Tesla vastly overstates its vehicles’ range, report states

A new report out today details that Tesla, the world’s leading electric vehicle maker, is gaming the EPA system to vastly overstate its vehicles’ range and also diverting claims from drivers who are seeing as little as half the range…

The Reuters investigation uncovers a lot of details on the inflated numbers that EV experts have known about for years, charitably calling Tesla’s range estimates “optimistic.”

Tesla years ago began exaggerating its vehicles’ potential driving distance – by rigging their range-estimating software. The company decided about a decade ago, for marketing purposes, to write algorithms for its range meter that would show drivers “rosy” projections for the distance it could travel on a full battery, according to a person familiar with an early design of the software for its in-dash readouts. Then, when the battery fell below 50% of its maximum charge, the algorithm would show drivers more realistic projections for their remaining driving range, this person said. To prevent drivers from getting stranded as their predicted range started declining more quickly, Teslas were designed with a “safety buffer,” allowing about 15 miles (24 km) of additional range even after the dash readout showed an empty battery, the source said.

The inflation, as is often the case of controversial actions at Tesla, emanated from the top, according to Reuters.

The directive to present the optimistic range estimates came from Tesla Chief Executive Elon Musk, this person said.

“Elon wanted to show good range numbers when fully charged,” the person said, adding: “When you buy a car off the lot seeing 350-mile, 400-mile range, it makes you feel good.”

The inflation of numbers vs. reality is pretty easy for most people to spot. Tesla was fined $2.2 million by the Korea Fair Trade Commission (KFTC) for falsely overstating its range earlier this year.

Recurrent, which we’ve detailed previously for winter range, has today put out numbers directly from vehicles on the range of Tesla vehicles vs. real range. And it isn’t even close.

Note: Recurrent is a past sponsor of Electrek’s podcast

Even in summer, the 2021 Tesla Model Y, which advertises 326 miles of range, barely hit 250 miles and averaged closer to 200 miles. Meanwhile in winter, even with its octovavle heat pump, owners were seeing ranges that vary from 124-235 miles.

The range of an electric car is never constant. Each of the thousands of owners currently connected to Recurrent knows that there is a range estimate from the EPA, a range estimate displayed on the vehicle dashboard, and an actual range. These three ranges rarely overlap, and only get more complicated as the battery ages. 

Recurrent tested other automakers’ in-dash range meters –  including the Ford Mustang Mach-E, the Chevrolet Bolt and the Hyundai Kona – and found them to be more accurate. The Kona’s range meter generally underestimated the distance the car could travel, the tests showed. Recurrent conducted the study with the help of a National Science Foundation grant.

Reuters

The important thing to consider with Recurrent numbers is that Tesla owners aren’t necessarily trying to get good range. They are often driving Teslas fast and often without preheating them. Range only really matters for most people on long trips. Recurrent is taking in data at all times, not just trips.

An SAE (Society of Automotive Engineers, also an Electrek Podcast sponsor) rep told Reuters that three Tesla models posted the worst performance of all automakers in range vs. EPA estimates, falling short of their advertised ranges by an average of 26%.

The EV pioneer pushes the limits of government testing regulations that govern the claims automakers put on window stickers, the three automotive experts told Reuters.

Jonathan Elfalan, a vehicle testing director of Edmunds, said, “[Tesla has] gotten really good at exploiting the rule book and maximizing certain points to work in their favor involving EPA tests.”

How does Tesla get its inflated numbers by the EPA? According to the report, Tesla feeds its own numbers to the EPA.

EV makers have a choice in how to calculate a model’s range. They can use a standard EPA formula that converts fuel-economy results from city and highway driving tests to calculate a total range figure. Or automakers can conduct additional tests to come up with their own range estimate. The only reason to conduct more tests is to generate a more favorable estimate, said Pannone, a retired auto-industry veteran.

Tesla conducts additional range tests on all of its models. By contrast, many other automakers, including Ford, Mercedes and Porsche, continue to rely on the EPA’s formula to calculate potential range, according to agency data for 2023 models. That generally produces more conservative estimates, Pannone said.

But according to the report, the EPA goes over the numbers and only drops Tesla’s estimates slightly.

EPA data obtained by Reuters through the Freedom of Information Act showed that the audits resulted in Tesla being required to lower all the cars’ estimated ranges by an average of 3%. The projected range for one vehicle, the 2021 Model Y Long Range AWD (all-wheel drive), dropped by 5.15%. The EPA said all the changes to Tesla’s range estimates were made before the company used the figures on window stickers.

The EPA’s numbers still vary greatly from other independent testing sources. Not by 3% but by 30%.

Interestingly, recently Tesla has been guiding its EPA numbers lower, saying that all models of its Model 3 LR were seeing 310 mile range.

For more info on the EPA testing process, see the EPA’s spec page

Range Testing for Electric Vehicles

An all-electric vehicle (EV) produces no smog-forming or greenhouse gas emissions from its tailpipe. For EVs, vehicle testing provides important label information, such as fuel economy and range.

For EV range testing:

1. A vehicle with a fully charged battery is driven continuously over the EPA city cycle until the battery is depleted and the vehicle can drive no further. The distance driven is recorded. This is repeated, again starting with a full charge, over the EPA highway cycle, again recording the distance driven when the battery is depleted. This “single cycle” test consists of multiple repeat drives of the city or highway cycle.
2. Automakers also have the option of doing a multi-cycle test, which consists of four city cycles, two highway cycles, and two constant speed cycles.*
3. All testing is done in a laboratory on a dynamometer.
4. The city and highway driving ranges determined from this testing are adjusted to account for real-world factors that are not represented on the laboratory test procedures. These factors include such things the impact of air conditioning, of cold temperatures, and of high speed and aggressive driving behavior. Although the regulations allow some optional approaches, the most common approach is to use a factor of 0.7 to adjust all the test parameters, including range. For example:
   • An EV achieves 200 miles on the highway laboratory test. Real-world highway driving range → 200 x 0.7 = 140 miles to account for aggressive driving and HVAC use.
5. The adjusted city and highway range values are weighted together by 55% and 45%, respectively, to determine the combined city and highway driving range that appears on the EPA fuel economy label. For example:
   • Assume an adjusted city range of 168 miles and an adjusted highway range of 140 (from example above). The official combined range value → (0.55 x 168) + (0.45 x 140) = 155 miles (values are rounded to the nearest whole number).

Specific details on testing can be found in EPA regulations at 40 CFR 600.116-12 – Special procedures related to electric vehicles and hybrid electric vehicles. For more information on the other acceptable (“optional”) approaches, visit 40 CFR 600.210-12 Calculation of fuel economy and CO2 emission values for labeling.

Diversions?

Reuters also goes into what it calls a diversion team at Tesla call centers that cancel service appointments from people who think that there is something wrong with their cars because they don’t hit the range estimates.

That’s hardly controversial since the Tesla service centers aren’t going to be able to help customers beyond letting them know how to “hypermile” and start their journeys with warm batteries, and, of course, drive slowly. This however is…concerning:

If the remote diagnostics found anything else wrong with the vehicle that was not related to driving range, advisors were instructed not to tell the customer, one of the sources said. Managers told them to close the cases.

Electrek’s Take:

As an owner of every Tesla (except Roadster), I can say firsthand, unequivocally, that Tesla’s range estimates are becoming a joke (at least in my family). And it is easy to prove. Simply jump into a new Tesla with 350 miles of range. Map to a place 300 miles away and Tesla will tell you that you need to make a stop at one of Tesla’s many excellent Supercharger stations to get there. Also you can check the energy app after routing a trip and it will give you real-world range that is often around 70% of Tesla’s official EPA range estimates. This app is actually pretty impressive as it uses temperature, road incline, decline and other pieces of info to give real range.

Compare my Rivian R1S or my Chevy Bolt with much more conservative estimates. My wife and I were recently astounded to see our Rivian range estimates go up (!!) as we were driving to Vermont from New York last week and we ended our 180-mile trip with 160 miles of range. That was almost enough to make the return trip. Our similar EPA range “326 mile” Tesla Model Y, the same one from the graphic above, usually ends that same trip in the summer with about 30-50 miles of range. If we are taking bikes, we need to make a Supercharger stop. It isn’t even close. My previous Teslas, with the exception of the Model 3, were much worse.

Similarly, the Chevy Bolt will consistently underestimate the range it offers, often allowing me to drive more than the 259 miles of EPA range it has in summer. It over-adjusts lower in winter telling me I have around 50% of the rated range when in reality I can go 70-80%.

Tesla needs to come up with real-world estimates, or better yet, the EPA, which should be regulating better, needs to test these vehicles against each others directly instead of relying on the automakers’ data.

Until then, EV owners should rely on third-party tests like those from Recurrent. Or get into the Tesla you are about to buy and map to a place 300 miles away and see if that Tesla can get you there without a charging stop.

Update: For science, I tried to map to State College PA, 261 miles from my home on a 74 degree day. My 326 mile Model Y can’t make it with a 88% charge. It isn’t even close. Anything over 215 miles requires a stop. Sure, I can charge to 100% but that will only buy me up to about 240 miles.

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