Getting behind the wheel of an electric vehicle is an experience like no other: clean energy, a quiet ride, and anywhere from 200 to even over 500 miles of range on a single charge. But if you’ve ever driven an EV from a full battery to an empty one, you’ll probably notice the distance you traveled falls far from what you were promised.
If you’re searching for electric vehicles by range, a variety of testing methods can skew the results. And since this ultimately limits how far you can roam and how much you really know about your vehicle, it’s fair to ask just how manufacturers and the EPA can sometimes be so far off the mark.
Below, we’ll look behind the scenes at how EV ranges are estimated, why those estimates might differ from experience, and a few things you should know about how to preserve your battery for as long and as far as possible. Let’s get started.
Let’s clear this one up first: no, EPA EV range estimates, and ranges from several EV manufacturers, are often not reflective of the actual range when you get behind the wheel.
Why? Basically, testing methods used by the EPA and private automakers are either not aligned with modern EV capabilities, or they’re used to inflate range estimates to make some EVs more attractive to buyers.
In fact, Car and Driver found that internal combustion engine (ICE) cars tested had an average fuel efficiency of 4% higher than advertised, whereas EVs’ average range was 12.5% lower than promised. Tesla, which puts its vehicles through a five-cycle testing process, is one of the worst offenders in the latter category, with actual ranges off of advertised ranges by an average of 26%. At the other end of the scale, EVs from Porsche and Mercedes-Benz were the only ones to offer better range than advertised.
The Environmental Protection Agency (EPA) has been testing the fuel economy of new cars in the United States since 1971, just a few months after its creation. The EPA uses the Urban Dynamometer Driving Schedule (UDDS) to determine city mileage, and the Highway Fuel Economy Test Driving Schedule (HWFET) on the highway.
First, an EV under testing is fully charged and left to sit overnight. Then, it’s subjected to the UDDS until the battery is dead. It’s then recharged and subjected to the same process with multiple HWFET tests. Both tests are carried out on a dynamometer, which is something like a treadmill for cars, at around 55 to 65 mph. Since EPA testers know this doesn’t reflect actual road conditions, the readings from these tests are then multiplied by 0.7 and adjusted for highway and city driving conditions to produce the final range estimate.
However, the EPA also offers automakers the option to put new EVs through three extra test cycles, which can significantly boost the resulting range through more readings and, thus, a higher average. This five-cycle test process is how Tesla can promise such high range figures, as can Audi, currently the only other manufacturer to use this option.
As a rule, batteries of all kinds — including the enormous ones that give today’s EVs such range — perform worse in cold weather. At the same time, temperatures above 80 °F will accelerate battery wear and limit range. In many cases, it’s not possible to avoid driving on extremely cold or hot days, but if you can keep your trips to a minimum, your battery will last longer and take you farther.
Traveling at higher speeds in an EV will deplete the battery’s charge more quickly and limit your range. Whenever possible, keep your speed below 50 mph to get the most out of each charge.
EV batteries are much larger than they were a decade ago, making them much more powerful but also forcing them to consume more energy to reach and maintain speeds. You can preserve a little bit of range by limiting heavy loads whenever possible.
Just like with ICE cars, the accessories in an EV run off the battery. The difference is that, in an EV, so does the engine. To get around this issue, get in the habit of rolling down the windows instead of running the air conditioning and limiting your use of other in-cabin accessories while driving.
Hilly or mountainous terrain is a serious challenge for EVs, which must use up more power to get you up steep inclines. There won’t always be a way around tough spots like these, but you can switch your GPS to an eco-friendly mode to find the quickest, flattest routes and save your battery.
Sudden braking and acceleration can also deplete a charge, so adjust your driving habits accordingly to get the most range.
Ultimately, a good rule of thumb is to knock about a quarter of the stated range off when you’re shopping for a new Tesla or Audi or to go for a vehicle that has been subjected to a two-cycle test for greater accuracy. And since so many journeys are much shorter than an EV’s full range — less than 5% of car journeys cover distances greater than 30 miles — it’s unlikely to be an emergency unless you’re far from the nearest charging station.
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Published October 24, 2023 2:07PM
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