Let us know if you can figure it out
Some things that we learned in grade school apparently don’t work in the real world. Like basic math for instance. We decided to demystify the confusing EPA mileage range assigned to various manufacturer’s electric vehicles (EVs) only to be slapped down by yet another confusing government process.
Let’s start with the Nissan LEAF, as that is the vehicle with which we are primarily concerned. According to Nissan, a LEAF owner can expect to go 100 miles on a full charge. We know this not to be a reasonable expectation, as Nissan bases their claim on the EPA’s LA4 test cycle – which has an average speed of under 20 miles per hour with a distance traveled of just over 7 miles. Not really representative of the typical driver in the U.S., and we are not really sure how Nissan can even make this claim based on that test. But back to the EPA.
The EPA’s fuel economy portion of the LEAF’s window sticker claims a range of 73 miles – one that we find to be actually very close to what many might reasonably expect to achieve, based on a variety of driving conditions, speeds, and climate. How they obtain this number is where the black magic starts to make itself known.
On the EPA’s fuel economy label applied to the LEAF, they say that it needs 34 kilowatt hours of electricity to travel 100 miles. So, in order to get their estimated range, just do the math. The LEAF has a 24 kilowatt hour battery – 24 divided by 34 equals .71. So, based on this, the LEAF should go 71 miles. But the EPA says it will actually go 73. So one might assume that there might be some rounding involved somewhere along the way to account for the two mile difference. But let’s take a look at the other three vehicles listed on the EPA’s web site.
Ford Focus Electric uses 32 kilowatt hours to go 100 miles. It has a battery capacity of 25 kilowatt hours. 25 divided by 32 equals .78. Based on this one would expect the Focus to travel 78 miles. The EPA says it has a range of 76. Here again we are off by a couple of miles, but in the other direction.
The Coda is not very efficient and uses 46 kilowatt hours to travel the same 100 miles, but Coda has the largest battery here – 31 kilowatt hours. The math would project a range of 67 miles, but the EPA says that it will travel 88. Way beyond a rounding error.
Finally, the Mitsubishi i is the most efficient of the four evaluated here using only 30 kilowatt hours per 100 miles, but it also has the smallest battery pack – 16 kilowatt hours, or just more than half of that found in the Coda. Math would say you could drive it 53 miles. The EPA says you can go 62.
Clearly, we don’t understand grade school math. Either that, or we don’t understand the EPA’s methodology. The EPA is using some basis other than the number of kilowatt hours to travel 100 miles to determine overall vehicle range. If that is the case, why are they even putting the kilowatt hours per 100 mile statistic on the car? Just another mystery of life to ponder.