I've been following a multi-month discussion over in the r/electricvehicles subreddit about EPA range. There's a growing consensus that something is very wrong with it.
Here are a couple of the articles that got some discussion in that sub:
As someone who has owned both a Tesla Model X and one of the other EVs on the list from the first article, I can also provide my own anecdata that at freeway speeds Tesla routinely underperforms their EPA range rating, and by quite a large margin. Meanwhile at freeway speeds my non-Tesla EV routinely exceeds its EPA rating.
That's not to say that Tesla hasn't done an amazing job at maximizing efficiency in their cars. They have. Just maybe not to the degree that the EPA test would suggest.
I make an app (called Nikola, not the truck company) for Tesla owners that has seen over 5 MM miles driven on it. I did some quick queries to validate actual range vs. EPA range for those curious.
My general takeaway is to see the EPA range as a useful, albeit unrealistic, indicator. Essentially nobody gets the EPA range, either because they choose not to go the speed limit, they accelerate harder than the EPA test factored in, or the vehicles drain some juice while parked.
The data: For the hundreds of Nikola trips with an average speed of 60 mph, the actual MPGe was about 102. Once you get up to a 75 MPH average trip speed, the MPGe drops to 94. And by 80 MPH the MPGe drops to 77. (avg over all Tesla types)
As a bit of "anecdata", I've driven trips where I hit my range on the nose, just to show I could, but the driving is less fun and I was going slower than traffic. I don't drive that way anymore.
What's most striking to me as someone who has heard over and over again about how air resistance is a X^2 property, is the extent to which short (and presumably slow) trips punch above their weight in terms of range consumed per mile. From what I can tell, the actual cost here is the fixed cost of booting up some systems and electronics, and the variable costs of running them over fewer miles can make the MPGe drop. Starting and continuing to run the AC adds up!
For the hundreds of Nikola trips with an average speed of 60 mph, the actual MPGe was about 102. Once you get up to an 75 MPH average trip speed, the MPGe drops to 94. And by 80 MPH the MPGe drops to 77. (avg over all Tesla types)
That makes total sense. What I think most people don’t realize is that power is force times velocity and the force you need to apply to maintain a given velocity is equal to the friction plus the drag. Unfortunately, drag increases with the square of the velocity and so when you go faster you need way more power. This translates directly into increased battery drain for an EV.
The problem may be further exacerbated by the greatly increased mass of an electric vehicle and the potential for the batteries to overheat.
Or it’s because it’s politically popular to raise speed limits since they usually raise them to the speed that is almost, but still below, the speed that everybody is already driving at currently.
Also in the US the AAA heavily invests in lobbying for higher speed limits every year. The AAA isn't quite the villains in American politics that the NRA are (ETA: or at least, have become), but they are historically close. It's easy to forget that AAA was founded to fight speed limits in the first place.
I'll admit it is something of an uncharitable view. The given reason AAA was founded was to improve the "quality" of roads in the country. One of the qualities that was seen as lacking at the time was the inability to use anything close to the top speed of cars due to road hazards and pedestrians. It's related to why AAA was the first car racing body in the country, overseeing for instance early versions of the Indianapolis 500 (though it divested racing later on).
(ETA: The search term I was forgetting was "jaywalking", because AAA was instrumental in the creation of jaywalking as a crime, related to the goals of allowing faster car travel versus speed limits. https://www.salon.com/2015/08/20/the_secret_history_of_jaywa...)
What's most striking to me as someone who has heard over and over again about how air resistance is a X^2 property, is the extent to which short (and presumably slow) trips punch above their weight in terms of range consumed per mile. From what I can tell, the actual cost here is the fixed cost of booting up some systems and electronics, and the variable costs of running them over fewer miles can make the MPGe drop. Starting and continuing to run the AC adds up!
Two factors.
First, if you go 10% faster, air resistance may be 21% higher, but you only take 10/11 for spending 10% more energy per mile. So higher speeds cost less than you'd naively think.
Second, at low speeds we start and stop a lot. Coming to a full stop requires actually putting physical brakes on and losing energy. The heavier your car, the more that this costs you. For slower traffic, if you look at distance traveled, number of full stops and energy, I bet that you can fit a linear model in 2 variables that fits the data better and gives you a sense of how much coming to a stop costs you.
Starting and stopping does cost energy, but regen is pretty efficient and the lesser wind resistance of slow speeds mostly makes up for it. No, davidwhodge is right, the problem with short trips has to do with the fixed costs of "warming up" the car. Just looking at the energy graph in the car while driving it's easy to see that it's much more efficient after the car has warmed up.
Yes, but electric motor regen usually does not work all the way down to zero mph. Usually it stops somewhere around 5-10mph, and the friction brakes take over. Slow rolling traffic that fluctuates between something like 10-30mph is very efficient, but stop and go traffic fluctuating between 0-20mph is pretty inefficient.
Air, rolling and other mechanical resistances are certainly part of the equation here, but the major driver of the decreased range at higher speeds is likely battery chemistry.
When you apply a load to a cell, the voltage sags. Heavier load, bigger sag. When a battery is operated at low voltage, it loses efficiency - the total power available decreases significantly. If you ever buy batteries for, say, building your own EV, you’ll pay a lot of attention to the C values - C1 is the capacity of the cell if it is discharged in 1 hour, C100 is the capacity at 100 hours, etc. - and there is a big difference between these values - it’s non-linear, and while the difference between C100 and C10 might be a 30% loss of available power, between C1 and C10 you’re closer to 50% - a 65% loss overall between C100 and C1.
Obviously in an EV C2-C10 are probably your most relevant numbers - but the difference in available power is significant over that range, and if you’re driving harder, putting more load on the battery, your range will be lower.
The batteries have such large capacities that the C-rates are tiny. Tesla are well beyond the point where inefficiencies in battery contribute to as little as 1% of the total range.
The kind of acceleration that would cause it to be non-trivial is not the acceleration that you would use in normal driving unless you were very reckless.
Shower thought: It would be nice if the vehicle 'docked' to the charger at home so you could power everything up and get the climate control working before you disconnected from the grid. It's not going to make a noticable difference in mileage I'm sure, but if there is a surge at power-up I'd rather take the juice from the grid.
It kinds of does that, because if you start the climate control while plugged in, it'll start drawing from the charger even if charging has already finished.
This is most often seen if you remotely turn on the climate control to warm the car up in the morning, when the car is still plugged in after overnight charging.
And with scheduled charging you don't even have to manually do this, it just does it based on your departure time. My Model 3 is always warm and toasty by 8:30 AM M-F all winter. As someone with an unheated detached garage this is very nice. At least it was before I quit driving anywhere.
Another fun fact on practical drain vs. EPA drain:
While I love sentry mode and think it's a great feature, it keeps the electronics awake. In some cases this can cause double digit per day mileage drain. Tesla has clearly been working on this though, as the numbers have improved.
> What's most striking to me as someone who has heard over and over again about how air resistance is a X^2 property, is the extent to which short (and presumably slow) trips punch above their weight in terms of range consumed per mile. From what I can tell, the actual cost here is the fixed cost of booting up some systems and electronics, and the variable costs of running them over fewer miles can make the MPGe drop. Starting and continuing to run the AC adds up!
Could this be due to the battery not being at the ideal temperature on short trips? I always noticed that the efficiency of my car is lower for the first 10 miles when commuting to and from work. Since it happens in both directions, it can't be due to terrain or road type so I was guessing battery temperature.
I think there's a good chance the energy used while parked is greater than the dashboard suggests (measuring power remaining in a lithium battery is hard!). Then when you start driving, the estimate gets more accurate, and the range disappears over the next 15 minutes or so.
This would seem totally reasonable to me. It'll take more time, but I can also dig in and see the extent of the battery heater use.
My guess is it's often cold enough for the battery to need to warm up to be efficient, but not cold enough to make it worth it to turn on the battery heater. (Your point still holds in that case)
A piece of data I happen to remember, far fewer than 10% of supercharges have the battery heater on for any period of time at all.
> The data: For the hundreds of Nikola trips with an average speed of 60 mph, the actual MPGe was about 102. Once you get up to a 75 MPH average trip speed, the MPGe drops to 94. And by 80 MPH the MPGe drops to 77. (avg over all Tesla types)
My (non-Tesla) EV only gives me trip watt-hour per mile (Wh/mi)
Using an mpge to Wh/mi converter [1], 102 mgpe = about 330 Wh/mi, 94 = 385 Wh/mi and 77 = 437 Wh/mi.
My car (Ford Focus EV) gives about 275 (conservative driving) to 350 Wh/mi. It usually gives me about 80 - 130 miles range, and the stated average is 110. I get the 80 during the colder months in a warmer clime. When I was commuting into the office (pre-COVID) I was usually doing about 70-80mph.
Alrighty here's the first graph. Note that this is average speed, so any trips with an average speed near the right by definition have some parts of the trip faster than the average, so the actual drop at 80 mph isn't quite as severe as it looks.
This is really great - thanks so much for posting! I've been hunting for a similar curve for Teslas for a while.
Can I ask:
* Which car models are included?
* You write that your methodology for this chart looks at average speed for the whole trip; if this is true, would it be feasible to apply a different methodology and divide your data up into much smaller chunks (e.g. 30 seconds) and calculate the MPGe for each chunk?
* Is there any way I could calculate a similar graph for my own car? Can I get a graph like this from your app? (I'd personally be super-interested in both being able to access my own car's curve, and also explore a 'dashboard' of the whole dataset with filters by (e.g.) model, wheel size, etc.
Cool! Can you make a graph quantifying the fixed costs of startup somehow? The startup costs do seem really high, to the point where it's pretty much impossible to hit the rated efficiency unless your trip is longer than 10-20 minutes to amortize the startup costs. I'm glad someone else has noticed this.
Looks like the purported range is analogous to stated phone or laptop battery life: ideal and unrealistic. This makes sense because the car is, in fact, run by a battery.
seems like an apt comparison. Something I forgot to mention here is that the temperature also plays a huge role. I've recently started collecting more temp data, but don't have a big enough sample size to say anything definitive beyond "driving in cold weather does reduce range". This is completely expected.
As a bit of anecdata here: Parking inside vs. outside seems to have a big affect. A slightly chilly garage vs. a cold soak outdoors understandably are quite different.
In my experience: I manage to roughly match the EPA rating on the freeway driving at 65mph (it depends on the road, on the temperature, on how much stuff/people are in the car, etc.), but it goes down quickly as you drive faster. This table illustrates it fairly well: https://teslike.com/
I can duplicate pretty much the same effect with cruise control in my gasoline powered car. If I go on a 5 hour freeway road trip with cruise at 65mph and spend 95% of my time in the right lane, there's definitely a 2-3 mpg improvement in fuel consumption, vs 75 mph. At that point it becomes a tradeoff in time vs money spent on extra fuel, and need to get somewhere in a hurry.
Over a 4.5 hour period if I can cruise at 75 mph, I will be 44.5 miles ahead of another car which departs at the same time, for the same destination, at 65 mph.
For ICE cars, it depends on what the mfg has optimized for. I had an Infinity years ago and I remember that it was optimized for 70mph precisely as per the owner's manual. Higher or lower speeds would be less efficient.
Interesting(ish) tangent - the UK fuel economy specs used to be published at a constant 56mph & 75mph. When the Mk3 Vauxhall Cavalier was launched in the late 1980s, it had great (theoretical) fuel economy, much better than its rivals, but a couple of noticeable flat spots under acceleration. Turned out Vauxhall had leaned the fuel maps at the exact engine revs that corresponded to 56mph and 75mph in top gear...
My old (14) Mustang had exactly the same thing: there was a very noticeable reduction in power at ~2000 RPMs. I always suspected that it was to improve highway fuel economy, as that's exactly where the engine was spinning at 74mph in sixth.
Presumably the Vauxhall mentioned would provide exactly the measured MPG when driven at the correct speed by any owner in the real world - hence the 'flat spot' noticed.
The defeat concept you're referring to (presumably VW's) was set to only function during a test, and not in the real world (AIUI).
VW's defeat concept was set to function only at the exact RPM's used during the test. If a real-world customer were to use those RPM's and conditions, it would activate too. In fact a CCC talk showed that 5% of regular driving activated it.
Perhaps about 5% of regular vauxhall driving was in those flat spots...
Similarly; I used to drive a "somewhat" performance enhanced Subaru Impreza WRX. One month I tried an experiment of driving as fuel conscious as I could. It improved 1 mpg over the normal 21 mpg. However in my Model S, there is a very direct and obvious correlation between efficiency and acceleration/speed.
I don't really have a problem with my effective range being less do to my driving style as long as it's predictable (and it is).
I drive an unmodified Golf GTI. Sticking to speed limits, the difference between driving aggressively in Sport mode and driving normally in normal is about 20mpg. The difference between driving normally in Normal mode and more fuel consciously is probably another 10 mpg on top of that (on a 3 hr trip, no motorway i saw roughly 8-10 mpg driving aggressively and close to 38 when driving normally. Motorway driving is a little closer, but I live in Scotland so motorway isn't usually an option)
It's one thing to have the engine+drivetrain efficiency peak at 70. But for total efficiency to be worse at 60, despite massively reduced wind resistance, is pretty suspicious.
If you really really care about miles per gallon, nearly any ICE car the most efficient way to drive is at or near idle in top gear, going about 25 mph. The difference is remarkable - a car which usually gets 50 mpg can easily get 100mpg with that approach, although obviously you can't practically drive like that on the public highway.
It's not that simple unfortunately. It's most efficient when it runs the most lean fuel mix and least engine vacuum (i.e. full throttle). That balanced with gearbox efficiency, other drive train loses, and wind resistance. As a real world example, Ford Fiesta 1.0 EcoBoost is most efficient running 28mph in 4. gear. closely followed by going 44mph in 5. gear.
But the most efficient way to drive a gas car is to speed up, then turn the engine off and coast down to a slower speed, then engine on for quickly moving up to a fast speed again.
Of course, the only way you'd want to drive like that is if you are alone in the desert and need to get to a gas station.
I noticed that my plug-in hybrid Volvo does pretty much exactly this - whenever you let go of the accelerator, not only the car goes into neutral, the petrol motor does actually switch off entirely. When you want to accelerate again the electric motor kicks in first and then the petrol motor follows, so in practice if it wasn't for the small indicator on the screen you wouldn't ever know that it's happening. Considering the size and weight of the vehicle I'm actually seeing some incredible MPG when driven carefully.
I was pretty bummed to learn that my Model 3's "real" range was about 70% of the "rated" range depending on how the car was feeling. Tesla definitely creatively interprets range calculations.
Have you reached out to Tesla service about this? The range being that far below what is advertised is not normal unless you are operating in some cold environments, you are blasting the AC, you are a maniac when accelerating, or you leave the car in sentry mode for extended periods of time. You might have a lemon.
Make sure the tires are properly inflated and the parking brake is disengaged. Also, drive smoothly (many people drive erratically going on and off the throttle, and emphatically deny it when you, as passenger, point it out).
I find that efficiency is bad on short trips, but on trips over 20 minutes long efficiency improves a lot. Not sure if the battery just needs to warm up or what. I rarely drive that long so my lifetime efficiency is 20% worse than the EPA rating.
There's also self-discharge and other consumption when not driving, which may be an even worse problem for EV efficiency. I wonder what percentage of total EV electricity consumption is wasted while the car is off.
I've had an s for 8 years (3 and 5 years in 2 cars) and driving at freeway speeds you'll use a lot more energy accellerating. On long trips I put my car on 65-75 dep on conditions and use the cruise. I get 90% of est range at least. Are you really accelerating a lot?
I can compare a leaf and a tesla, both of which I have had direct experience with.
The leaf did lots better around town, but it was a relatively small and light car. The battery was charged significantly higher and drained significantly lower than tesla batteries. There was degradation. At highway speeds it was significantly less efficient and range anxiety became a real problem. On trips usable range was much less than the specs because: you couldn't drain it all the way because logistics was a real problem. You also couldn't charge it all the way because a "fast" charger would take as much time to charge to 80% as from 80%-100%. Range was an issue and being an engineer or mathematician helped. Around town 3.5-4.5 miles/kwh was common, on the freeway you would hit 2 at 70mph.
The tesla actually had freeway speeds. Where a leaf would have you in the right hand lane trying to go as slow as possible, the tesla would have you looking out for speed traps. The battery was huge. You could plan your trips with the help of the nav computer and your battery would generally stay in 20-80% range. On long trips it was better to stay 10-60% because the battery would charge faster before it started tapering off. By tapering off, I mean 2-3x the max the leaf would charge on a good day. I will say that tesla battery size makes it possible to care for the battery. It would be uncommon (and sort of bad maintenance) to charge to 90% let alone 100%. Same for below 20%. Telsa shuts off some automatic climate features below 20%
Oh, and tesla drivers are a diverse group. Just talking to them, some will average close to 200 wh/mi, while others will be above 400wh/mi. climate and foot weight make a difference. Besides behavior, there are also several tesla settings that will increase your range. Range mode, different driving settings [chill | standard | sport | ludicrous | ludicrous+ ] depending on the vehicle.
Oh yeah, The leaf was scarey on the freeway. It would burn so much battery and was pretty loud. I try to keep it below 60MPH in which things get uncomfortable. In the city it was very compliant and very efficient. I could go through two weeks without charging my now half degraded battery.
In the Tesla it loves going to about 70mph. After that you start getting wind noise.
Two very different animals. But both great cars. Never going back to ICE.
I've never ridden in a Leaf or other compact electric but is it really worse than the 2002 Tauruses and 1999 Grand Caravans (or 2019 Mitsubishi Mirage for that matter) that people seem to have no problem keeping up with traffic in?
I can see it being worse than whatever people who are buying leafs are trading in but I can't see it being that bad overall.
The issue is not you can't keep up with traffic, it's if you do keep up with traffic, you use your stored energy very fast.
I was commuting with a plug in hybrid and it was very similar. If traffic was bad, I could make it nearly home on nearly all electric, but if traffic was light, the battery would be drained even if it was running in normal hybrid mode. Not a problem for me, the gas engine works fine, but it would be an issue for a leaf.
My understanding is that the Taycan was seriously screwed by having its track modes, which are genuinely very inefficient, blended equally in to the test.
It's a bit of a shame to see so many Tesla fans point to its supposed inefficiency based on the EPA range. It feels like the tables have turned 180 since the Top Gear scripted test days; it was shitty when Tesla was attacked with FUD back then and it's shitty when the Taycan is today.
Unfortunately I'm struggling to find a source, so take it with a grain of salt. My memory is that the highway speed test for one of the modes had it running in first gear (of two).
But regardless of the reason, its EPA range proportional to WLTP and real world driving is very low compared to other EVs. It doesn't point to poor efficiency, just a corner case of EPA testing.
While extrapolated from 100 miles, this Car and Driver test [1] puts a 6% gap between the 2020 Model S and Taycan, compared to a 70% difference in EPA range. Extrapolation sucks as a method, but there's no way it would mask a true 70% range difference - the Porsche would be close to empty at the end of the test.
Considering the Tesla costs just over half as much, it's still a home run for Tesla. They're the ones to beat and by all accounts are likely to stay that way.
It makes sense to me, as otherwise a manufacturer could supply the car with a 50mph speed limiter (which users would instantly disable) to boost their EPA-measured range.
My memory (and I don't have a citation for this) is that if the manufacturer gives you multiple range modes (like Eco and Sport) EPA tests in both, then averages them together somehow.
Why does actual EPA range numbers matter, when we all know they aren't perfectly accurate? They aren't accurate for ICE cars either.
The point is Tesla has increased their range yet again. There is no disputing this fact. If people were buying Teslas before, they're getting even more value out of it now.
It seems most people here find this EPA discrepancy a great justification for criticising Tesla, but I highly doubt anyone owns a Tesla who is doing the criticising.
Most Tesla owners were happy to buy the Model S at 265 EPA range. Now its 400, almost 50% more. Who cares if that actually means 300 miles? That 300 miles is still awesome, and if its good enough to buy a Tesla, buy one. If not, don't.
For me, the EPA range numbers are important because I'm in the market to buy a new car later this year and I'd like a fair gauge to compare vehicles on expected milage (part of the reason is wife has mileage anxiety, which I believe a lot of non-EV people have as well).
Looking at the first article the lead commenter posted that compared "real-world" to EPA ranges, Tesla misses the EPA range by an average of 22%. Other vehicles that miss the EPA range average 4.5% off.
Of course the EPA range is as much an estimate as the testing is and conditions change between testing and real world scenarios, but what's so different with the Tesla vehicles during EPA testing compared to real-world testing to cause such a large drop-off compared to other vehicles.
We can rightly question the EPA testing methodology in the first place meaning, what are they running (or not running) that regular people would. For example, does EPA not run the A/C during the test? I'm not accusing the Tesla A/C from excessive battery draw, as it's just an example.
Yes, having a larger battery is welcome, so with an EPA range of 400 miles, then we can real-world expect 320 miles.
*Quick addendum: I'm not a big fan of these types of articles and can more then accept that the testing the article performed was "flawed" as well. But we do need better, consistent range tests.
Because ideally consumers should be allowed to make informed decisions, which is not possible if one party - willingly or not - misrepresents the numbers.
Tesla should be criticized for every number they inflate. Every time they pull some marketing crap, they should be called out on it.
If it's such a benefit as you write, why do they feel the need inflate the numbers?
What happened to honesty among engineers? Understated performance, instead of throwing around huge numbers that are technically possible but are nothing short of misleading for the consumers? I suppose it clearly works for Tesla, but my support goes to the company who claims a conservative number that I'm actually likely to exceed in reality.
Is there evidence that they are misleading or cheating? The EPA numbers (I assume) are arrived at with the same methodology for all cars. It's indepedent right? (I have no idea).
So how is Tesla at fault here, if their cars do well. Btw, you can get the EPA range if you drive around 55-60mph... So it is misleading?
It is not independent. The EPA defines the test methodology and the manufacture conducts the test themselves. There are some loopholes that manufactures can leverage to improve their score, like offering a model without A/C, tiny tires, or tall gearrs; having a "eco" mode; or having a shift light on the dashboard.
The EPA test methodology is actually pretty sound. It includes things like multiple wide-open throttle accelerations to highways speeds. The problems appear to be lack of independent testing and the existence of loopholes mentioned above. Companies like Honda seem to always beat EPA #s and Ford always seems to fall very short of the numbers.
All those things you list as 'loopholes' aren't something Tesla is doing here, besides maybe the smaller tires (which really, aren't undersized, they're just the smallest ones they offer happen to get best range).
I'm not sure what you'd expect, given that every single defined test can be gamed. 'Real world' is different for everyone. And if you drive 80mph, every single car ever will underperform compared to the stated EPA range/mpg.
There's always a lot of folks claiming to get equal to or better than the rated range on the highway, but I will add my anecdata in for however much it's worth. I have a Model 3 Performance and it does not get anywhere near rated range, regardless of weather. I more realistically get 200 miles of range, not 300.
I find in my model 3 that unless I put it on cruise control I can never get close to the rating. Cruise control gets almost right on the money and cuts down the urge pass people for fun.
Around town, for sure, but on a road trip with the fam I just set turn on autopilot at 70 and leave it. My wife & kids are not nearly as appreciative of the performance as I am :).
But, even at mild temperatures cruising at steady speed on mostly level terrain, I generally see 325 Wh/mi. If I cruise at 75, it's 350 Wh/mi. The rated range can only be achieved by hitting about 250 Wh/mi.
Assuming you have the 20 inch performance wheels (and the Pilot 4S summer tires that come with them), those could be the difference between you getting 325Wh/mi and something more in line with 250-275 at 70mph.
Here's a chart with speed/efficiency measurements for most Tesla model/wheel configurations:
That is entirely possible. When I drive out of my driveway and down the road, it sounds like the tires are ripping the asphalt off the road and flinging at the underside of the car. Sticky things.
In the winter I run snow tires, but then there's the low temperature and corresponding use of the climate control that destroys range. And in the summer I've got the performance wheels and tires installed. So I'll never see optimal range. But Tesla probably shouldn't be quoting 300+ miles of range for the Performance model, either.
Given the climate where I live is pretty mild, and snow is relatively rare and short-lived, I've given some consideration to ditching the performance tires and snow tires both and replacing with 19 inch Conti DWS to run year-round. If I got away with that on my Camaro, it would probably work on my AWD Tesla, LOL.
Late response but, to Tesla's (slight) credit, they now advertise the performance (with 20" wheels) at 299 miles, and that's in comparison to the 2020 improvements that bumped the advertised range for LR AWD to 322 miles (from 310), so at least now expectations should be a bit more clear for new buyers.
Yeah, I'd imagine running all seasons on 19s or 18s ought to be fine, especially with the killer traction control... This would be my plan in the event I were getting a P3D (trying to hold out for Cybertruck...)
P.s., the way you describe the summer tires ripping up the pavement gave me a chuckle - I'll have to remember that next time I'm talking to someone about the difference with the summer tires!
Sounds like they have the mix of estimated speeds wrong. EVs perform significantly better at low speeds, because there’s no extra efficiency in the EV power train at higher RPMs, and air resistance scales in a nonlinear fashion.
The trouble is you just can't trust anecdotes when it comes to driving at "freeway speeds". I had the displeasure of taking part in a two hour commute every day for a few months and the difference a few mph to your average speed makes is huge. If I travelled at 72mph average (above the national speed limit, which is the speed most seem to drive) I needed 2.5 tanks of fuel per week, but if I travelled at 68mph and made an effort to use high gears, low acceleration, engine braking over friction braking etc. I would need only two tanks.
To add to this, it's especially difficult to exercise the restraint necessary to drive economically in a fun and/or comfortable car. Before I got a comfortable car I didn't understand why BMW/Mercedes/Audi drivers drive so fast. Now I do. It doesn't really feel like you're moving very fast in those cars.
Teslas are designed to perform better (and EPA is designed to evaluate) NOT on freeways (ie, where most people drive)(mainly due to very good regenerative braking).
All cars perform better (in terms of kWh through the driveshaft per km) at lower speed, since air resistance rises quickly with speed. Tesla can't do anything to change this, although they do try to mitigate it with good aero.
Electric cars can regen brake and so recover some energy in stop/go traffic, but they're still more efficient at constant low speed than stop/go at low speed.
ICE vehicles only get better economy on the highway because they have no regen braking and their engines are more fuel efficient at highway speeds.
This is not complete true. Most combustion cars perform best around 90km/h. Below that speed air resistance is not much of an issue but gears help a lot getting the best performance out of the engine.
Yeah, that's what I meant by "their engines are more fuel efficient at highway speeds" - fuel burn is minimized under highway conditions (90km/h as you say sounds about right) since air resistance isn't crazy yet but you're in top gear and so getting the maximum distance per engine swept volume.
90 km/h or 56 mph was the speed that ICE car fuel efficiency was measured at during the 1970's onwards until recent times. If you read a car review then the mpg figure would be for 56 mph in the UK.
For this reason the target speed for efficiency had to be 56 mph. For that would be important for comparisons. Fleet buyers were important in those days so a 'rep-mobile' able to sip the fuel as it went about crossing the country at sensible A road and motorway speeds was what was wanted. If a manufacturer wanted to sell into this market then the 56 mpg figure had to be available.
I am not sure fuel efficiency was discussed in quite the same way in the U.S. market during these times and there weren't the same tax incentives to get companies buying 'rep-mobiles' so the auto-sector could be stimulated.
Europe wasn't the EU in those days with each major country having different tax regimes for cars.
My 3 can exceed its rating very easily under the correct conditions. No elevation changes, about 80 degrees out, and cruise control at a steady 60. But any variance from that and it is definitely different. I have a lot of elevation change on my daily commute, and going up those hills fast does the range no favors. But on average I am pretty darn close to the rated distance. Temperature is a huge factor, if its below 45 efficiency is like 70%. If its over 90 efficiency is under 90%. Doing 80 MPH, also pretty bad for the rating. So now do 80 MPH in 95 degree weather and you are talking maybe 80% efficiency. I feel the rating on the 3 has been spot on for me, understanding the large number of variables that go into actual real world use.
EPA range is city+highway combined, which isn't really what any most car buyers care about. Range during city driving is irrelevant beyond a point; you're never going to go more than 100 miles per charge. Then the highway test is easy; it never breaks 60 MPH and averages 48 MPH. What most people probably care about is how far you can go between charges when road-tripping, which is really a much more complicated formula involving how quickly you can charge, what the real speed limit is on your local highways, how many high speed chargers are available, etc.
48mph was easily doable during moderate traffic on my commutes back home. Some days I'd be lucky to get that.
So it's a bit more honest in that regard... Those days where I got to go 80mph the entire freeway segment and get home really quickly my mpge suffered a lot.
It’s not just about speed, although speed has a lot to do with it (with efficiency dropping with the square of the increase).
It depends also on how much you use the available acceleration features.
As you will know there is quite a range of acceleration available, from barely pushing the pedal and matching normal cars, to putting the pedal about 1/4 of the way down and smoking even most fast cars, to putting the pedal down more than halfway and having a beast in your hands.
I’m sure the EPA is pretty conservative and this is where the literal meaning of ymmv comes into play.
There are some reviews of the Porsche Taycan where the car lost most of its range very quickly when the driver was accelerating quickly.
The Tesla Model S is one of the fastest-accelerating cars available at any price. If you drive it like a normal person and obey the speed limit (approximately), you will get close to the EPA rating depending on weather etc. If you actually use all the power it has (and you manage not to get pulled over), you will have lower range and you'll need to buy new tires every 6 months.
Yes, this is why they have these tests attempt to do this in an apples to apples fashion, and the most scientific of these tests seem to show Tesla overestimates their EV range the most of any automaker.
"Manufacturers test their own vehicles—usually pre-production prototypes—and report the results to EPA. EPA reviews the results and confirms about 15%–20% of them through their own tests at the National Vehicles and Fuel Emissions Laboratory.[6]"
Actually in the recent Model S test prior to this one, Tesla discovered through examination of the data logs of the car that the EPA had carelessly left the key in the car all night while it was parked during testing that spanned multiple days, leading to an artificially low number as the car was unable to sleep at the level it normally should be able to when parked.
This whole episode happened because the EPA was doing the testing… I don't know where that leaves your anecdote. It's just false, I think. I love Wikipedia and even have a monthly donation to them, but your link is not reflecting what happened with Tesla here.
OK, fair point. Allow me to quote from the EPA directly. [1]
"Manufacturers test their own vehicles—usually pre-production prototypes—and report the results to EPA. EPA reviews the results and confirms about 15%–20% of them through their own tests at the National Vehicles and Fuel Emissions Laboratory."
And I'm not sure how an indication that a Tesla has been tested (and retested) invalidates a claim that 15-20% of all cars are tested. There have been dozens of Tesla models over the years, one would expect at least a handful to have been verified.
Which by the way would have totally sufficed to invalidate the original argument; the ranges are largely self reported, but they do get checked. The process ensures that the ratings broadly reflect EPA's testing methodology, otherwise you'd see the cars that do get tested having abnormally low range at best, and fines and other action taken by the agency at worst.
A Wikipedia link might be a crappy form of "proof", but as near as I can tell the parent post just made up how he or she thought the process worked. If someone says Caesar lived in the 9th century, a link to the relevant page actually is a valid response. If that person comes back with some source material that says otherwise, then you'll need to try harder.
Depends on the model. For Model 3, they generally sandbag (underestimate). For some versions of Model S, they have inflated in the past. For this version, I don't think we outside of Tesla know yet. They have plausible reasons to go either way. YMMV.
Maybe offtopic but I think a huge issue could be if gas cars are tested with ethanol free gasoline whereas in real life you’re mostly buying 10% ethanol.
My Tesla Model 3 SR+ tends to exceed the EPA rating on most trips, but the Model S loaners I've had have been quite a bit more thirsty and varied greatly, although I couldn't help but play with all the extra power they have. Still blows the pants off anything else as far as efficiency.
> I can also provide my own anecdata that at freeway speeds Tesla routinely underperforms their EPA range rating, and by quite a large margin. Meanwhile at freeway speeds my non-Tesla EV routinely exceeds its EPA rating.
But EPA rating is a mix, not a freeway rating. Though fueleconomy.gov has specific numbers for freeway speeds as well.
My venerable 2017 S90D is listed with 294 miles range, that's 473 Km, or 19.8 KWh/100Km. My last trips to Italy used pretty much exactly 20KWh/100Km (2500-3000 Km each time, more than 90% highway at 120-150Km/h [sorry Italy]). In the city I'm usually below that on average.
Look at these articles. They've collected data for real-world range vs speed in various models, and how fast supercharging works in various situations.
Tesla Model 3 Performance vs RWD consumption - Real Driving Data from 233 Cars
There's plenty of data and test results out there. But range is very subjective. It varies hugely depending on driving style, speed, road surface, traffic, weather, temperature, tires, vehicles configuration/settings, etc.
Apart from going through r/teslamotors or Tesla Motors Club forums (plenty of personal reports on those), here is an aggregation of efficiencies for most Tesla model/wheel configurations at various speeds:
Given that Tesla track everything on every car - where they go, how they drive, when and how much they charge - they ought to have accurate data themselves apart from EPA ratings.
Could customers demand their own data from Tesla? Europeans, under the GDPR, for example? If enough people did, and released it, that ought to be accurate.
Don’t single Tesla out on this. No car manages to get its official mpg/EPA rating in real-world driving conditions. Some get closer than others and some manufacturers (eg Fiat) designed their motors in a way that maximises their performance on standardised tests. The gap between how ‘hard’ the car has to work to achieve the real world driving conditions vs test conditions plays a big part in the differential. Smaller motors with forced inductions are the worst offenders. Larger motors are more honest citizens.
>Don’t single Tesla out on this. No car manages to get its official mpg/EPA rating in real-world driving conditions.
It totally depends on the vehicle. I maintain a fleet of ~10 vehicles and keep records of fuel economy (because it tells me when calipers stick before the drivers do). The vehicles get ridden decently hard and pretty much all the highway miles are in the left lane at whatever speed that may be. A 2/3 majority pretty much always exceed their EPA rating by 2-4mpg. The rest are right on the rating. None of them spend much time in the gridlock that tends to characterize upscale inner suburbs during daylight hours nor do they cruise empty rural highways.
The difference between your non tesla-ev and other's tesla evs may be nothing more than driving habits, including how you drive, road and weather conditions, etc.
Even with 100% efficiency of the powertrain you'll end up with less charge than you started with. Yes, with 100% you get the energy used to overcome gravity back, but you still have frictional (tyres have friction!) and aerodynamic (we have an atmosphere!) losses that need to be accounted for both uphill and downhill.
But yes, powertrain loses exacerbate the power consumption.
The question is whether flat or hill makes a difference. Surely friction and aerodynamic would be the same?
Also: friction of tyres don't make you consume energy, it's what makes the car move actually (with no tire friction you won't move at all).
The friction that makes you consume energy is within the wheels, gears, etc that are supposed to slide, also the deformation of tires makes you consume energy (which is why consumption is higher with under-inflated tires).
There's wasteful forms of friction at the road:tire interface when steering, look up slip angles. And there's always wasteful friction at the road:tire interface due to factors like toe and camber, even when going straight. The tire's not a perfect cylinder in isolation rolling perfectly straight down a perfectly flat surface, automobiles are not single-track vehicles.
Since we're already in pedantic land, tires aren't spinning in a vacuum, there's friction between the spinning tires and the air around them.
Disagree strongly. Hills most definitely impact mpg/mpge. If you're going near speed limit (due to flow of traffic) then your regen isn't going to recapture as much as if you let it coast.
I wouldn't be surprised by a ~10% loss in range, which could be enough to make the EPA numbers look bogus to some drivers.
Presumably there's also a subjective element, like if the driver tends to tailgate and brake late, which isn't exactly uncommon. You're not recovering any energy put into heating the brake rotors.
There are also plenty of locales where you're repeatedly braking heavily for hairpin turns like winding roads on the side of a mountain. Teslas aren't exactly light vehicles...
Here are a couple of the articles that got some discussion in that sub:
https://insideevs.com/news/407807/eletric-car-real-world-ran...
https://www.caranddriver.com/reviews/a30874032/porsche-tayca...
As someone who has owned both a Tesla Model X and one of the other EVs on the list from the first article, I can also provide my own anecdata that at freeway speeds Tesla routinely underperforms their EPA range rating, and by quite a large margin. Meanwhile at freeway speeds my non-Tesla EV routinely exceeds its EPA rating.
That's not to say that Tesla hasn't done an amazing job at maximizing efficiency in their cars. They have. Just maybe not to the degree that the EPA test would suggest.