Why does a light electric car sometimes consume more than a heavy one

Why does a heavier electric car consume less electricity than a lighter electric car? The answer isn’t clear, but a YouTuber disassembled a Tesla Model S Plaid to significantly reduce its weight and increase its performance. Not everything went as planned…

(Electric) cars are often specified by weight. In question, energy consumption (either gasoline or electricity) that increases with the weight of the vehicle. Particularly for this reason, France and other countries have adopted a weight penalty. And we must not forget that the weight of the car also increases the amount of materials needed for its production. This then mechanically increases contamination during the production phase.

but Weight is really a problem for carsMore specifically electric cars? Can we think of other ways to reduce the energy consumption of an electric vehicle? Well, specifically, Youtubeur delivered an amazing experience to say the least, which brings a little water to our problem mill.

Tesla loses 300 kg, what do you give?

on YouTube channel Boost Boys, youtubeur made a completely improbable video. He disassembled a 1,020-hp Tesla Model S Plaid to lighten it as much as possible. Thus he removed the hood, trunk, doors, windows, seats, and a whole host of unnecessary furniture and accessories to drive it. This made it possible to pass The weight of the electric vehicle is only from 2100kg to 1800kg on the scale.

Its goal: to reduce as much time as possible to achieve acceleration from 0 to 60 mph (about 96 km/h). Originally, the American car only took 2.2 seconds in this exercise. The YouTuber measured 2.35 seconds in his original electric car. On the 1.8-tonne version, the measurement is… 2.43 seconds. However, the man indicated in the comments that he managed to concede 2.31 seconds a few hours after posting his video.

However, this experience allows us to draw some conclusions, and not only about the performance of a light or heavy vehicle. The first conclusion is obvious and common for many years in motorsport: yes, A lighter vehicle is more efficient. But does it really consume less energy?

Vehicle consumption relative to its weight

This second question is more sensitive. First, one might be inclined to answer in the affirmative: A lighter car (electric or not) necessarily consumes less energy than a heavier one. But we must not forget an essential element: aerodynamics.

During his first tests with the “naked” car, the YouTuber fared less well than with the heavier car. Then the observers saw an obvious reason for this: Air resistance increased Due to the lack of windows, trunk and hood. A second test that makes it possible to do a better job than the car at its original weight deals a blow to this interpretation.

But as we mentioned in our profile on the car’s aerodynamic drag coefficient (Cx), Car consumption at high speeds is primarily related to aerodynamics. On the contrary, at lower speeds, the vehicle’s consumption is more related to its weight.

Light car or air car?

in other words, A light car that reduces fuel consumption in the city (but also pollution during its production phase), whileAn aerodynamic car that reduces fuel consumption on highways. Do you want the best of both worlds? It is a light and aerodynamic car, which highlights both of these features.

But be careful, because a light car, with unfavorable aerodynamics, can expend more energy at high speeds than a heavy, aerodynamic car. Why create a penalty (or bonus) related to weight..and aerodynamics?

We can take for example Volkswagen ID. Buzz and Mercedes EQS. The German sedan (2.5 tons) weighs almost the same as the electric van (2.5 tons) within a few kilograms, but its consumption is irrelevant.

Mercedes declared a theoretical consumption of 17.2 kWh/100 km on the WLTP mixed cycle versus 20.8 kWh/100 km for the Volkswagen Van. With a Cx of 0.2 for the first versus 0.285 for the second. Here is proof of that Aerodynamics is very important in consumption.

Lighter electric cars in the future?

The good news is that manufacturers want to reduce the weight of the cars, while improving the aerodynamics. We can cite the head of Renault, who wants small batteries with light and compact cars like the electric R5, or even Ford, who wants to design his own SUV like the TGV, with aerodynamic shape and weight.

The manufacturers’ goal is to reduce energy consumption so that they can fit smaller batteries into their electric vehicles. With, as a consequence, a decrease in the cost of production, and therefore a decrease in prices for the consumer, or an increase in margins for investors.

Moreover, in a recent study, Transport and the environment declares that “Reducing battery size enabled by smaller EV manufacturing is the most effective way to reduce metal demand (-19 to -23%)Going forward, the NGOIt calls for policies to encourage the production and launch of affordable entry-level small electric cars, the adoption of innovative battery chemistries and the limitation of solo trips. These measures will reduce the demand for major metals (lithium, nickel, cobalt and manganese) by 36-49%.“.

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