat the exercise with other models), but it does make it possible to create a first one.

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Why does the range of electric cars decrease in the winter?

In short, to find out the consumption in cold temperatures, you can multiply the value recorded in summer by 1.15. Using the same coefficient, you can thus determine the independence of winter by multiplying the independence of summer by 0.87. Note that for the inverse calculation (from winter to summer), you just have to reverse the coefficients of the multiplier (0.87 for depreciation, 1.15 for independence).

Also, in order to highlight the differences in consumption according to temperature, we will not fail to run Renault Megane e-Tech again according to the same protocol with cooler temperatures, close to 0 ° C. See you in January 2023.

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