As traditional car factories gradually introduce pure electric vehicles, there are more and more electric vehicle advertisements that were not commonly seen in the past but if you read the battery life figures in the advertisements, those somewhat familiar with electric vehicles may have some doubts: Why is the battery life of this car so long? In fact, the details are hidden in the fine print.
When the general public buys an electric vehicle, the most important factor to consider is endurance because they are worried that charging stations are not as common and fast as gas stations, which is called "range anxiety." One of the ways to combat range anxiety is to build charging stations and the other is to develop more powerful batteries or reduce energy consumption and increase vehicle mileage. Both of these methods are time-consuming and expensive. Is there any way to make the vehicle's range look more beautiful?
The answer is: change the testing standard.
This article will introduce the world's current major vehicle energy consumption testing standards in detail. If you do not have 5 minutes to read the full text, here is a quick key formula for you. Take 30% off NEDC battery life, 20% off WLTP, and 10% of EPA. These three test standard battery life and the gap between test results and real world battery life is the above percentages. If you see an electric car with a NEDC standard range of 600 kilometers, multiply by 0.7, and the real range is about 420 kilometers.
What is the difference between these three test standards? The first thing to talk about is NEDC, which is the favorite of manufacturers and the easiest way to test.
NEDC New European Driving Cycle
Do not be deceived by the name, this so-called "new" has actually been developing since the 1970s. The purpose of which is to provide common test specifications for automobile fuel consumption and exhaust gas, not letting the car factory have the final say. In order for a wide variety of vehicles to share the same test basis, the tests must be conducted in a laboratory to remove weather, road conditions, and driving variables.
During the test, the four wheels of the vehicle are placed on a damping roller, there is a huge fan in front to simulate driving wind resistance, and electronic equipment such as air conditioning, audio, headlights or heated steering wheel, and electric massage chair will be turned off throughout the entire process.
NEDC simulates two road conditions: urban and suburban. The maximum speed in an urban area is 50 kilometers/hour, with an average of 18 kilometers/hour; the maximum speed in the suburbs is 120 kilometers/hour, with an average of 62 kilometers/hour. Test mileage is 11 kilometers and the total test time is about 1,180 seconds.
The author does not know how the average person usually drives but if the average speed of a car in front of you is only 18 kilometers/hour, it will definitely drive you crazy. From this test method, it can be seen that NEDC is quite different from an actual driving environment. Of course, the fuel consumption or electric vehicle battery life figures will be more beautiful.
WLTP World harmonized Light-duty vehicles Test Procedure
In the long period from the 1980s to 2010, consumers have become accustomed to the fact that there was a large difference between fuel consumption released by the manufacturer and when actually driving and everyone seems to be too lazy to say anything. Unfortunately, in this automotive company golden age was terminated by the "dieselgate" exhaust fraud incident perpetrated by the Volkswagen Group. The European Union believed that stricter and more credible regulations must be introduced to save the reputation of the automotive industry, so the WLTP specification was developed.
Car owners must know that although the NEDC test standards are still in place, after September 2019, all EU model certifications follow the WLTP specifications and do not accept NEDC.
The vehicle test of the WLTP specification is called WLTC but in order to avoid confusion, the car factory uniformly refers to it as WLTP data. The test methods of WLTP and NEDC are actually very similar with the difference being adjusting several parameters. First of all, the test is divided into four grades according to the ratio of vehicle power to vehicle weight. Generally speaking, the higher the power vehicle weight ratio, the stronger the vehicle performance. According to this classification, different test standards are given to different grades of vehicles.
Simply put, the higher the performance of the car, the higher the speed used in the test. In addition, WLTP has a total test time of 1,800 seconds and a total test distance of up to 23.2 kilometers, all longer than NEDC.
In order to be closer to an actual driving experience, the average speed of WLTP is increased to 46.5 kilometers/hour and the maximum speed can reach 131 kilometers/hour. Most importantly, the WLTP specification greatly increases the ratio of acceleration and deceleration during the test process. Compared with the NEDC test, where the constant speed driving time ratio is 40%, the WLTP test ratio only 3.7%. After all, stop-and-go is closer to a general driving experience.
The strictest US EPA standard
The above two are test standards implemented by the European Union, which are basically universal, but the US Environmental Protection Agency (EPA) has its own system, especially for electric vehicles.
Before the EPA test, the electric vehicle must be fully charged and in place overnight before the test can start. The simulated road conditions are also divided into urban and high-speed. The vehicle is also driven on a roller but the special thing is that the EPA test will make the vehicle run until it runs out of power. Instead of just running a few minutes of calculations.
▲quick comparison system that lets consumers see vehicle energy consumption（Source：EPA）
The worst thing is that after the final data comes out, the EPA will directly multiply the mileage by 0.7 to estimate actual road performance. After all, during the test process, there is less electrical equipment on the car and a less enthusiastic right foot of the car owner. More importantly, there are often low temperatures close to zero in Europe and the United States, which affect the battery life performance, so a 30% discount is reasonable.
Special Mention: Guide to Vehicle Fuel Consumption by Energy Bureau of the Ministry of Economic Affairs of the Republic of China
In addition to these three standards, there are also some other standards for reference such as the Chinese CLTC standard, which is roughly the same as NEDC. The Taiwan Ministry of Economic Affairs Energy Bureau's vehicle fuel consumption guidelines are directly related to Taiwan's consumer rights because no matter which standard the original factory adopts, when vehicles sold in Taiwan are marked with energy consumption, they only need to comply with Taiwan's Ministry of Economic Affairs regulations.
What are the regulations of the Energy Bureau of Taiwan's Ministry of Economic Affairs? After all, Taiwan is a small market country, so the fuel consumption guidelines of the Energy Bureau of the Ministry of Economic Affairs all adopt so-called "EU standards." The interesting point is here. We now know that the EU has two standards, the old NEDC and the new WLTP. What is the "EU standard" that the Energy Administration is talking about?
The answer is: manufacturers decide for themselves. According to the 2021 version of the Vehicle Fuel Consumption Guide, domestic vehicles all use NEDC data and most of the imported car manufacturers also use NEDC, while a few use WLTP data, which is reported according to the model. Since the NEDC numbers are pretty good, why should manufacturers go to the trouble of reporting WLTP data?
Therefore, WLTP data will be used, from mostly high-performance cars and almost all car models report NEDC data to make the fuel consumption look more beautiful.
Conclusion: WLTP works, EPA is too strict
In the end, readers will definitely want to ask, which standard is closer to the truth? Based on actual test drives of electric vehicles, as well as actual measurements of a large number of foreign car owners and YouTubers, for car owners who generally commute and do not have a lead foot, real-world endurance is still close to WLTP data. This is of course also related to the speed limit in Taiwan but according to the subjective experience of actual driving, the WLTP figures are about 85%~95% accurate compared to the driving habits in Taiwan.
EPA data represents a 30% discount on battery life when the car leaves the factory but, in fact, Taiwan is rarely close to zero degrees and low temperature and its highways are not as long as the United States, so the EPA’s numbers in Taiwan are sometimes lower than that of actual driving. Overall, the real cruising range of electric vehicles is roughly between the WLTP and EPA figures for Taiwanese car owners.
However, EPA data is upfront stating that t is provided for reference to the American people and not for foreign countries. Therefore, most car manufacturers will not provide this data. Thus, if Taiwanese consumers want to buy electric vehicles, they will basically only see WLTP or NEDC data. If a car manufacturer only releases NEDC data, the mileage is usually high but test specifications are unusually low. Therefore, the easiest way is to discount the mileage number by 20%, so as not find the gap between expectation and reality is too big and feel uncomfortable after purchase.
In the same field: the energy consumption test of Taiwan scooters, according to the Ministry of Economic Affairs standard, the maximum speed less than 60 kilometers/hour within 600 seconds and 80% of the time lower than 40 kilometers/hour, so as to measure the urban energy efficiency. Then drive 2 kilometers at a constant speed of 50 kilometers/hour and test 3 times to get average fuel consumption, so as to measure the constant speed energy efficiency. The final fuel consumption score is 60% urban energy efficiency plus 40% constant speed energy efficiency to calculate kilometers per liter.
There is no unified specification for the endurance algorithm of electric scooters. According to the Gogoro test standard, a rider with a speed of 30 kilometers/hour and a weight of 63 kg driving on a flat asphalt road with the original tire pressure until the battery runs out produces data that is an amazing 150 kilometers of endurance. Kymco Ionex also adopts this standard, so endurance deviates quite a lot from real situations. According to unreliable experience statistics, battery-swappable electric scooters are currently driven on general roads in Taiwan, with a cruising range of about 45-60 kilometers.
（Image：Mercedes-Benz）
