Behind The Scenes: Data Science Case Studies

Behind The Scenes: EV Data for VW ID.4 and Nissan LEAF

Technical Input By
Blake Hough

Written by
Brandon August

February 21, 2024

Ready to get nerdy and dig into some data from the Recurrent team? We share some findings from two cars that are driven by team members: a 2015 Nissan LEAF and a 2021 Volkswagen ID.4.

Efficiency and range are intricately linked, whether we’re talking about EVs or gasoline vehicles. When considering gasoline vehicles, though, range is often not a concern, primarily due to the long median range, the availability of gas stations, and the focus on vehicle efficiency over range. EVs, on the other hand, flip the script. Most consumers are entirely focused on range, ignoring efficiency, which is a significant contributor to EV ownership costs.

Data from energy.gov: https://www.energy.gov/eere/vehicles/articles/fotw-1221-january-17-2022-model-year-2021-all-electric-vehicles-had-median

It is not uncommon to have several battery size choices when purchasing an EV. The 2024 Nissan Leaf, for example, is offered with a 40kWh or 60kWh battery. If we directly compare this to a gasoline vehicle, that would be like being offered multiple gas tank sizes. However, the major difference here is that an EV battery is a significant fraction of total vehicle cost, and gasoline vehicles only come with one gas tank size. More so, the gas tank is not a particularly expensive component.

Does Efficiency Equal Range?

Much like with two gas cars that have different engines, higher efficiency in an EV does not necessarily mean longer range. Some EVs, like the Nissan Leaf, are considered very efficient, with reports of 5+ miles/kWh, as you’ll see below. However, given the small battery size and very specific, efficient body design, the range is limited, preventing wide-spread adoption. On the other hand, some EVs are less efficient, yielding only 2 to 2.5 miles/kWh (e.g. Rivian R1T), but can still travel 300+ miles to a full charge because of a large, resource-intensive battery.

So why are we so obsessed with EV range? To put it simply - conditioning and routine. The average consumer has been driving gasoline vehicles with an average range of 300+ miles for decades, with little to no concern for gas station availability and reliability. Public EV chargers, on the other hand, can be few and far between, and reliability is mixed.

Although news headlines are dominated by stories of EV failing to deliver on their advertised range in poor conditions, EV forums are full of examples of owners reporting efficiencies and ranges far above EPA estimates. In this article, we explore the real-world data from two vehicles that participated in our Geotab data collection study: a 2015 Nissan Leaf S, and a 2021 Volkswagen ID.4 Pro S.

2015 Nissan Leaf S

Vehicle Model Specifications

EPA Range: 84 miles
MPGe: 126 city / 101 highway
Battery: 24 kWh 360V lithium-ion
Efficiency (est.): 3.50 miles/kWh
Curb weight: 3243 lbs

Details for Specific Vehicle Studied ("My Car")

Operational summary:

Data summary:

As of early 2023, the average EV efficiency (based on a sales-weighted average of new EVs) is 3.4 miles/kWh, making the Nissan Leaf an above average efficiency vehicle. These figures are based on EPA-determined efficiency, which often do not align with real-world data, particularly in the case of EVs that are primarily used for commuting and short city driving. The EPA efficiency tests blend city and highway drive conditions, so cars that are used only for short trips may see much higher efficiency. This is especially important for a vehicle with a range of less than 100 miles, as highway driving and long drives (highway driving) reduce efficiency. As a result, we often observe higher than expected efficiencies, sometimes greatly surpassing EPA estimates.

What the Distributions Can Tell Us

You’ll quickly notice that the distribution looks similar for both the cohort and "My Car," with all vehicles operating in the expected range most of the time. For the cohort, the most frequently observed efficiency matches up well with EPA estimates at nearly 3.5 miles/kWh. This implies that the EPA testing protocol is a decent predictor of normal LEAF driving habits.

In the next chart, we look at the real range as a function of EPA range estimates. At 1.0, the observed range and the EPA range are identical. This happens at 84 miles, as listed on the technical sheets. Looking at the entire cohort, we see that the peak of the distribution is at ~0.7, meaning the EPA range is higher than the range we observe.

2021 Volkwagen ID.4 Pro S

Specifications:

EPA Range: 250 miles
MPGe: 104 city / 89 highway
Battery: 82 kWh 240-400V lithium-ion
Efficiency (calculated): 3.05 miles/kWh
Curb weight: 4665 lbs

Details for Specific Vehicle Studied ("My Car")

Operational summary:

Data summary:

Compared to the Leaf, the ID.4 is much larger, heavier, and has a less aerodynamic design - all of which result in lower efficiency numbers compared to the LEAF. However, the battery is much larger, allowing for a much longer range. Additionally, given the improved battery management system and the relatively young age of the ID.4 line, we expect minimal, if any, battery degradation.