6 ms·

Driving Range for the Tesla Model S Family

46 points by brbcoding 12y ago

Fuzzwah 12y ago
I tried the range calculator but it doesn't let me compute expected range for driving 75 mph on a highway on a 120 degree F Arizona summer day..... Not to mention the 85 mph most people actually sit on.
- mikeyouse 12y ago
  Driving any car at 85mph will nuke the mileage.. DOE figures for 80mph vs. 55mph show a 30% reduction in mileage, so I'd imagine 85mpg is more like a 35% reduction. Given that MPG isn't a direct linkage, it's worth noting that this will roughly double your driving cost per mile depending on the car.. http://www.fueleconomy.gov/feg/driveHabits.jsp http://www.fueleconomy.gov/feg/driveHabits.jsp
  - mbell 12y ago
    I would imagine the DOE numbers are some sort of average. Considering how un-aerodynamic the average US car is I would guess that number isn't terribly accurate for a vehicle like the roadster.
  - nnethercote 12y ago
    You don't have to guess. The linked article has two graphs showing the range obtained at speeds ranging from 40 mph to 85 mph for different models. For the 85 KWh battery pack going at 55 mph you'll get about 350 miles of range. Going at 85 mph you'll just over 200 miles of range. That's slightly more than a 40% reduction.
TrainedMonkey 12y ago
"the dual motor Model S will quickly torque sleep a drive unit when torque is not needed and instantly wake it up as the accelerator is pressed to command more torque." I can't understand this, is first torque meant to be toggle?
- sp332 12y ago
  "Torque sleep" just means the unit stops producing torque for a while.
- dmckeon 12y ago
  Torque sleep sounds like the electric motor equivalent of free-wheeling: https://en.wikipedia.org/wiki/Freewheel https://en.wikipedia.org/wiki/Freewheel
- TD-Linux 12y ago
  Tesla cars use induction motors. The rotors of an induction motor don't supply their own field, but need to be excited by current in the stator, which requires power. In addition, once there is a field, it produces hysteresis losses proportional to the speed of the motor. If the motor is completely off, the losses from freewheeling are very small. Cars based on permanent magnet motors do not need to use power to maintain the rotor's magnetic field. On the downside, the field cannot be shut off, so they always have hysteresis loss and cannot freewheel as nicely as induction motors can.
deleted 12y ago
[deleted]
portman 12y ago
The most under-reported aspect of driving a Tesla is how severely topography impacts range. Under normal conditions, I use 350 Wh/mi (watt-hours per mile). This is 17% more than "rated range" because -- and this is a technical term -- I drive like a madman. However, when driving to Tahoe (7000 feet higher), I end up using 850 Wh/mi: over 2x higher electricity consumption, because mountains. All this talk of tires and wind resistance is a red herring for topography, which does more to limit/extend range than any other factor. What's more, this could be so easily addressed with software: when I input my destination into GPS, the car should tell me my expected range. It knows the topography. Use the force, car! Taken one step further, since Tesla is constantly transmitting telemetry to home base, Tesla HQ likely knows the average battery consumption of all other drivers who have ever driven that route. This would allow non-topographical variables (traffic lights, potholes, road conditions) to be factored into the range calculation as well. Edit: Mistakenly used kWh/mi instead of Wh/mi units. Hat tip to Tarrosion for the correction.
- hamburglar 12y ago
  I've noticed this, too. I have a plug-in prius, which only gives you about a 10 mile electric range, so the game ends up being "can I make this trip to X and back without having to burn any gas?" Knowing the terrain in your neighborhoods and knowing the paths that don't involve a lot of elevation change can really make a big difference in whether you "win" this challenge.
- greglindahl 12y ago
  All cars use more energy to climb hills. If you'd like to factor that into your Tesla planning, check out https://evtripplanner.com/ https://evtripplanner.com/ -- It shows the Vacaville/Truckee segment as taking 173 rated miles to cover 130 actual miles.
  - rconti 12y ago
    It's worth noting also that he's not talking about "driving in hilly terrain", the original comment is talking about driving almost exclusively uphill. Going to Tahoe you'd go from somewhere around 0ft to around 8500ft depending on the pass, and then down only to 6200ft. Of course, this will impact all cars, though I find only a few MPG difference in our vehicles driving up to the ski resorts around Tahoe. One curious thing I've noticed is that my relatively-high-Torque-and-HP car with a manual transmission gets almost the same mileage on flat ground versus going up and down mountain ranges, assuming there's no net elevation gain. My girlfriend's fairly underpowered Subaru with a 4 speed automatic does significantly worse in the hills than it does on flat ground. Also interestingly, the Tesla should get significantly better mileage in thinner air (on flat ground) where a gas-engined car has to deal with less air to burn which balances out the lower wind resistance. Would also be interesting to see how the elevation change would affect a tesla at net 0. Say, drive from Sacramento to Truckee and back; I think the range should be plenty.
MrFoof 12y ago
Quick note: These ranges probably assume a 100% charge. Although this should be obvious, it should be noted that the Model S does not charge to 100% by default. By default it charges to 80%. This can be overridden by the user (in preparation for long trips), though after a few days it reverts back to the 80%. This is the improve the overall durability of the battery -- that is, the maximum capacity remains higher for longer if the battery is not fully charged every cycle.

46 points by brbcoding 12y ago

I tried the range calculator but it doesn't let me compute expected range for driving 75 mph on a highway on a 120 degree F Arizona summer day..... Not to mention the 85 mph most people actually sit on.

mikeyouse 12y ago
Driving any car at 85mph will nuke the mileage.. DOE figures for 80mph vs. 55mph show a 30% reduction in mileage, so I'd imagine 85mpg is more like a 35% reduction. Given that MPG isn't a direct linkage, it's worth noting that this will roughly double your driving cost per mile depending on the car.. http://www.fueleconomy.gov/feg/driveHabits.jsp http://www.fueleconomy.gov/feg/driveHabits.jsp
- mbell 12y ago
  I would imagine the DOE numbers are some sort of average. Considering how un-aerodynamic the average US car is I would guess that number isn't terribly accurate for a vehicle like the roadster.
- nnethercote 12y ago
  You don't have to guess. The linked article has two graphs showing the range obtained at speeds ranging from 40 mph to 85 mph for different models. For the 85 KWh battery pack going at 55 mph you'll get about 350 miles of range. Going at 85 mph you'll just over 200 miles of range. That's slightly more than a 40% reduction.

TrainedMonkey 12y ago

"the dual motor Model S will quickly torque sleep a drive unit when torque is not needed and instantly wake it up as the accelerator is pressed to command more torque." I can't understand this, is first torque meant to be toggle?

sp332 12y ago
"Torque sleep" just means the unit stops producing torque for a while.
dmckeon 12y ago
Torque sleep sounds like the electric motor equivalent of free-wheeling: https://en.wikipedia.org/wiki/Freewheel https://en.wikipedia.org/wiki/Freewheel
TD-Linux 12y ago
Tesla cars use induction motors. The rotors of an induction motor don't supply their own field, but need to be excited by current in the stator, which requires power. In addition, once there is a field, it produces hysteresis losses proportional to the speed of the motor. If the motor is completely off, the losses from freewheeling are very small. Cars based on permanent magnet motors do not need to use power to maintain the rotor's magnetic field. On the downside, the field cannot be shut off, so they always have hysteresis loss and cannot freewheel as nicely as induction motors can.

deleted 12y ago

[deleted]

portman 12y ago

The most under-reported aspect of driving a Tesla is how severely topography impacts range. Under normal conditions, I use 350 Wh/mi (watt-hours per mile). This is 17% more than "rated range" because -- and this is a technical term -- I drive like a madman. However, when driving to Tahoe (7000 feet higher), I end up using 850 Wh/mi: over 2x higher electricity consumption, because mountains. All this talk of tires and wind resistance is a red herring for topography, which does more to limit/extend range than any other factor. What's more, this could be so easily addressed with software: when I input my destination into GPS, the car should tell me my expected range. It knows the topography. Use the force, car! Taken one step further, since Tesla is constantly transmitting telemetry to home base, Tesla HQ likely knows the average battery consumption of all other drivers who have ever driven that route. This would allow non-topographical variables (traffic lights, potholes, road conditions) to be factored into the range calculation as well. Edit: Mistakenly used kWh/mi instead of Wh/mi units. Hat tip to Tarrosion for the correction.

hamburglar 12y ago
I've noticed this, too. I have a plug-in prius, which only gives you about a 10 mile electric range, so the game ends up being "can I make this trip to X and back without having to burn any gas?" Knowing the terrain in your neighborhoods and knowing the paths that don't involve a lot of elevation change can really make a big difference in whether you "win" this challenge.
greglindahl 12y ago
All cars use more energy to climb hills. If you'd like to factor that into your Tesla planning, check out https://evtripplanner.com/ https://evtripplanner.com/ -- It shows the Vacaville/Truckee segment as taking 173 rated miles to cover 130 actual miles.
- rconti 12y ago
  It's worth noting also that he's not talking about "driving in hilly terrain", the original comment is talking about driving almost exclusively uphill. Going to Tahoe you'd go from somewhere around 0ft to around 8500ft depending on the pass, and then down only to 6200ft. Of course, this will impact all cars, though I find only a few MPG difference in our vehicles driving up to the ski resorts around Tahoe. One curious thing I've noticed is that my relatively-high-Torque-and-HP car with a manual transmission gets almost the same mileage on flat ground versus going up and down mountain ranges, assuming there's no net elevation gain. My girlfriend's fairly underpowered Subaru with a 4 speed automatic does significantly worse in the hills than it does on flat ground. Also interestingly, the Tesla should get significantly better mileage in thinner air (on flat ground) where a gas-engined car has to deal with less air to burn which balances out the lower wind resistance. Would also be interesting to see how the elevation change would affect a tesla at net 0. Say, drive from Sacramento to Truckee and back; I think the range should be plenty.

MrFoof 12y ago

Quick note: These ranges probably assume a 100% charge. Although this should be obvious, it should be noted that the Model S does not charge to 100% by default. By default it charges to 80%. This can be overridden by the user (in preparation for long trips), though after a few days it reverts back to the 80%. This is the improve the overall durability of the battery -- that is, the maximum capacity remains higher for longer if the battery is not fully charged every cycle.