How to measure the consumption of your electric car?

One of the most important points in an electric car is its consumption, since now there are no more liters of gasoline as it used to be in combustion vehicles. A measurement system that has gone to kw / h, energy efficiency , pure performance…. But how is it measured in this type of vehicle? What techniques do they follow? Is it done the same as with the conventional ones?

Among the factors that make us show whether an electric car compensates us is its consumption, we must find out how much light it uses. And this we are going to know taking into account the different considerations that influence the energy consumption of one or another model. In any case, a certain fact to consider is that it is a more environmentally friendly vehicle, but also more energy efficient speaking than a gasoline or diesel.

The difference in spending with an electric

In fact, the transport sector is considered the last bastion of oil that is slowly languishing. Refineries have begun to adapt to this situation by redesigning their facilities with extensions and improvements to maximize their own production of transportation fuels. Faced with this, the growth of the electrified is increasing, exceeding many of its limits.

The global fleet of electrified vehicles offsets around 100,000 barrels a day of trucking fuel each year, mostly gasoline, according to a report by Bloomberg New Energy Finance. Because, the truth is that the electric car is not the future, but a reality that many people already enjoy.

Thus, the sales of electric vehicles during reached a growth of 30% last year, if it is compared with the same period of 2019. An accumulated that is already making big steps in firm this 2021, and much of the blame lies with this type of electric car that makes, among others, because we can save a good amount of money in its consumption compared to gasoline or diesel. Likewise, it should be mentioned that the measurements of one car and another are quite different.

What is the consumption of an electric car

Finding out how much one of these features is spending can be done in many ways. It is true that any of the models on the market has an application with which to control the energy it consumes. As you have read other times, the purchase price of a 100% electrified may be higher due to the cost of its batteries.

But it is also true that once you have it in the garage, you can forget about oil changes, belts and any other consumable other than the cleaning brushes, the cabin filter and the wheels. To know how these consumptions are governed, you have to pay attention to their measurement, the kilowatt-hours, specifically, the kwh / 100 km . This is the number of kilowatt-hours consumed per 100 kilometers. Instead of using liters every hundred km, the consumption of an electric car is measured in kWh / 100 km. Easy right?

Although we usually focus on autonomy, knowing the car’s consumption will allow us to have a more precise idea about its efficiency. Also to have an estimate of the cost per km traveled, since the lower the consumption, the less money we will spend to travel the same distance. Now, how do you know if a car consumes a lot? What is a low number? This has a lot to do with energy efficiency , a key point in the process of measuring the consumption of an electric car.

Energy efficiency, key

In the first place, the remarkable thing is that these electric ones do not consume fossil fuels, but that does not mean that using them is free. They represent a tremendous savings, but it is not free, of course. In this way, consumption is the most important point to take into account. Without the need for calculations, it is known that electric motors are much more energy efficient than combustion engines.

It is that energy efficiency that will end up telling us how good is the consumption that our electric car will have. This directly influences the origin of the sources from which the electricity is obtained within the generating park, since a thermal power plant can have an efficiency between 35% and 60% and another with 100% renewable sources.

In this way, the conventional gasoline vehicle, with an internal combustion engine, has an overall efficiency of 25% . That is to say; that of the energy of the fuel introduced into the car, only 25% is obtained in the form of mechanical energy for the movement of the wheels, which means that the remaining 75% is wasted.

The reason? Friction within the engine, in traction or the thermodynamic factors that limit performance in internal combustion engines. On the other hand, in other types of vehicles, such as the hybrid (HEV), the introduction of an electric motor, in addition to the conventional one, contributes to the improvement of energy efficiency until reaching levels of 30%.

This is something that becomes very noticeable with the one that is 100% electrified. Here, the estimates show an efficiency that reaches 77% if the electricity that charges the BEV batteries has a fully renewable origin and 42% if the electricity generation mix is ​​based on natural gas. Logically, the plug-in hybrid, the PHEV, since it is a combination of a conventional and electric motor, will have a mixed efficiency between 31-49%, depending on their use, much higher than that of the conventional vehicle or the traditional hybrid.

As measured

When buying a new one, this scale is based on the ratio of kilometers and liters. Depending on the number of liters consumed per 100 km, it can be identified whether it consumes a lot or a little. The problem found in electrified cars is that we are not talking about liters / 100 km, but about kWh / 100 km. The error lies in making an equivalence.

That is to say; which is not the same 5 liters / 100 km to 5 kWh / 100 km. Therefore, regardless of what is considered efficient with gasoline engines, we can not establish an equivalence ratio between liters and kWh. Currently, a consumption that is in the environment of 18 kWh / 100 km is a reasonable consumption, below this figure we will be facing very efficient cars.

The most efficient models currently on the market are around 14 or 15 kWh / 100 km . There are cases like the Hyundai Ioniq that does it in 11-12 kWh / 100 km, but it is not usually the usual trend. Those would be, closely, the best or best figures that this type of car can have today.

At the same time, they can also be considered high consumption when exceeding 20 kWh / 100 km. ¿ And how these measurements are made? Well, hand in hand with the WLTP cycle , which came to the sector a few years ago and almost completely revolutionized it. This is an international protocol that has the purpose of determining the consumption and emissions of each vehicle for its subsequent homologation.

Compulsory to pass the review and approval of this type, it is done by the hand of two mandatory requirements:

  • Fully charged battery . As would the fuel tank of a combustion model, the vehicle is reconnected to the charger, the cable of which is equipped with a meter. This device is the one that measures the total amount of current, and the one that can also detect possible battery power losses during the charging process.
  • Possible energy losses . Once the battery has been charged to 100%, the value marked by the meter is divided by the autonomy figure that has been determined in the test carried out at the bench. The result is an amount, measured in kWh / 100 kilometers, that corresponds to the electricity consumption of a specific model, measurements that have to be repeated with the different diameters of rims and optional equipment.

Factors and levels according to conditions

Once these measurements of consumption for electricity are known, it is important to bear in mind that we will never have the same record in the city as on the road. This is because different parameters and factors enter here that will directly affect the encrypted levels.

And that’s where the costs usually come in. Putting a daytime domestic energy price of 0.158 euros per kW, making 100 kilometers will cost about 2,054 euros . So we can say that driving with an electric car is less than half the cost of a traditional car fuel. That is where factors to consider during our movements come in.

Because it is true that, although we can travel to two different places with a similar route (100 km), the conditions that we will find on the way will not be the same, which does to severely affect consumption levels. For example, on the road, our records may usually be higher. On the other hand, in the city, this tends to normalize (its figures are the ones that most agree with the WLTP homologation cycle).

Town

The city is a great enemy of spending for a combustion engine car. Each braking, each acceleration, each gear change will involve considerable consumption. However, for a vehicle with EV technology, urban traffic is its great ally because the autonomy of an electric car in the city is multiplied.

Put to compare, here we would have data of one euro per 100 km , while the cost of gasoline in an average combustion car can be around seven or eight euros per 100 km. In addition, if you are an urbanite, the great advantage is that you can recharge your vehicle at home, with the savings and convenience that this entails in front of service stations.

Road

If we go to the highway or to longer trips, the truth is that the cost of electrical energy shoots up. So much so that it can increase above 50% percent if it exceeds 120 km / h. In the case of diesel or gasoline, it is generally the opposite. And, as we have seen, the electric car has a much lower consumption in the city than on the highway, unlike those with a combustion engine.

Also, when driving this type of vehicle, we can find factors that make an electric car trigger that expense, and among this is heating . By not having a combustion engine that emits heat, the air conditioner has to operate at a higher range and increases consumption. The same can happen with the heated rear window or other electrical elements that we connect.

by Abdullah Sam
I’m a teacher, researcher and writer. I write about study subjects to improve the learning of college and university students. I write top Quality study notes Mostly, Tech, Games, Education, And Solutions/Tips and Tricks. I am a person who helps students to acquire knowledge, competence or virtue.

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