Electric car manufacturers and driving range claim accuracy

Nissan is facing a public relations problem due to battery capacity loss in the Nissan Leaf, and diminished driving range. While the issue is a rapid loss of driving range for Leaf owners in hot climates, a part of the problem is that Nissan claims the Leaf has a 100 mile electric driving range, when the EPA certified driving range is 73 miles. This makes one ponder the value of truth in advertising laws, but it turns out Nissan is not the only automaker doing this.

How are the automakers who manufacture all electric or plug-in electric vehicles doing?

Chevy Volt: The EPA rates the 2013 Volt for 38 miles electric driving range, and GM advertises it with a 38 mile driving range. The Volt also has a gasoline engine that acts as a generator to recharge the battery pack.

Coda: The Coda website repeatedly says "125 miles driving range" where the EPA certified range is 88 miles. The website does have a footnote explaining that "125 miles" is by the LA4 driving cycle, and then the footnote goes on to explain how the EPA arrived at the 88 miles range number.

Ford Focus Electric: Ford doesn't say much, on its website, about the range of this electric car but in the FAQ does have a statement implying the driving range is 100 miles. The EPA certified driving range is 76 miles.

Mitsubishi i-MiEV: Mitsubishi's website says 62 mile range, and the EPA certified range is 62 miles.

Nissan Leaf: In the past Nissan has described the Leaf as having a 100 mile range, but today the Nissan USA website says "73 miles under the EPA MPG derived 2 cycle test". On the Drive Nissan Leaf website (drivenissanleaf.com) a page invites you to see, on the map, how far "100 miles" can take you. The EPA certified driving range is 73 miles.

Tesla Motors: The main page for the Tesla Model S claims a 300 miles driving range per charge, when driven at 55 miles/hr. But dig further into the Tesla website, you keep seeing the "300 miles driving range at 55 miles per hour" claim. However, the EPA certified driving range is 265 miles.

What's going on here? And, how can the automakers advertise one value for driving range, when the EPA certification is a very different value? While the answer to the second question will be difficult to come by, the first question has a very simple answer.

Back in June when Tesla announced the EPA certified electric driving range of 265 miles, the company wrote a pair of long blog posts explaining the EPA testing procedures. All along Tesla has had a of offering the Tesla Model S with a 300 mile electric driving range. In the first blog post Tesla explained that, by the company's range testing, the Model S had exceeded expectations and had a 320 mile electric driving range. In the second blog post, however, results of the EPA certification had come in with a 265 mile electric driving range, and along with this was an explanation of why there was such a huge gap between the 320 mile and 265 mile ranges. Fact is that when Tesla announced the 320 mile range number, they also predicted a 265 mile range certification from the EPA. The reason why is changes in the test procedures used by the EPA.

The old EPA procedure is a 2-cycle test carried out at a 75 degrees Fahrenheit ambient temperature, with varying speeds and accelerations at speeds up to 60 miles/hr, that is not representative of real world driving. The new EPA procedure is a 5-cycle test, with tests in cold weather, and at highway speeds, which Tesla describes as more accurately reflecting real world driving.

This is one source of differences between manufacturer range claims and EPA certified electric driving range. But, that's not the only source of differences.

In Coda's case the "125 mile" electric driving range claim is based on the LA4 test cycle. The LA4 cycle was designed by the EPA to emulate, on a dynamometer, city driving and the majority of driving speeds are under 50 miles/hr. The EPA has other test cycles that emulate other driving scenarios, such as the US06 cycle that is more similar to highway driving.

The purpose of EPA certification of fuel efficiency and driving range is to give us highly credible numbers with which to compare vehicles. But as we see, the automakers do not always play along. With the Nissan Leaf battery capacity loss fiasco currently underway, we see well intentioned Leaf owners who have grown angry with Nissan, and a part of the displeasure is the difference between the "100 mile" claim the company has made in the past, the "73 mile" EPA certified range, and the diminished electric driving range many are getting today.