It was the end of 2020, GMC presented the new Hummer, converted to electric. A significant change for what is still considered one of the most polluting vehicles in the world. Especially its first generation, the H1, with Diesel engines of more than 6 liters of displacement to move a machine of almost 3 tons, with a consumption that can exceed 30 liters per 100 kilometers. But the electric version is no exception to the Hummer philosophy: big, heavy, sweet.
1.3 ton battery
At the time of its presentation, some details, such as the size of the battery, had not been communicated. Although the commercialization of this electric Hummer will begin in the United States, we know that the pack has a useful capacity of 212kWh, out of a total capacity of 247kWh. Not too much to move a vehicle of 5.50 meters and more than 4 tons with a power of 1000 horsepower. A battery capacity that remains exceptional: few cars currently offer battery packs of more than 100 kWh.
And rightly so, a battery of such capacities may seem attractive to increase autonomy. But it will also penalize it, with a weight to carry that will trigger consumption. This is the balance that manufacturers must find between maximum autonomy and daily or frequent use, with a small battery that has the advantage, in addition to its low weight, of being recharged more quickly.
On the scale, the Hummer’s battery weighs 1.3 tons, or more than a quarter of the vehicle’s total curb weight: 4.1 tons.
Consumption in “MPGe”, explanations
Another fact that has just been reported by the EPA, the US environmental protection agency: the official consumption figures for this Hummer, estimated at 53MPGe in combined consumption. A figure that would be disastrous at first glance, although it already requires understanding what these MPGe represent.
These MPGe can be translated into “miles per gallon of gasoline equivalent”, a unit of measurement used in the United States for electric cars and plug-in hybrids to more easily compare with the consumption of thermal vehicles, expressed in “Miles per Gallon”. (mpg).
The MPG are difficult to interpret when seen from Europe: clearly, they allow us to know how many miles (and therefore kilometers, where 1 mile = 1.6 kilometers) can be covered with a gallon of gasoline (about 3.8 liters).
It is also the inverse reasoning to our current way of expressing consumption, in liters per 100 kilometers, which gives the amount of fuel needed (or in electric the amount of electricity, in kWh) to cover this distance.
Unlike liters or kWh per 100 kilometers, the lower the MPGe value, the higher your consumption. The 53 MPGe score therefore represents the worst score for an electric car. With 1 gallon of gasoline equivalent, you could drive 53 miles.
Compared to the Hummer, the best performance is provided by the Tesla Model 3, with 132MPGe. Logic for a “small” sedan (by American standards). If we take the “large” electric SUVs (with European references, 5 meters long and approximately 2.5 tons), the Tesla Model X shows a score of 102 MPGe and a BMW iX, between 76 and 86 MPGe.
More efficient electrical systems… even the Hummer
The idea of the MPGe is still to be able to compare it with the consumption of a thermal car. It is also a way of remembering the great efficiency of electric motors in transmitting energy to the wheels, where gasoline and diesel engines lose a lot of energy, which is materialized in particular through the heat and friction generated during combustion.
Energy efficiency, that is, the amount of energy actually transmitted to the wheels compared to that contained in the fuel, is around 20%, compared to 80% for electric cars, which are much easier to use.
Thus, we find fuel economy scores worse than the Hummer’s 53 MPGe for much less imposing plug-in hybrids: a Porsche Cayenne e-hybrid shows a 46 MPGe score.
It may also be interesting to convert the MPGe into liters per 100 kilometers: in thermal equivalent, the Tesla Model 3 would thus consume 1.78 liters per 100 kilometers. A surprising figure, but one that represents a new example of the best performance of electric motors, especially in the champion of electricity consumption.
The MPGe, established by the US agency EPA, thus sets the relationship 1 gallon of gasoline = 33.7 kWh. That is, a thermal car would only need a tank of 7.6 liters of gasoline (2 gallons) to drive as much as an electric car with a battery of almost 70 kWh, a long-range Tesla Model Y, for example.
For the electric Hummer, consumption would therefore amount to… less than 5 liters per 100 kilometers. A clear advance, in a certain sense, compared to the more than 20 liters per 100 of previous thermal generations.
Much Less Greedy Alternatives
We are still talking about energy efficiency here. The idea may also be to not necessarily use a vehicle of more than 4 tons on a daily basis without “relevant” use. The electric version of Ford’s best-selling pickup, the F-150 Lightning, for example, boasts 70 MPGe, with dimensions even greater than those of a Hummer (5.91 meters long), but with more power, a ton less on the scale.
For buyers of an electric Hummer, of more than 100,000 dollars, it is not certain that this argument of excessive consumption reduces the attractiveness for this type of vehicle, underlines the specialized American site The Drive. Even with its consumption of 40 kWh per 100 kilometers, its enormous battery gives it a theoretical range of 530 kilometers, the “sweet spot” that potential customers will especially look at.
“When there are vehicles like the Rivian R1S, which offer similar features and off-road capabilities with greater efficiency, the Hummer seems especially gluttonous. Some things never change,” concludes the article in the American media.
Let’s see what a certain Tesla Cybertruck will also offer. The next highly anticipated pick-up of the American brand with a very atypical design, would be approaching production, without much being known at the moment about its battery and its consumption.
Source: BFM TV
