4 ms·

Not defending Tesla but battery range is really hard without context. Kinetic energy is velocity^2, which means moving twice the speed takes 4X the energy. They

Not defending Tesla but battery range is really hard without context. Kinetic energy is velocity^2, which means moving twice the speed takes 4X the energy. They probably can get the right estimate for a destination because it knows the speed limit for the route and using that as your velocity can give you a better answer.

cevn 3y ago
They could, but they don’t. Edit: someone else pointed out if you actually navigate then it will show remaining % more accurately. Still seems like false advertising..
- tekla 3y ago
  How is it false advertising.
  - cevn 3y ago
    I don't use navigation, almost ever, after the first place I go somewhere. Therefore, the main battery estimator is just wrong. If it actually worked, as soon as you got to highway speeds you would see it half. Hiding the real estimation behind the navigation tool is cowardly
    - tekla 3y ago
      How is that any different from a ICE car? 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.
      - brazzledazzle 3y ago
        The distance left in the tank is closer to the Tesla's more accurate estimate because it's constantly adjusting based on both your current gas level as well as your current energy efficiency. It may not accurately convey the distance available at the start of a trip but you're going to know well ahead of time if you're burn rate is too high. If the non-navigation distance estimate in a Tesla is always padded you could find out well after it's too late to make it to your destination or a charging station.
        tekla 3y ago
        > The distance left in the tank is closer to the Tesla's more accurate estimate because it's constantly adjusting based on both your current gas level 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.
        tshaddox 3y ago
        I wonder if anyone has actually objectively measured accuracy of various car models under various driving patterns. It seems plausible to me that everyone just thinks their ICE car is more accurate because 1) gas stations are literally everywhere so there is never “range anxiety” and 2) no one routinely lets their gas car get close to empty anyway.
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      - mrguyorama 3y ago
        In my ICE car, if I drive around the town getting 28mpg, the "range" trends downwards to reflect the poor efficiency, while if I drive a certain route where I get 42mpg, the "range" meter will reflect that. It uses a quite long rolling average 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.
  - crypot 3y ago
    It is false advertising. FTA: Musk and two local executives did so in a June 19 statement, acknowledging “false/exaggerated advertising.”
    - tekla 3y ago
      Link
      - crypot 3y ago
        You just have to click the title of the thread and it will take you to the Reuters article and you will be able to read the entire story.
- deleted 3y ago
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- hypnoosi 3y ago
  Its not false advertising, perhaps you could make a case of inaccurate ... but that's just advertising? You are not giving the car the context to provide an accurate estimate. Also you driving style might affect the estimate?
- steveBK123 3y ago
  Having owned a Tesla and non-Tesla EV the approach to range is entirely different. 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%.
  - cevn 3y ago
    Exactly. Doing all this math when the main estimator says X is exhausting. Obviously I use percentage now but there is a problem with that estimate and a lot of people just want to pretend everything is fine.
    - steveBK123 3y ago
      Right, make it a toggle in menu - dashboard range estimator: [spec/pessimistic/optimistic]. 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!".
bumby 3y ago
>They probably can get the right estimate for a destination because it knows the speed limit 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-density-range-calculation/ https://electrek.co/2022/03/16/tesla-accounts-wind-air-densi...
- johntiger1 3y ago
  Does all this somehow not apply to ICE vehicles? Cause the gas meter/range estimate was pretty accurate in my dad's '93 Corolla...
  - bumby 3y ago
    Of course. YMMV (literally), I suppose. My ICE Nissan seems highly variable while my SO's Ford seems pretty accurate. Maybe it's just the difference in driving habits :-)
  - LegitShady 3y ago
    The mileage you and your dad got was probably pretty significantly different based on driving style, location etc. Just accelerating quickly off stops can end up having a noticeable effect on overall mileage. You were just willing to accept a much less accurate and imprecise number as “pretty accurate” and when the fuel went down too much you filled it anyways. I’ve never driven a car to empty ever. I wouldn’t with a Tesla either.
troymc 3y ago
"...moving twice the speed takes 4X the energy..." 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.
- sebzim4500 3y ago
  Aren't you agreeing with him? If the power is 8x higher and the speed is 2x higher then the energy per mile must be 4x higher, as he says.
- ooterness 3y ago
  Power is energy power unit time. 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.
zeroonetwothree 3y ago
It’s more relevant how much you need to accelerate, not just your velocity. A satellite in orbit uses very little energy even though it’s going very fast.
- localhost 3y ago
  A satellite in orbit uses the energy imparted by the gravitational force of the Earth to stay in orbit (and very little to no drag depending on the altitude).
  - Retric 3y ago
    Gravity doesn’t add energy to satellites in orbit. It changes the direction of motion but not the velocity. In effect it’s no different than rotating a solid object where electromagnetism keeps all the atoms in the same relative position.
rtkwe 3y ago
KE is not 4x the energy continuously used though that's 4x the energy spent getting to that speed. Air resistance does also square with velocity and that is an amount that's constantly required to be spent to maintain that speed.

cevn 3y ago

They could, but they don’t. Edit: someone else pointed out if you actually navigate then it will show remaining % more accurately. Still seems like false advertising..

tekla 3y ago
How is it false advertising.
- cevn 3y ago
  I don't use navigation, almost ever, after the first place I go somewhere. Therefore, the main battery estimator is just wrong. If it actually worked, as soon as you got to highway speeds you would see it half. Hiding the real estimation behind the navigation tool is cowardly
  - tekla 3y ago
    How is that any different from a ICE car? 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.
    - brazzledazzle 3y ago
      The distance left in the tank is closer to the Tesla's more accurate estimate because it's constantly adjusting based on both your current gas level as well as your current energy efficiency. It may not accurately convey the distance available at the start of a trip but you're going to know well ahead of time if you're burn rate is too high. If the non-navigation distance estimate in a Tesla is always padded you could find out well after it's too late to make it to your destination or a charging station.
      - tekla 3y ago
        > The distance left in the tank is closer to the Tesla's more accurate estimate because it's constantly adjusting based on both your current gas level 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.
      - tshaddox 3y ago
        I wonder if anyone has actually objectively measured accuracy of various car models under various driving patterns. It seems plausible to me that everyone just thinks their ICE car is more accurate because 1) gas stations are literally everywhere so there is never “range anxiety” and 2) no one routinely lets their gas car get close to empty anyway.
        deleted 3y ago
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    - mrguyorama 3y ago
      In my ICE car, if I drive around the town getting 28mpg, the "range" trends downwards to reflect the poor efficiency, while if I drive a certain route where I get 42mpg, the "range" meter will reflect that. It uses a quite long rolling average 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.
- crypot 3y ago
  It is false advertising. FTA: Musk and two local executives did so in a June 19 statement, acknowledging “false/exaggerated advertising.”
  - tekla 3y ago
    Link
    - crypot 3y ago
      You just have to click the title of the thread and it will take you to the Reuters article and you will be able to read the entire story.
deleted 3y ago
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hypnoosi 3y ago
Its not false advertising, perhaps you could make a case of inaccurate ... but that's just advertising? You are not giving the car the context to provide an accurate estimate. Also you driving style might affect the estimate?
steveBK123 3y ago
Having owned a Tesla and non-Tesla EV the approach to range is entirely different. 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%.
- cevn 3y ago
  Exactly. Doing all this math when the main estimator says X is exhausting. Obviously I use percentage now but there is a problem with that estimate and a lot of people just want to pretend everything is fine.
  - steveBK123 3y ago
    Right, make it a toggle in menu - dashboard range estimator: [spec/pessimistic/optimistic]. 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!".

bumby 3y ago

>They probably can get the right estimate for a destination because it knows the speed limit 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-density-range-calculation/ https://electrek.co/2022/03/16/tesla-accounts-wind-air-densi...

johntiger1 3y ago
Does all this somehow not apply to ICE vehicles? Cause the gas meter/range estimate was pretty accurate in my dad's '93 Corolla...
- bumby 3y ago
  Of course. YMMV (literally), I suppose. My ICE Nissan seems highly variable while my SO's Ford seems pretty accurate. Maybe it's just the difference in driving habits :-)
- LegitShady 3y ago
  The mileage you and your dad got was probably pretty significantly different based on driving style, location etc. Just accelerating quickly off stops can end up having a noticeable effect on overall mileage. You were just willing to accept a much less accurate and imprecise number as “pretty accurate” and when the fuel went down too much you filled it anyways. I’ve never driven a car to empty ever. I wouldn’t with a Tesla either.

troymc 3y ago

"...moving twice the speed takes 4X the energy..." 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.

sebzim4500 3y ago
Aren't you agreeing with him? If the power is 8x higher and the speed is 2x higher then the energy per mile must be 4x higher, as he says.
ooterness 3y ago
Power is energy power unit time. 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.

zeroonetwothree 3y ago

It’s more relevant how much you need to accelerate, not just your velocity. A satellite in orbit uses very little energy even though it’s going very fast.

localhost 3y ago
A satellite in orbit uses the energy imparted by the gravitational force of the Earth to stay in orbit (and very little to no drag depending on the altitude).
- Retric 3y ago
  Gravity doesn’t add energy to satellites in orbit. It changes the direction of motion but not the velocity. In effect it’s no different than rotating a solid object where electromagnetism keeps all the atoms in the same relative position.

rtkwe 3y ago

KE is not 4x the energy continuously used though that's 4x the energy spent getting to that speed. Air resistance does also square with velocity and that is an amount that's constantly required to be spent to maintain that speed.