When choosing an EV, the range is a crucial factor for buyers of electric vehicles. It becomes even more difficult when the actual range of an EV contradicts what is advertised by the company.
Today we are going to look at how the EV range is determined and what are the different standards available for EV range.
Let’s look at them one by one
What Are The Main EV Test Standards
There are mainly 3 mainstream testing standards used by manufacturers worldwide to determine and quantify an electric vehicle’s range.
They are,
- The Environmental Protection Agency (EPA) test
- The Worldwide Harmonised Light Vehicle Test Procedure (WLTP)
- The New European Driving Cycle (NEDC)
While the EPA test is for the United States, the NEDC and WLTP are European standards.
The testing protocols for each are described in their procedure. The common opinion is that the EPA test provides the most accurate value of real-world outcomes for American drivers, whereas the NEDC is generally regarded as the least reliable of the three.
So why do we need different testing standards? Let us see
Why Do EV Range Estimates Differ For US & Europe?
This is because of the difference in the driving style and cycle in Europe and the US. The European driving cycle is majorly focused around cities and U.S drivers spend most of their time in the highways due to the interstate system.
Since most European drivers engage in urban and suburban driving, the NEDC and WLTP base their estimations largely on this kind of driving. Because Americans spend more time on interstates whether commuting to work or taking leisure trips, the EPA places a strong emphasis on highway driving.
How NEDC is Calculated?
To carry out the NEDC test, the EV to be tested is driven on a chassis dynamometer, which replicates the resistance and inertia of driving on a road.
The test comprises 4 phases each of which reflects a distinct driving condition
Urban cycle: The urban cycle combines braking, accelerating, and idle times to mimic driving in urban traffic. This phase makes up around 20% of the whole test distance and is intended to simulate a normal urban driving pattern.
Extra-urban cycle: This type of driving mimics stable speeds with little acceleration or deceleration, much like driving on an open road or highway. This phase makes up over 60% of the whole test distance and is intended to mimic a normal suburban or rural driving pattern.
Constant speed cycle: This cycle mimics travelling a short distance at a steady speed of 90 km/h.
Phase of cold start: This stage imitates starting the car from a cold start and going a short distance.
Using specialised technology, the vehicle’s fuel usage or range is measured throughout the test.
The NEDC was created in Europe in the 1980s and underwent its most recent revision in 1997. This test cycle is not only outdated but it is also seen negatively due to its lab-based methodology, which gathers data in controlled environments instead of real-world driving scenarios.
Now let us look at the WLTP test and learn how it differs from the NEDC
NEDC & WLTP: What Makes Them Different
The NEDC technique is being replaced by the WLTP system, which was unveiled in 2017. The goal of the most recent WLTP processes is to evaluate cars in more realistic scenarios that more closely resemble real-world driving circumstances. Both of them might seem identical since both of them are conducted in labs but the rest of the testing aspects for WLTP are different.
The EV driving range may be estimated using either WLTP or NEDC. However, the WLTP improves upon the NEDC in several ways to produce more precise results. For instance, the WLTP switches from a 20-minute single test cycle to a 30-minute dynamic test cycle. The test cycle contains a greater mix of both urban and non-urban driving, and it increases the distance and number of driving phases.
In comparison to the NEDC, the WLTP tests cars at faster speeds, different shift points, and more realistic temperatures.
Moving on to the American roads.
How Is EV Driving Range Estimated by the EPA?
Estimates produced in the United States are more accurate for actual driving on American roads since the EPA’s testing protocols are more stringent than those of the NEDC and WLTP.
When testing EVs, the EPA frequently employs a process called the multi-cycle test, which calls for fully charging the battery before leaving the car parked overnight.
The EV is placed on a dynamometer the next day by the EPA, which then takes it through a series of steady-state, city, and highway driving cycles until the car runs completely out of charge. Once the batteries have been fully recharged once more, the EPA calculates an estimated driving range.
Apart from the vehicle range, this test also yields a trustworthy estimate of miles per gallon equivalent (MPGe).
EPA v/s WLTP
The findings of real-world testing indicate that electric vehicles have the most accurate EPA ratings. The WLTP range statistics are roughly 11% higher than the EPA range predictions.
For instance, an electric car with a WLTP range of 100 miles (or 100 kilometres) is likely to have an EPA range estimate of about 89 miles (or 89 kilometres), which is 11% shorter than the WLTP requirement.
Not only does EPA provide the most accurate data, but WLTP is the second most reliable standard for estimating an electric vehicle’s true range. Look for EPA and WLTP data to find out the actual range of your prospective electric vehicle.
Is that all? No.. We have only considered Europe and the US but what about the Asian countries?
CLTC: The Chinese Range Test
In the realm of electric vehicles, only Chinese automakers use the NEDC standard to assess the range of their vehicles these days. American automakers use EPA ratings, while European and Japanese automakers rely on the WLTP standard.
However, China has been progressively introducing the CLTC (China Light-Duty Vehicle Test Cycle), a new fuel economy/EV range test technique, in its home market.
Three test stages are included in the new CLTC standard (slow, medium, and rapid driving). The EV has to cover a total distance of approximately 14.5 km throughout the 30-minute testing procedure. One may think of CLTC as the Chinese manufacturers’ WLTP counterpart. Additionally, there are a few noteworthy distinctions between CLTC and WLTP.
CLTC v/s WLTP
CLTC estimations are often greater than WLTP and NEDC range estimates. For instance, when CLTC testing methods were followed, an electric car with a 398 km WLTP and a 484 km NEDC range estimate scored higher range (509 km). This is because the Chinese government intended to develop a new testing protocol that would account for Chinese roads, traffic patterns, and driving behaviours.
Consequently, the Chinese have a more optimistic standard for EV range testing and the more optimistic the tested range the lesser the actual range.
In general, CLTC range values are typically 15–25% more than WLTP. The majority of Chinese EV manufacturers have already begun displaying range information via CLTC.
Modified Indian Driving Cycle (MIDC)
In India, the range of electric cars is evaluated using the MIDC (Modified Indian Driving Cycle) mode. Similar to mileage testing, they are conducted on level grades in suitable weather with the battery fully charged and no other electronics running.
A setting like this one enables the car to operate at its full range. Naturally, the real range is shorter than the certified or stated range.
Conclusion
The point to be noted is that, even though these ranges do help you narrow down EVs that are more fit for your lifestyle, when choosing an EV many other considerations should be taken into account. For instance, you’re likely to find real-world EV ranges that are much lower than even the EPA estimates if you live in a cold climate or drive frequently throughout the winter.
Running power-hungry accessories like air conditioning affects EV range as well, so if you operate these equipment frequently, the figures you see will also be lower than the actual values.
However, if you reside in a temperate climate and your driving habits closely resemble the test which is used to find the range(EPA, WLTP or CLTC), you may also get numbers that are closer to the WLTP ratings or EPA ratings.
