In a recent review, a Tesla did a slightly better job than most of the cars tested, as far as portion of stated range achieved.
Most people speed on the freeway. Extra speed reduces range significantly.
The linked figure[0] and associated paper report that efficiency peaks for EVs at around 20mph and then the cost per mile increases roughly linearly, by about 25 watt-hours when the speed increases by 10mph.
Please excuse the archaic units.
[0] https://www.researchgate.net/figure/ehicle-energy-economy-at...
And it is true of petrol cars as well. In my old clunker going from 110 km/h to 120km/h is a 9% speed increase but nets about 15% extra fuel consumption.
I just finished a long drive for summer vacation. Driving through Denmark (completely flat) at 130 km/h would absolutely wipe the battery, would be surprised if I managed even 350 km on a full charge. Driving over the mountains in Norway however, from 0m elevation to over 1000m and down again, at slower mountain roads (max 80 km/h), yielded almost 500 km on single charge.
I did not expect flat+high speed vs hill-climbing+low speed would be that dramatically different.
I have a 2022 Nissan Leaf with 220 miles EPA range. I've found that this number is reasonably close to correct if one is driving under 60mph on country roads under moderate climate conditions. We live in Ohio and so I have actually done long drives like that to go to remote places to go camping. (There are, surprisingly, both L2 and fast chargers around in rural Ohio but you definitely need an app and need to check ahead of time.)
Speed matters because air resistance increases exponentially with speed, not linearly. Driving 60+, lots of stop and go, or using HVAC a lot will bring it down the range to as low as 180, but that seems like the worst range I've seen. That was driving ~75mph with HVAC on.
No, drag is somewhere between linear and quadratic as a function of speed, not exponential. (Although it gets weird around the speed of doing.)
Heuristically, if you’re pushing through a cloud of particles, the number of particles you hit per unit time is linear with speed, and the impulse per particle is also linear with speed (because it’s the difference between your velocity and the particle’s initial velocity, times the particle’s mass, times a constant that’s around two for an elastic collision).
The set-up is so dangerous but so tempting.
The routefinder 'learns' from your previous driving habits. Driving style easily has a 50% impact on range between "drives 50 mph slipstreaming behind a truck" and "drives 90 mph and brakes aggressively at every corner".
Regen breaking increases range over no regen braking, but braking aggressively will always be worse than not braking aggressively.
Most EVs (including Tesla) do have regenerative braking, so some of your energy is converted back into electricity when you brake, but nowhere close to all of it, so people who have a smoother, less aggressive profile will get more range.
Also if you brake really aggressively, you're dissipating more energy than can be successfully harvested and the rest is converted to heat, losing the energy you paid for and also increasing maintenance costs.
The meter is presenting you the regeneration “rate” but what you’re thinking of is the regen rate integrated over time, I.e the amount of charge recovered during the process of stopping, which the meter is not showing you.
(Also, Tesla cars do have blended braking between region & friction...)
Also, its still better to arrange to not need to brake at all, than to regen, since regen is not 100% efficient.
All these comments about ICE vehicles being the same ignore that when ICE vehicles have estimates to empty, they take basic steps to try to get the estimate correct.
Tesla should probably not allow you to show the battery as range as it will always be inaccurate and people will complain. But if they only show percentages, people complain as well.
I guess I'm flabbergasted by this, as that's not how my Chevy Volt (and I presume many other BEVs) work. The range value ('guessimeter' people call it) on my Volt takes something like a rolling average of your last few drives and that's what it shows you. So if it's winter, it shows you less range because your last few drives had less efficiency. It's not always accurate (if there's, say, major temp fluctuations), but it's way more useful than what you're describing.
To me, what you're describing is border line dishonest marketing, and technically unnecessary.
What I'd like to see is two numbers: estimated range as I've described, and beside it a kWh # (which I can guesstimate from the battery % gauge visual, but not precise).
I leave the dashboard meter set to percent because the “miles” option is just the dumb EPA rated range mapped to percent anyway.
The real way to predict range in a Tesla is to use the nav system which takes many factors into account and has been very accurate in my experience.
But could also reflect that this is a California company where they don't really have weather.
Many here complain about how inaccurate Tesla's range calcs are driving to Tahoe. It's not the state, it's the amoral response to incentives.
“Accurate range” is difficult. It could be accurate based on recent driving, but that number could be very inaccurate if there is a change in weather or you are taking a different kind of drive than your last one.
We are HN tech crowd here so its all fun & games hobbyist stuff.
But normies do not want to get into these types of inane subtleties.
Arguably the front & center, always-there range display should be the most accurate, not the least accurate.
The car doesn’t know where you are going, whether it is city or highway driving, whether or not there is an elevation change, unless you tell it by navigating somewhere.
It could take a guess, but that guess still has plenty of chances to be wrong if your next X miles of driving is not going to be similar to your previous X miles of driving.
There's plenty of smarter things it can do by default other than "its hard, meh".
They are gonna figure out how to do coast to coast self driving this year but can't project a reasonable battery range estimate given temperature/driver history/weather? Do they need more GPUs?
If you mostly drive around town, that estimate will be way off when you get on a highway to go to Grandma’s house.
There’s probably a better way to do it, but Tesla seems to be optimizing for avoiding the “why does the website say 300mi but my car shows 200mi fully charged” support question, in exchange for a different set of support questions.
I think ideally the car would give a best guess estimate, along with a clear breakdown of why this is more or less than the rated range. I just don’t think that’s clearly the “most accurate” option. Most accurate requires knowing where you are going.
It feels like one of those Muskisms where one bending of the truth requires more and more stuff down the line.
If they weren't over optimizing for the EPA test to give almost unachievable range, then they wouldn't need to have the car range meter lie as well. But if you fib once, you need to keep fibbing and keep the fib straight.
It can also vary dramatically based on how you drive, and in fact, if you do have a destination, it will give hints if relevant (e.g. "keep speed below 70 mph to reach destination").
You can switch the EPA-rated miles for a battery percentage indicator by just tapping it in the UI.
There's A LOT of smarter things the car can do than use its factory set 0.250 kWh/mi consumption to spit out the range on dashboard.
Erring on the side of caution would also always be better, whereas it is erring on the side of showing the absolute best state that I as an individual never experienced in 4 years of ownership.
The best state would be over 600 miles [1].
It's erring on the side of consistency, as it's also representing the battery's state of charge. It would only serve to confuse users to try and guess whether the current trip is a highway or city drive, will end in the next minute or two hours from now, which way the wind will be blowing and whether or not you're driving uphill, etc. It'd just be a useless guess, instead of an at least consistent one.
If you tell it where you're going, it already gives you a great estimate, as it doe stake into account all of those factors.
[1] https://www.theverge.com/2018/5/29/17405906/tesla-model-3-hy...
But all the "just use nav estimate" arguments miss that some people drive more than one place?
If I am driving out an hour to do some shopping, visit my parents, and then drive back.. it may be a total of 90mi but the first leg is 30mi. Do I need to pre-enter my round trip as multiple waypoints to get an accurate view of whether I will make it home or not?
Seems silly.
Just guesstimate a more accurate dashboard view range like you do in other place sin the UI.
The other places in the UI are either based on either the destination you've entered or the last 5, 15, or X miles driven. They only make sense in that context: Just using one of those numbers on the dashboard would be misleading and inconsistent.
Guessing based on the Wh/m of your last ten drives might be a closer estimate, but would be wrong if your next drive isn't like your last ten. It might even be more accurate when guessing your last nine drives, so then you learn to trust it, but those were city miles, and for the next drive, it's highway miles. And now the estimate is way off.
It's just meaningless. We'd quickly learn that the number given is a bad estimate that can't be trusted and needs to be adjusted based on the way you'll actually be driving and other real world conditions... and that's where we already are. The only difference is that currently it's at least consistent, both between trips in the same car and from one car to another. This additional guesstimate would just add more confusion.
Highway 70mph - https://insideevs.com/reviews/443791/ev-range-test-results/ Highway 75mph - https://www.caranddriver.com/shopping-advice/a32603216/ev-ra... Mix - https://www.edmunds.com/car-news/electric-car-range-and-cons...
It's a shame too because Tesla are towards the top of the the real world range pack, so they don't really have to lie.. but it's like a compulsion for some people.
What is mind boggling and hilarious is that there's a Porsche rated EPA 225mi and a Tesla rated EPA 348mi and they both end up achieving 280mi.
Notably the Model 3/Y seem to have a wider EPA-to-reality delta than the Model S in the 75mph test. This seems to align with my 4 year ownership experience. Tesla Model 3 LR rated 310mi but only hits 200mi with C&D. It's interesting how much the 3/Y range seems to drop from 70 to 75mph.
How can you know this without repeatedly running your car out of fuel?
My range is approx. 180 miles, in favorable conditions (summer, AC off). If it was actually accurate, as soon as you hit 70-80mph you would see your range half. Clearly that doesn't happen, so the estimator is off by ~40% for highway conditions, i.e. complete bullshit.
The precise estimate is in the navigation system, when you navigate to a destination and it says you will arrive with X% left. This takes into account speed, traffic, elevation, temperature, wind, etc. and is usually pretty accurate for me.
The golden number in a Tesla Is absolutely the navigation route estimate. While navigating you can open the Energy app as well to see more detail, how you are doing compared to the estimate, and specific factors affecting consumption.
I also just don't use navigation if I've been somewhere more than once. Just navigate with my head..
I use the navigation all the time, even when I know the way, because it knows about traffic jams and so I can get a good range estimate for longer trips. It even gives you a round-trip estimate back to your starting point.
Can you expand on this? You say etc, what else is included? Where is it documented that this calculation is actually happening, versus something far simpler?
https://www.tesla.com/ownersmanual/model3/en_gb/GUID-01F1A58...
Also if you open the Energy app in the car it will show you which of these factor(s) are contributing to higher or lower consumption than the navigation’s estimated range as you go.
I got 260mi range max on my 310mi rated car. If it was winter or a road trip in which I could truly go fast, it easily got below 200mi.
For a 310mi car, going to visit my parents or in-laws only 75mi away for Christmas should not have made me worry about making the round trip on one charge, but it frequently drained the battery below 20 or even 10%.
Any sane a Tesla driver changes that to show percent battery instead of range.
As others have said the trip planner is excellent, within a percent or two even in winter conditions driving over passes etc..
Note that range changes a lot more due to elevation, speed, cold etc, compared to gas cars because electrics are so much more efficient.
A percentage indicator is fine for a car you already have, but not useful for comparing between cars. It could show kWh, but that isn't good, either. What consumers actually care about is range, and whether that comes from more kWh, better aerodynamics, or a lighter car, the range is the bottom-line number. We wouldn't want consumers buying a car with a bigger battery just because it has more kWh if it doesn't get better range.
I think EPA-rated miles is the best of available options--it just needs to be understood by consumers. And I think cases where it isn't are a bit overstated. I suspect very few consumers genuinely believe they'll get the same range in miles regardless of their driving speed, headwinds, or whether they're going uphill or downhill.
Wind can easy be a 3mpg hit for my car, that’s about 10%. Not all the difference but a couple stacked effects could get yours
Annoying all these things matter when range is constrained. Next gen batteries can’t come soon enough.
True. But none of this should matter if your Tesla actually "learns", as other comments claim, right?
I'd like to see evidence of this, but I'm skeptical. Sounds like something Tesla fans claim is happening, like when you report an error at an intersection it gets fixed manually. And, even if true, I'm not sure how useful it'd be.
Do you like the BMW electric system?
When I recharge at home (using Level 2), the reported "full" values range from 28km to 44km. I cannot figure out why there is such a big range.
To make the efficiency more annoying, the BMW only includes a 16A charger (which is less than the old i3.) As a result you can only add ~3 range-miles per hour while charging, which makes public chargers basically useless (again compare to the LR Teslas which have 48A chargers and can do 40+ range-miles in an hour.) In gas-only hybrid mode, the mileage is ~19 MPG, which is actually kind of offensive for a hybrid car.
An EV is not an option for my lifestyle at this time. Once my 3 are out of car seats and/or strollers a sedan EV might work.
There’s always a Hummer EV or even cyber truck but that’s not quite my cup of tea.
EVs are showing that a lot of people do not know how to drive.
Also, another thing to consider is:
- Have you changed your tires? - Do you use max regen? - Do you use cruise control for the majority of your drive? - Do you drive over 75-80 MPH? - Do you have a roof rack?
It’s reasonable to ask for a range estimate that’s not naively optimistic.
Edit: Also a different algorithm when below 50% charged. As some of the replies point out, a destination does supply more information. The current charge level does not.
Obviously it will give a different estimate than stop and go traffic and starting the vehicle without pre-conditioning the battery.
Tesla does a great job with their scheduling functionality that lets you pre-condition battery before you leave and even when you near a supercharger to maximize charging efficiency of the battery.
As the article points out, it also switches to a significantly more accurate estimation once the battery is half discharged.
Are you implying its strange that the Tesla can calculate a more accurate range estimate when you literally tell it where you want to go to its computer which can use map data to calculate energy usage, versus you just driving around in circles in a arbitrary area and the computer only can assume based on EPA average usage?
It is clear from the discussion that it isn’t basing it on that at all. Would be overjoyed if it was based on average efficiency for the last 50 miles I drove. It isn’t.
Most ICE cars calculate range based on a long term average of a person's usage with some small amount of pessimism. Why should an EV do worse?
Eg. Having a window down, slope, number of passengers, etc.
Like, this is painfully clear to the drivers of this car vs what this article is suggesting.
And did anyone ever scrutinize gas vehicle tank estimates closely? I think one of the issues is the absolute lower range of EVs. You can feel it more when a 250 mile range is off than when a 400 mile range is off.
That said, I road trip in my Y all the time. Still hasn’t really bothered me. And I usually drive at 80 mph.
IMO product designers should not assume that the typical customer is a hyper-optimizer.
It’s not just an opinion. If you design that way, you’re misrepresenting truth for the vast majority of drivers.
Hard to distinguish that from lying.
The user will get more value out of any machine if they develop an accurate mental model of how it operates.
Knowing the best way to use something is not the same as serving it.
Physics serves no one. It is.
The car even defaults to showing %, rather than range on the top due to this exact situation.
Funny how somehow the millions who were “holding it wrong” were not holding the previous model wrong nor were holding the next model wrong.
And while all you’re saying about the driving range being affected by those factors is correct, if the car cannot accurately predict the range for this particular driver using some pretty simple historical data it should have then the Tesla’s shouldn’t display miles remaining.
Also if the elevation change is such that you don’t have enough to get to the top, the amount you would regen on the way down doesn’t matter.
> climbing a mountain and then going down the other side does cost more net energy than driving the same distance on flat ground.
You say this, but your reasoning is regen braking? What if you never had to brake the entire way? Where did all the energy going going up the hill go? If I carry a sack of sand up a hill and drop it, the amount of energy it has falling is equal to the amount of energy lifting it up the hill. Why does this then magically change when that sack of sand is now a car?
I do get if you're needing to ride the brakes a lot you'll get a pretty big impact on range, but a lot of grades wouldn't require that.
At the same speed, but if you don't break you likely won't have a constant speed. There's also motor efficiency, but that has less of an impact on electric vehicles because they are efficient over a high range.
Mechanical brakes do this by converting that energy to heat and brake dust.
Regen brakes do that by converting around 70% of that energy into battery storage to be used later.
Your sack likely does not roll down the hill with zero losses to friction along the way. The sack has the same energy as it did before you moved it, but it does not mean the journey consumed net zero energy.
Tip: tap the range estimate to switch it to percent. The EPA estimate is meaningless. Yes, that should be improved.
The estimates are based on driving on a flat road at the speed limit.
Even my Lexus SUV can get 24mpg driving on 35-45mph roads vs 16-19 in the city or going to the mountains where elevation increases.
People's understanding of range is just not quite there yet whether it's for an ICE vehicle or an EV.
I know how far % will go. Very simple.
The miles is a PR stunt.
That's not quite right. The power required to maintain a constant velocity v against a constant drag force of F is P = Fv. With air drag on a car moving at highway speeds, the drag force F actually depends on v: it's proportional to the square of v, i.e. F ~ v^2. All together then:
P ~ v^3
So doubling the speed will increase the required power by a factor of eight.
If the power is 8x higher and the speed is 2x higher then the energy per mile must be 4x higher, as he says.
You are correct that power lost to aerodynamic drag increases with the cube of velocity. However, if you increase speed, the time spent is reduced. As a result, the total energy grows with velocity squared.
Even this is a massive over-simplification. Driving the same speed with a 20 mph headwind is going to take lot more energy than with a 20 mph tailwind for example. There's lots of other variables and they may be certainly tracking some (like A/C current draw) but I doubt they track others (like rolling friction or road conditions).
Edit: I found this article [1] and it claims they track an impressive amount of weather and traffic data for the calculation. I'd be curious if this is based on car sensors (probably not?) or local weather stations.
[1] https://electrek.co/2022/03/16/tesla-accounts-wind-air-densi...
I’ve never driven a car to empty ever. I wouldn’t with a Tesla either.
Edit: someone else pointed out if you actually navigate then it will show remaining % more accurately. Still seems like false advertising..
How is the car supposed to know how much energy you might be using in the future?
Last time I checked, no ICE car has the ability to predict the future.
How is that different from what Tesla does.
>> as well as your current energy efficiency.
How is that different from what Tesla does.
It shows you current battery percentage, it shows you live on the default screen what its discharge rate is, it also tells you in a side screen what driving habits are consuming extra energy from baseline and percentages from doing things like driving over 70 mpg, air conditioning, altitude changes.
So what exactly is an ICE car doing better.
Last time I checked, my fuel gauge wasn't telling me about the 15% drop in engine efficiency from going to high altitude areas. Funnily enough, the Tesla showed a large increase in energy use due to going up a slop, but otherwise is not affected by the drop in air density.
Tesla COULD do that, but they don't on the main display because basing it on real data instead of garbage EPA data would produce a more conservative number and that would be harder to sell.
In my ICE car, all the places I can see range remaining have the same exact number, because doing anything else would be stupid and confusing.
FTA: Musk and two local executives did so in a June 19 statement, acknowledging “false/exaggerated advertising.”
Tesla - I literally never achieved the advertised range once. BMW - I exceed the advertised range during low-speed highway cruises in ideal summer conditions.
Tesla - the range it shows me in car (not in nav) is the never-achievable EPA range. BMW - the range it shows me in car (not in nav) adjusts ride to ride based on efficiency on most recent trips. So in the depths of winter it's showing me something 20% lower than in the peak of summer. This means it's factoring in driver behavior, drive mode used, speed, and temperature effectively.
It is reasonable to assume that your range on a trip is most similar to the range in your recent trips.
I can get in my BMW, look at the range meter, guesstimate the range on arrival and be correct to within 1% 9 times out of 10.
In my Tesla, I would constantly be doing mental math to discount the range it was showing me, to what I typically got, the weather, to see how big a delta it would be.
Sure, the nav range in Tesla got smarter over time and factored things in.. but this doesn't help on long round trips. It might tell me that I'm going to reach my destination with X% left, but I now have to do mental math to figure out if I am going to make it back or not.
With Tesla, I can't simply get in the car, see 300mi range on dash.. know I am making a trip 100mi each way so I'll be fine. Instead it's like - 300mi range, NAV says I'll have 58% remaining at destination.. OK so that means it's estimating X burn rate, which means I will make it home with... 17% instead of 33%.
Include weather, recent trips, lifetime consumption rates, type of road currently driving, etc.
Do anything other than the absolute simplest, laziest, most optimistic estimation which is "hey I bet you'll get the almost impossible-to-meet spec consumption rate!".
Can you tell more about this? I'm curious.
I do long road trips all the time with it. Best car I’ve owned ever by a mile.
Was driving back from a campsite that I turned out to not have charging compatibility with, but thought I had plenty of margin to get to the nearest charger. As I drove through the mountains however, I began noticing that a.) my battery was depleting much faster than expected and b.) I wasn’t seeing any houses and very few motorists. I watched with increasing dread as the trip miles began converging with the battery miles, as my friends in the car got more and more quiet. We reached the inflection point, and the best I could do was hope we’d encounter somewhere with a plug that might be able to get us the rest of the way. Eventually though the milage indicator reached zero, and I pulled off the road to what I thought was a campsite but turned out to be a sort of rest stop with no power plugs in sight. To make matters worse I was in a mountain valley and had no phone signal, and hiking wasn’t an option as it was pretty hot and we had no water. We were there for hours until I was able to flag down a nice older couple and get a ride to a place with cell signal, where I was able to get a tow truck capable of transporting my car (turns out you need one that has a full bed because of the regenerative breaking, and tesla’s service doesn’t have infinite coverage) to the charger I was trying to get to.
Ironically that last part was probably the most frustrating. The charging spot was full save one spot in the back, which my tow truck guy Mel couldn’t get back to. No sweat I thought, I’ll just try asking someone to swap, but people in their cars pretended to ignore me, and one couple leaving theirs just walked away, as I asked if they could move so we could unload my dead car. Had a sudden wave of empathy for the people I usually walk away from who ask me for spare change lol. Eventually someone left and I was able to charge and resume the 6 hour road trip home. Biggest lesson learned was that slow is fast, keep it at 60 if you want the milage meter to not die as quick.
The sheer ease of mind that comes with having densely packed energy that can be replenished at a moment's notice practically anywhere should not be disregarded easily. Maybe battery tech can get there some day, but it's certainly not today.
I have a very old petrol car (>35y) with a terrible fuel-indicator. I bring a spare 5L tank with petrol under the backseat always.
An EV could achieve the same with a small portable powerbank, not?
My current tank can hold some 50+L; this gives my old T3 a range of ~430km¹. When we lived in Botswana ('83, other car) we had an extra 150L spare fuel-tank instead of back-seats. We could do some 1500km in this old 4wd on full tanks. Which was needed as gas-pumps were easily 300km apart and often out of gas.
An EV could achieve the same with the back-seats replaced by additional battery-packs, not? I'd presume this might be too heavy or not allowed due to regulations, but technically just adding ridiculous amounts of batteries would solve this. Like adding ridiculous tanks for gas would.
Sure, the amount of joules you can pack in a KG of fuel is far more than in a KG of batteries. But to me the solution then is easy: just add more KGs.
¹yup, the mileage is terrible, a VW T3 is basically an underpowered, 1500kg brick
Better idea would be a mobile fast charging truck. Ironically that truck would have to be a diesel to make sure it had the range to support distant stranded vehicles, and not be insanely heavy and expensive itself.
Not too safe of an idea...
> An EV could achieve the same with a small portable powerbank, not?
Say that tank gets you 70km. You'd need 15 kilowatt-hours or 54 megajoules of battery, or about 56kg and about 25L of volume to do the same.
> An EV could achieve the same with the back-seats replaced by additional battery-packs, not? I'd presume this might be too heavy or not allowed due to regulations, but technically just adding ridiculous amounts of batteries would solve this.
Maybe, but it's also ridiculous amounts of money. Also, really increasing the mass of the vehicle is enough to hurt efficiency, so...
uHaul could make a killing off of them for people who want to take their EV on a road trip. If you could get 600 miles off of a single combined full charge you would be in the range of reasonable American road trip distance, and you could make the choice to stop and eat and occupy two chargers to get another 480 miles or so out of a 30 minute stop.
I usually clock about 900-1100 miles a day when I'm doing a destination road trip, so I would still chafe at that limit, but it would beat the heck out of sub-300 mile limits between long breaks for me.
Of course, this is in an ideal world where everything goes my way. I wonder if the penalty would be as high as 33%. Seems like it would be simple to make a maximally aerodynamic battery trailer since human comfort doesn't have to be considered. Then you're only adding the weight and drag of a few hundred lbs of trailer and battery.
I would think the penalty would be in the high single digits or at most in the very low double digits which could be offset by having 1.5x or 2x normal battery capacity in the trailer.
*Ninja edit, I decided to look this up. The Model Y's battery is 1700 lbs, so you are absolutely right that there would be a significant distance penalty adding that much weight to the vehicle plus the trailer weight and the battery armor as well if that isn't included in the weight.
https://www.carparts.com/blog/how-heavy-is-a-tesla-battery/
Curb weight of the Model Y is also 4400 lbs, so having to tow a 2500 lb trailer would be a significant hassle.
Perhaps that could be offset by making the trailer smart and adding motors to it that the main brain could control through the power link. If it could push its own weight and it had a 1.5x battery, and if it also had regenerative braking, then it could get close to doubling the distance.
Then again, each trailer would cost right about the same as a full vehicle, and would require an entire factory to be spun up to make them, and it would be an incredibly valuable product and therefore ripe for theft.
Lots of negatives, not a lot of positives.
It would be better all in all to be able to hot swap the batteries then. With standardized batteries put onto an integrated sled system, a robot at the fuel pump could pull the discharged battery and put it on a battery tester/charger and insert a fresh charged battery in its place.
I guess that would be more like an oil change or system flush, but the advantages would be manifold. Batteries wouldn't be the weak spot in the system any longer. The likelihood of people keeping batteries until they degraded would be significantly reduced, problematic batteries could be identified and repaired or recycled before they erupted, and assuming that the system was in wide usage it could enable road trippers to stay on the road longer quicker and waste less daylight.
Plus, for manufacturers, fuel stations, and mechanics, it would be an opportunity to make more money off of vehicle owners while providing safer, longer lasting vehicles to customers.
It's probably still a post-scarcity pipe dream though.
This has been discussed/proposed/Tesla said they were going to do this long ago.
The big downside is that no one wants to exchange their battery for someone else's. Pretty soon all the batteries end up in crappy shape.
The only way you could really do this is by having the swap stations own the batteries--- but this is so capital intensive that it's really a non-starter. Not to mention that it is a bit mechanically fraught.
The big upside is that we could use a lot more solar/daytime power for charging.
If the glass pack batteries make it to market, with their 2x capacity boost and lack of dangerous chemicals, it might make more sense, but purportedly they also work better with quick charge and can handle more charge cycles, so it may be a moot point anyway.
Also, why a battery trailer? Why not a gas tank plus generator trailer?
But I guess if you need it once every few years as opposed to daily, it's ok.
(According to a random source on the web, a Model Y battery weighs 1,770 pounds, so a perfectly efficient 5%-size physical battery would add another 88 pounds to the cargo.)
That is already how it is done on all EVs. malwrar should have kept driving.
Playlist of tests. https://www.youtube.com/watch?v=OIi_8OXfLeg&list=PLqKx2qnB8X...
Your car probably has a 2.4 gallon tank, but it's been electronically limited to 1.9 gallons.
and the most disappointing.
This also works in petrol cars: the air resistance efficiency falloff is dramatic at higher speeds.
My dad told a story once where he was driving out west borrowing one of his brother's cars with a broken speedometer. After he got back he said to his brother, "the car just seemed to top out at a certain point" and his brother said "yeah, that's about 85 mph" (the national speed limit was 55 mph at that time). So at 85 mph the air resistance equaled the force the engine could apply and the car wouldn't go any faster.
First, the force that is proportional to the square of the speed is the drag force, which means it's the force you need to supply just to keep the speed from dropping. Power = force * speed is a different "force" - it's the force produced by the engine.
Second, power output of an engine typically has an RPM where it peaks. Past that point, more speed means less power output, which means much less force output, because the force is the power divided by the speed. But force needed still increases as the square of speed.
Suppose you have a vehicle w/ 3 m^2 frontal area, drag coefficient of 0.3 and it's travelling at 30 m/s. Using this calculator https://www.symbolab.com/calculator/physics/drag-equation you can find that will require about 500 N of force (use density of 1.225). The power at that operating point is the product of speed and force, or 30 m/s * 500 N = 15 kW.
Now let's change the speed to 40 m/s. That bumps the force to about 900 N. Now we would calculate power as 40 m/s * 900 N = 36 kW.
Changing these numbers to horsepower we get 20 hp and 48 hp.
The force goes with the square, the power goes with cube. There are assumptions here - for example, if you have a headwind this statement is no longer true because the speed in the drag equation is the air speed of the vehicle (goes up with headwind / down with tailwind) but the third speed factor is the ground speed of the vehicle (because that's based on the physics "work is equal to force times distance" and power is the rate of work).
The graph of an internal combustion engine's power at wide-open throttle vs. engine speed is irrelevant, unless you are trying to figure out which gear ratios would let the engine make enough power to drive the vehicle under those conditions.
You don't see that much these days, though, as having your highest gear that short is just leaving fuel economy on the table on the highway. If you can pick up speed going uphill without changing down at least one gear, you're wasting fuel to pumping losses on flats/downhill.
EVs (and hybrids) with regen braking remove this lost efficiency in city driving, leaving you with an energy usage curve that scales more directly with aerodynamic drag due to speed.
EVs are more efficient at low and high speeds than ICE, they just have small “gas tanks” so the high speed losses are more noticeable.
Also some cars have independent heating that can be used to heat up the car up without running an engine. Not sure how exactly it works but I think it uses special battery.
AC compressor of course takes a lot of power.
Ford also seems to offer them as an option (e.g. as part of the cold weather package)for a number of their straight ICE vehicles like the Bronco sport, Escape, or F-150.
I would guess system like this would be rare in US, because you are allowed to have remote start on your cars.
edit: never mind, it burns fuel https://www.auditech.org/acont-1427.html
I never thought I'd see the return of the gasoline heater. I wonder if its offered in the states.
This is one of those stupid facts that lives rent-free in my head. "If you want 'dry' hot air you need to dry it before sending it to the heater. The primary purpose of the A/C is to dry the air(this also happens to cool it), there is already an A/C unit in the ductwork, profit" But I decided to fact check myself and was not able to find much information. I did find one page that said this mainly occurs on the "defrost" setting, which makes sense as this is what is used when you don't want your windows to fog.
If your engine is overheating, one of the things you should do is turn the heater on max.
Just out of curiosity, where was this?
Tesla owners to other Tesla owners:
> people in their cars pretended to ignore me
Sounds incredibly short-sighted that the regenerative braking can't be temporarily disabled by the driver... two people can push a "regular" car to a nearby gas station in a pinch. Even one person can push a smaller car around a parking lot if necessary.
That said, they often send out full/flat bed tow trucks these days for almost any reason.
Edit: fixed "breaking" to "braking"
Wouldn't a clutch be unnecessary in this case... a complete disconnect from the drive train should suffice, no?
What I'm wondering now is, if "free roll" mode is activated while I'm at a red light... is there a chance I start rolling as I do in my manual when I take my foot off the brake?
Maybe I should just reach out to Tesla at this point though (-:
Isn't this exactly what regenerative braking is? There's no mechanical disconnect between the wheels and the motor (i.e. a clutch) so pushing the car essentially turns it into a generator.
Inside the motor/generator, what happens is that if there's current flowing in the windings as a result of the EMF induced by turning the rotor, then, loosely speaking, it creates a magnetic field which opposes the rotation - but if it is not connected to some load (or a short-circuit) there's no current, even though there is still an induced EMF.
It's a standard case of the conservation of energy - if it were not the case, you could put an arbitrary number of generators on the same shaft, all supplying power to external loads, and then use the output of a couple of them to power a motor spinning the assembly...
If you are turning a motor/generator slowly, then the difference in torque is not much, but I am responding to the implication that the motor would have to be mechanically disengaged in order to disable the braking effect.
And, off the top of my head I'm going to say the manual locking hubs will be better overall. Better from an energy efficiency perspective as well as overall convenience and simplicity of design. They might be worse for Tesla's P&L though since anyone with a tire jack and a standard parts dealer nearby could work on the car.
Then again, besides the fact that I'm a cynic... what the heck do I really know!??!
The ability and need to push a car is incredibly common, especially for emergency or non-optimal scenarios. Cars often stop working, be it dead battery, out of gas, malfunction, broken axle(which teslas have).
If a car runs out of charge or malfunctions, it would help everyone if it is easier to move it so it doesn't block traffic. It might be wise to make this a requirement. Seems to me that a clutch that simply switches between connected and neutral and that only operates when the car isn't moving would be far simpler and cheaper than a clutch that handles shifting between different gears while the engine is turning.
standards and automatic trans have neutral that disconnects driveshaft from engine, removing any resistance from the engaged gear. Most EVs either don't have neutral or a poor implementation of it, because of single gear transmission/direct drive.
I'm sorry, do you mean that neutral and "car wash/freeroll mode" are not 100% equivalent?
This really confounds me... if my car has a problem while driving down the road, I'd really like to have a chance of pushing it onto the shoulder if necessary.
A car that you can't do this with sounds very poorly designed to me.
This is fine for low speeds and short distances but is not advised for towing, like with tow trucks that leave two of the car’s wheels on the ground.
Wouldn't that be ok since the parent's root problem was no cell-phone signal?
Edit: of course walking is an option too :-)
I read the above as an indication that they were in a valley where mountains were blocking any chance of a signal. Going further "downhill" wouldn't help in that case.
This Tesla must've been in one heck of a stop where "hiking wasn’t an option as it was pretty hot and we had no water", lol. Does Tesla make a motocross bike?
The weight of a Tesla is not some unprecedented figure for a passenger car - a model 3 is no heavier than many BMW 5 series configurations etc.
The far bigger problem for pushing EVs in my experience is blown pyro-fuses that lock the axle after crashes preventing the wheels from turning - a common issue after an EV shunt. This is why you will often see EVs "dragged" out of shunts by the recovery vehicle until they can get the locked wheels onto dollies. This is only an issue if the EV being pushed has been in an impact generally, but the bar for a pyrofuse blow seems to be low too - it will trip even if airbags haven't deployed. The wheels on many EV motor axles wont turn again until the pyrofuse is replaced.
This was mentioned a little earlier and further down in the comment tree but many thanks to you too for clearing this up.
I just read about this feature which is advertised purely for car washes, and can be gotten into with a wierd combination of actions or "putting the car into neutral".
Is it...not just going into neutral via disconecting a drive shaft?
Conceptually you are correct its like neutral, but almost no EV from any manufacturer has disconnecting drive shafts. Every Tesla model except the original roadster is locked in a single gear transmission that never disconnects - one of the big reasons EV drivetrains can be built so reliable with virtually no maintenance requirements (there is no service items on most EV drivetrains until a quick coolant flush in ~10th year of car's life span).
The Model 3/Y just dump the output of the rotor into a permanently locked 9:1 trans. There is no need for a reverse gear either as unlike a gas engine the electric motor can easily rotate in both directions.
An electric motor cant "stall" like a gas engine and generally never has to change gear, so there is usually no real benefit to fitting the cost and complexity of clutching driveshafts you typically need when you have a gearbox or gas engine.
Someone will correct me if I'm wrong, but to best of my memory the only "mainstream" EV with a gearbox on sale today is the Porche Taycan/Audi E-Tron GT (they are both the same chasis/drivetrain underneath) with its pretty unusual 2-speed setup. I wouldn't be surprised at all if the next generation of that car eliminates the gearbox.
Very good point and although IDK how it's done I completely agree with you regarding the terminology. In other words, I don't see new internal combustion cars renaming neutral to be "car wash mode"... lol.
Cars should have neutral. And, if yours does then it should be named as such.
Making sure I've got "car was mode" is not what I want to do when I'm in the market for a new car. Nor do I want to start reading through the owners manual should I have to push my car onto the shoulder of the road in an emergency.
Perhaps my age and crotchety grumpiness is starting to show.
Is that possible when the car is persumed dead? Or why would you be trying to push it otherwise? If you can enable free-rolling wheels, why not just drive away?
I think AWD Teslas have an independent motor and drivetrain for the rear wheels. Naively, one would expect that if you unload the rear axle motor/generator you could just tow the car with little resistance and no damage, but in practice the picture is probably more complicated. I would love to hear from an expert.
Controls > Service > Car Wash Mode And then "Enable Free Roll"
Nonetheless, I'm a rather conservative type of person and see your point so in my "dream car" I might want a way to manually put the car in neutral (or free-roll mode, whatever you want to call it). That's why locking hubs came to my mind in a prior reply.
Wanting to prewarm without planning a trip I understand. It would be use to be able to prwarm for regular charging or non-supercharger charging too.
If anyone know, I'd be interested in the more details and what led to that decision.
When you take it into the mountains, it's not surprising that your gas gauge goes down a bit faster when you're pushing that gas pedal a little further than usual.
Perhaps the takeaway is that EVs shouldn't so prominently display the range as part of the "gas" gauge the way they tend to do.
When we left, estimated range was 45% on arrival. We arrived with 27% range. Granted, we did encounter a crapload of traffic, but the Nav system took that into account because the time was accurate.
I don't fully fault Tesla for the range inaccuracy; an ICE car would probably have had a similar issue. But it's not as smart as I thought it was, which is a shame.
This goes to the optimistic/ exagerated calculation
Related to my other comment, it may be more difficult if it’s relying on weather station data rather than local car sensors though.
Another take-home lesson: if you're driving out of range of civilization, carry water along with your first aid supplies.
If you're in an emergency and your phone says you have no signal, call 911 anyway. It'll attempt to reach any network in range that the phone is compatible with, not just the network you're subscribed to. Some phones nowadays will show "Emergency calls only" when this is the case, but it doesn't appear to be 100% consistent, so again, call anyway.
Also turn on battery saver and when you're not actively trying to call, keep the phone in airplane mode. If you don't it'll repeatedly try to reach a tower which will drain your battery quickly. Don't power it off unless you don't plan to use it for the rest of the day, because booting up uses a lot of energy.
Is there a service for "On demand battery charging". A mini truck carrying a generator that can be called to the location. Could charge premium from the EVs that are too tired to move.
[0] https://www.motorcycleclassics.com/classic-motorcycle-tourin...
I'm uncomfortably aware how quickly vehicles take me to inconvenient, if not dangerous, distances. 10 miles away is a short distance to drive but three hours to walk. Even fifteen minutes on a bike is a tedious walking distance back if it breaks down. For how easy it is to put or keep some bottled water in a car, why not do that all the time?
This seems incredibly irresponsible when people could die from being stranded when the meter lies about being able to get home like the other commenter described.
Seems like so many Tesla owners drive like complete jerks.
Drive way too close to people (tailgating).
Drive way too fast all time, even in neighborhoods.
Drive way too aggressively.
Drive way too entitled.
I’ve seen some crazy stuff from people driving a Tesla. Driving on the shoulder when traffic backs up. Zipping around people to steal parking spots.
Tesla owners posting videos online of anyone that walks by their car.
We won’t park near a Tesla at all these days for fear of being posted online or even those within Tesla passing it around.
2) male drivers
3) intelligent drivers that think rules don't apply to them (see: HACKER news)
4) affluent drivers, a lot of the BMW crowd
5) single drivers (if you have a kid, you slow down in general)
I wonder if they would have started responding if you motioned the tow truck driver to unload your car directly behind them, in a position that would obviously seriously inconvenience the other driver(s) or prevent them from leaving entirely...of course, also mentioning that was your plan to them loudly so you're sure they can hear.
Maybe the non-bed truck could've simply charged your car by pulling it :D
towing a car with regenerative braking seems like a great way to charge it! Elon needs to put somebody on this.
Sunk cost and all that
The battery icon is Miles of rated range, where “rated” means flat windless road at 60MPH and 70 degrees. Call it “standard” range if you will. The car has no idea where you’re going so it uses the standard calculation.
When you set a destination it can now (and does) factor in elevation change, speed on given roads, wind speed, wind direction, temperature along the route, etc etc etc and is more accurate.
So your least favorite feature is one you openly admit to not using properly? If you want laser precise range estimation set a destination ffs. Or, if you’re like most drivers you start every day with 200-300mi of range and unless you’re going out of state you don’t even think about range.
The thing I hate most about my car is that I spent $10K on "Full Self Driving" and rarely use it. It totally sucks and is definitely the worst $10K I've ever spent on anything. That money could have gone to a nice vacation somewhere and I would be happy about that. But no, every time I try out the FSD, I come away disappointed.
Also, I didn't realize how many restrictions there would be. You have to keep your hands applying constant tension on the steering wheel, and there's actually a camera that watches your eyes now. So you can't even eat a sandwich without the car freaking out and punishing you for looking at your food too long.
It's awesome!
ICE cars all show a percentage, and maybe additionally a mileage on newer cars. The fact that they threw that away is a little silly.
You state this as a fact, but it's completely incorrect. It has been an option since at least 2018 to change the indicator to percentage.
On the way back to the drop off autopilot tried to slam us into the Bentley next us! It had been traveling the same direction as us for like 20 minutes and when we passed through an intersection it just jerked hard left and I had to correct it manually. Possible injuries notwithstanding I’m sure that would have surpassed my insurance coverage, which I’ve intentionally gone way above minimums on.
Even if this and many other stories are just anecdotes, I could never imagine myself even testing this "auto-but-not-really-pilot" feature outside of a testing environment.
How do you folks dare to even try to use it? The risk is so big and the reward so tiny...
But after that no thanks.
Where were you that has a dozen chargers but no superchargers?
One other thing, for days on end the navigation would never “engage” just stuck on something like “Starting route.” So it never started conditioning the battery on the drive (and even chastised me for not doing so!?)
Finally, one morning all miles measurements were replaced with kilometers and it took watching a youtube video to figure out how to change it back.
Not owning a car only using rentals, I still think Tesla has the best and most intuitive UI. I can find everything easily, whereas in a SUVs from Skoda/VW/Audi/BMW/Renault/... it's hard to find things - at least for me.
What I do hate about the Model Ys we rented is the noise! Wind/wheel noise is as loud at 100km/h as a BMW at 150km/h - I guess they do this to safe weight and increase range, but it makes the trips very unpleasant.
Also how it randomly breaks in self driving (at least on a German Autobahn).
I think the best UI was before all the computer displays in cars. Everything operable without visual contact.
All that without the benefit of tactile feedback of knobs and switches.
Or, you know, margins.
Coasting on a flat surface at 35mph with a positive tailwind?
By convention, you are required to phrase this as "I love my Tesla, but..."
It sort of learns based on the immediately previous drive what the driving style is, and therefore what the range is.
but I have driven 35mph on slow city streets to make it to the next charging station when the one I was at was full with a line. (years ago)
I wish Tesla would allow you to hide the battery percentage entirely (unless it drops below a threshold).
Worth noting this is also common in ICE cars. Mine has it.
Interestingly the accuracy seems to get a lot better by the time I'm down to half a tank. I don't know if it's a sensor issue, or maybe my driving habits just change a lot when I have a full tank versus when I'm running low.
The type of driving and time I'm driving can also make a huge difference to my trip MPG - some trips I average about 10MPG, others closer to 40MPG. Generally speaking, low speed but clear rural roads get the best, followed by motorway, followed by pootering around the city. The absolute worst mileage is during the winter, when I might only be driving lots of short trips around town on a very cold engine, with the headlights on, in the rain. In that case, I might only get around 200 miles out of a tank.
Anyway, my point is that knowing the specifics of this trip's fuel consumption is a much easier problem than knowing how many miles it'll be until you next need to refuel.
However, the key difference is that my gas car can be filled up anywhere, and worst case I'd need to get a gas can. Running out of charge is a flatbed tow, that's a huge hassle. The range being accurate is a big deal on an electric!
Still more of a pain than a petrol can but better than a flatbed!
Range was horrible. We drove about 100 miles and spent a couple hours over several sessions at superchargers. The handling and turning radius sucked. The controls were frighteningly distracting and confusing. Sound in the cabin seemed very weird, probably due to the glass roof and noise cancelling system. Finally, for a dual motor, I expected a lot more acceleration. I drove a Chevy Bolt for a year and was surprised how heavy and sluggish the MY felt.
We ran the A/C most of the time. I was driving pretty conservatively with about 50/50 highway/city streets. I did try to show off the acceleration abilities once but didn't fully floor it. It's possible that, being a rental(although fairly new) the battery had taken some charging abuse.
Honestly I don't believe this. Requiring two hours sessions in 100 miles is an absolutely extraordinary claim, requiring something to be extremely wrong with the car in some way that didnt brick it entirely.
I now own a Long Range Model X. It is MUCH closer to the EPA mileage. I average ~330wh/m but I have a 100kwh battery, so much closer to a legitimate 300 mile range. Once again, doesn’t really make a different unless you happen to have an exact 275 mile trip. Either way, you’ll be stopping at a halfway supercharger to stay in optimal charge range (15-85%).
https://www.youtube.com/watch?v=6LWL90paufE
https://www.youtube.com/watch?v=ynCaTDR4rDQ
https://www.youtube.com/watch?v=eFB6hsYXDiA
https://www.youtube.com/watch?v=fvwOa7TCd1E
Spoiler alert: Tesla models fare about as well, if not better, than their EV cousins, hitting around 80% of the stated range in the wild.
This is not true according to the very article we're discussing here, which across many analysis learned that three Tesla vehicles were the least-accurate (most-optimistic or most-deceptive, depending on your point of view).
Otherwise it looks to me that your rant is just for karma collecting.
Judging by this the EPA numbers it gives are accurate on average.
Consider:
- batteries lose, best case, about 10-20% of max range over a typical car ownership period
- not charging to the max is very often important to not getting bad degradation, so take another 10% off
- winter can take 10-20% range off
- driving at typical speed as opposed to the alleged ratings is probably another 10-20% reduced range
- headwinds, air conditioning/heating, and other factors can remove another 10-20%.
So suddenly, some 300 mile rated range is actually 150 miles of real world range. So here in the midwest, with underinvested charging infrastructure and biiiiiiggggg states and rural density, a 400 mile range really is pretty much required for any functional long distance driving.
However if you punch in a destination, you'll get exact numbers, and those are insanely reliable. It claims (and I don't believe any claims coming from tesla) that it'll factor wind, elevation, temperature, etc. But regardless of what it factors in, it's on the money.