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Which numbers should I believe?

maverick3n1

Member
Apr 30, 2019
44
27
Oceanside
I've had my Tesla Model 3 Performance for exactly 1 week now, and have driven round trip to my office a minimum of 6 times now (or 12 travel attempts at 22 miles per travel attempt). In doing so, I've used it to test various travel distance numbers, and tried adapting driving habits to change those numbers.

My office is 22 miles from my house. One direction has a little bit more downhill than the other direction, but outside of a single steep hill that I go up and down (about a 25% grade at 25mph up and down, 300' each direction or so), most of it is only about a 5% grade one way or the other.

I've found that two of my single direction trips were 11% battery usage (one of which, I had the AC on. All other trips, it was off), and a single one way trip was 9% (I believe it was right on the edge of turning into 10%). All other trips were consistently 10% battery usage each way. By that math, the vehicle has a total range of 220 miles on a 100% to 0% charge, or 22 miles per 10%. I've tried driving aggressive, and I've also tried driving like a grandma, constantly watching my acceleration, trying not to peak over 20% of the black bar underneath the speedometer, and when going downhill, trying to maintain my speed while running in the green. Neither one has made a difference on this trip.

If I change my battery percentage to miles to empty however, it consistently reads that I get 30 miles per 10%, or 300 miles should I be charged to 100%. Today I was down to 30% (I haven't yet gotten my 220 outlet installed, so have been stuck charging at 110 and it's just not cutting it), and it stated I had 90 miles left when I switched to mile range rather than battery percentage. I know that in truth, if I'm lucky, I can go 66 miles in 30% battery, not 90. That's a pretty substantial difference!

So the first question is: Is the conversion from battery percentage to expected miles to dead battery, based on actual average driving, or is it based on the best possible outcome, and completely ignores your driving style?

Second, have you found that autopilot uses more power than manual drive, the same, or less? From what I've visibly experienced, it brakes and accelerates a lot more frequent than manual drive, which leads me to believe that it's not as efficient as manual driving.

Third, for those of you who have a Performance Model 3, what should I actually expect to get out of the vehicle in terms of range? Do you find you get better mileage on city streets or freeways? If you hold a consistent speed on the freeways, does it make much of a difference to stop and go on city streets? Also, have you noticed, is traveling at 80mph instead of 65 mph more or less efficient? I know there is a tipping point with ICE vehicles where the gear ratio combined with drag of the vehicle causes the vehicle to kill more gas than if you traveled slower for a longer period of time. Where have you found that sweet spot lays with Tesla?

Lastly, do you find that fast acceleration and then maintaining a higher speed is more battery efficient than slowly accelerating up to speed (lets say 65mph for reference), and then maintaining speed is more efficient? In the fast acceleration, technically, you'd only need to burst draw power for 4 seconds or so to be at 65mph, then drop off the accelerator and cruise. Is that not more efficient than drawing on the battery harder for 20 seconds to slowly get up to 65, but not peak it out?

Would love some insight!
 
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pdp1

Member
Oct 28, 2018
126
71
Northern California
I've had my Tesla Model 3 Performance for exactly 1 week now, and have driven round trip to my office a minimum of 6 times now (or 12 travel attempts at 22 miles per travel attempt). In doing so, I've used it to test various travel distance numbers, and tried adapting driving habits to change those numbers.

My office is 22 miles from my house. One direction has a little bit more downhill than the other direction, but outside of a single steep hill that I go up and down (about a 25% grade at 25mph up and down, 300' each direction or so), most of it is only about a 5% grade one way or the other.

I've found that two of my single direction trips were 11% battery usage (one of which, I had the AC on. All other trips, it was off), and a single one way trip was 9% (I believe it was right on the edge of turning into 10%). All other trips were consistently 10% battery usage each way. By that math, the vehicle has a total range of 220 miles on a 100% to 0% charge, or 22 miles per 10%. I've tried driving aggressive, and I've also tried driving like a grandma, constantly watching my acceleration, trying not to peak over 20% of the black bar underneath the speedometer, and when going downhill, trying to maintain my speed while running in the green. Neither one has made a difference on this trip.

If I change my battery percentage to miles to empty however, it consistently reads that I get 30 miles per 10%, or 300 miles should I be charged to 100%. Today I was down to 30% (I haven't yet gotten my 220 outlet installed, so have been stuck charging at 110 and it's just not cutting it), and it stated I had 90 miles left when I switched to mile range rather than battery percentage. I know that in truth, if I'm lucky, I can go 66 miles in 30% battery, not 90. That's a pretty substantial difference!

So the first question is: Is the conversion from battery percentage to expected miles to dead battery, based on actual average driving, or is it based on the best possible outcome, and completely ignores your driving style?

Second, have you found that autopilot uses more power than manual drive, the same, or less? From what I've visibly experienced, it brakes and accelerates a lot more frequent than manual drive, which leads me to believe that it's not as efficient as manual driving.

Third, for those of you who have a Performance Model 3, what should I actually expect to get out of the vehicle in terms of range? Do you find you get better mileage on city streets or freeways? If you hold a consistent speed on the freeways, does it make much of a difference to stop and go on city streets? Also, have you noticed, is traveling at 80mph instead of 65 mph more or less efficient? I know there is a tipping point with ICE vehicles where the gear ratio combined with drag of the vehicle causes the vehicle to kill more gas than if you traveled slower for a longer period of time. Where have you found that sweet spot lays with Tesla?

Lastly, do you find that fast acceleration and then maintaining a higher speed is more battery efficient than slowly accelerating up to speed (lets say 65mph for reference), and then maintaining speed is more efficient? In the fast acceleration, technically, you'd only need to burst draw power for 4 seconds or so to be at 65mph, then drop off the accelerator and cruise. Is that not more efficient than drawing on the battery harder for 20 seconds to slowly get up to 65, but not peak it out?

Would love some insight!
To address the 80 mph vs 65 mph question, just like an ICE, there is a tipping point, but for the Model 3 (or EVs in general) it’s really low, I read something like ~25 mph (https://electrek.co/2018/05/27/tesla-model-3-range-new-hypermiling-record/). So basically the faster average speed you go above ~25, the less efficient you’ll be. There are plenty of other factors like road conditions, temperature, and how often you’re braking (regenerative or otherwise), but generally speaking, slower the better for mileage.

Also like ICE, accelerating fast is generally less efficient than accelerating slowly. But of course, there is a low limit to how slow you accelerate before it starts becoming less efficient, but that’s gotta be pretty slow.
 
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darth_vad3r

Well-Known Sith
May 6, 2019
1,574
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Canada
The “% used in a trip” metric is the least accurate one you can use to compare trips.
9.4% can show as “9”, and 9.5% as “10”. Your “11” could have been 10.5, or 11.49.

If you want to compare more accurately, use a trip meter, and see what the car said the average Wh/mi was for the trip. Multiply that by miles and you get a number like 7,320 W used for one trip vs 7,050 W for another.

Don’t use the ‘kWh’ display from the trip on its own, that would just say “7” in both these cases.

I wrote a lost about this recently: https://teslamotorsclub.com/tmc/threads/method-to-calculate-extrapolate-battery-capacity-from-trip-consumption.152847/

Also, outdoor temperature has a significant impact on the battery efficiency, even if you use zero climate control.
Speed does as well. So does harder acceleration and braking vs smooth acceleration and maintaining constant speeds.

Enjoy the car *and* keep on calculating if you like (I love both :))
 
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A2be

Member
May 19, 2019
33
29
Denver, Colorado, USA, Sol3
Hi. Good questions @maverick3n1 and a bunch of good data on your first week with a Model 3.

I've had my Model 3 just a month, and love the car, but will hold off sharing my experiences for another post. This is my first post here on the TMC forum.

Here I'll just make two physics-based points that should help you THINK a bit about the general problem. These are simply true at a level of first principles, exactly the level Elon Musk is reknown for thinking about in his entrepreneurial ventures at SpaceX and Tesla. This info will definitely apply to several of your questions.

First, air resistance losses ("aerodynamic drag") is proportional to the square of the velocity of the vehicle. Thus, it is inevitable that higher speed driving has higher air drag losses, and that number goes up exponentially with speed.
For example, 60 mph (drag 3600) loses 9 times more energy to drag than 20 mph (drag 400). 3600 divided by 400 = 9.
90 mph will give up 20x more energy to drag than will 20 mph.

Second, there are real and measurable losses due to electrical resistance (in each battery itself; i.e. between the two terminals to each cell) AND in ALL the various wiring that that current must pass through to drive the inverter and motor. Sadly for efficiency, the electrical resistance losses are also proportional to the square of the current flowing. Always! One cannot escape this reality of physics.
Thus, when accelerating at higher rate, and drawing say 600 amps in the main batt cable (resistance losses 360,000) you are losing 36 times as much energy to electrically-generated heat losses vs 100 amps (resistance losses 10,000). 360,000 divided by 10,000 is 36.

The battery pack being divided by Tesla into several separate and parallel strings does not change this reality. If, say, four batt strings would carry only 1/4 of the current, so the 600A total would be just 150A per batt string vs 25A per string at 100A total, the difference remains 36x. (22,500/625 = 36).

So, always, your car will be more efficient, more of that stored energy from the batt pack converted to useful mechanical energy to move the mass of the car and its load to where you want to go, when operated at lower current draw, and at lower velocity, as compared to higher current draw and higher velocity.
 

ShockOnT

⚡️⚡️⚡️⚡️⚡️
Jun 26, 2016
3,406
3,189
Sydney
I've had my Tesla Model 3 Performance for exactly 1 week now, and have driven round trip to my office a minimum of 6 times now (or 12 travel attempts at 22 miles per travel attempt). In doing so, I've used it to test various travel distance numbers, and tried adapting driving habits to change those numbers.

My office is 22 miles from my house. One direction has a little bit more downhill than the other direction, but outside of a single steep hill that I go up and down (about a 25% grade at 25mph up and down, 300' each direction or so), most of it is only about a 5% grade one way or the other.

I've found that two of my single direction trips were 11% battery usage (one of which, I had the AC on. All other trips, it was off), and a single one way trip was 9% (I believe it was right on the edge of turning into 10%). All other trips were consistently 10% battery usage each way. By that math, the vehicle has a total range of 220 miles on a 100% to 0% charge, or 22 miles per 10%. I've tried driving aggressive, and I've also tried driving like a grandma, constantly watching my acceleration, trying not to peak over 20% of the black bar underneath the speedometer, and when going downhill, trying to maintain my speed while running in the green. Neither one has made a difference on this trip.

If I change my battery percentage to miles to empty however, it consistently reads that I get 30 miles per 10%, or 300 miles should I be charged to 100%. Today I was down to 30% (I haven't yet gotten my 220 outlet installed, so have been stuck charging at 110 and it's just not cutting it), and it stated I had 90 miles left when I switched to mile range rather than battery percentage. I know that in truth, if I'm lucky, I can go 66 miles in 30% battery, not 90. That's a pretty substantial difference!

So the first question is: Is the conversion from battery percentage to expected miles to dead battery, based on actual average driving, or is it based on the best possible outcome, and completely ignores your driving style?

Second, have you found that autopilot uses more power than manual drive, the same, or less? From what I've visibly experienced, it brakes and accelerates a lot more frequent than manual drive, which leads me to believe that it's not as efficient as manual driving.

Third, for those of you who have a Performance Model 3, what should I actually expect to get out of the vehicle in terms of range? Do you find you get better mileage on city streets or freeways? If you hold a consistent speed on the freeways, does it make much of a difference to stop and go on city streets? Also, have you noticed, is traveling at 80mph instead of 65 mph more or less efficient? I know there is a tipping point with ICE vehicles where the gear ratio combined with drag of the vehicle causes the vehicle to kill more gas than if you traveled slower for a longer period of time. Where have you found that sweet spot lays with Tesla?

Lastly, do you find that fast acceleration and then maintaining a higher speed is more battery efficient than slowly accelerating up to speed (lets say 65mph for reference), and then maintaining speed is more efficient? In the fast acceleration, technically, you'd only need to burst draw power for 4 seconds or so to be at 65mph, then drop off the accelerator and cruise. Is that not more efficient than drawing on the battery harder for 20 seconds to slowly get up to 65, but not peak it out?

Would love some insight!
For a short drive you also have to warm up the battery, so 10 x 20 mile trips will use more power than 1 x 200 mile trip.
 

maverick3n1

Member
Apr 30, 2019
44
27
Oceanside
For a short drive you also have to warm up the battery, so 10 x 20 mile trips will use more power than 1 x 200 mile trip.

What is the ideal battery temp? I was under the impression that room temp was better operating temp for a battery than a few hundred degrees, so I'm surprised that you'd have to wait much for a battery to get up to proper operating temps.
 

darth_vad3r

Well-Known Sith
May 6, 2019
1,574
1,177
Canada
So, always, your car will be more efficient, more of that stored energy from the batt pack converted to useful mechanical energy to move the mass of the car and its load to where you want to go, when operated at lower current draw, and at lower velocity, as compared to higher current draw and higher velocity.

Great first post. One tiny issue. I’m not sure about that last “always” (wrt velocity). There is some peak efficiency speed like 25mph or 40km/h I believe. The exact number isn’t my point, but rather that if such a number exists, then operating at lower velocity than that will not increase efficiency but rather decrease it, right?

There are other factors over and above the two you noted.
 

darth_vad3r

Well-Known Sith
May 6, 2019
1,574
1,177
Canada
What is the ideal battery temp? I was under the impression that room temp was better operating temp for a battery than a few hundred degrees, so I'm surprised that you'd have to wait much for a battery to get up to proper operating temps.

It’s warmer than room temp, something like 30°-40°C -ish, IIRC?

Also “ideal” is a loaded word. Ideal efficiency won’t be ideal for battery life, so there is a compromise the BMS is making I believe. There was some data regarding this when the S had “range mode” people could see the battery temp be allowed to climb from say 30 to 40C to allow more range (presumably at the expense of some degradation).
 

A2be

Member
May 19, 2019
33
29
Denver, Colorado, USA, Sol3
Great first post. One tiny issue. I’m not sure about that last “always” (wrt velocity). There is some peak efficiency speed like 25mph or 40km/h I believe. The exact number isn’t my point, but rather that if such a number exists, then operating at lower velocity than that will not increase efficiency but rather decrease it, right?

There are other factors over and above the two you noted.

That is a great nuance, @darth_vad3r . There are definitely multiple factors at play, and not merely the two (velocity of the vehicle and electrical current in the various battery/pack/inverter/motor wiring, and there might be some strange optimizations as many of the factors combine together. Some could even be strange things known only be the engineers and software engineers who know how they've chosen to optimize many things, and of course, even those could change from software version to version.

However, the "always" statement does always apply to these two things when considered independently. When all other factors are held constant. And this outcome derives from basic physics, in both cases.

1) Aerodynamic drag is always higher at a higher velocity vs a lower velocity, and that drag is proportional to the square of the velocity. So it is geometrically higher at each higher speed. (of course, with the caveat, "all other things held constant")

2) Electrical resistance losses (what engineers call "I-squared R" losses) are always higher at higher current vs lower current, and those resistive losses are proportional to the square of the current flowing in the various battery/cabling/inverter/&motor circuits. (of course, with the caveat, "all other things held constant")

But as real things mix, and people are often not driving at a fixed speed on level ground, of course many other things can also come into play (environmental heating or cooling; batt pack heating or cooling; accessory power use, ...).

I can see how some velocity greater than a near zero-velocity (say 1 or 2 mph) is likely optimum, and that optimum velocity is likely at or below 25 mph, since by that time, the aerodynamic drag begins to predominate by 40 km/hr or 25 mph. It might be interesting sometime to have a post on that topic alone. The challenge would be to get hard data on what Tesla is doing with all the many other variables that also use energy, as a function of vehicle velocity, and of the traction power circuit currents. But that stuff is all proprietary in their source code that Tesla does not disclose publically.
 

darth_vad3r

Well-Known Sith
May 6, 2019
1,574
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Canada
For your consideration:
model_s3x_range_imperial.png.c3a595fdc0c5bc87870b8131c77ee68b.png

Source: Model 3 Consumption and Charging

Seems like optimal speed is 35-ish mph.

I think we are coming at “efficiency” differently. Most people would define “most efficient” as using the least amount of energy to arrive at their destination. This isn’t necessarily the same as the car using the least power. I think your comments are more correct for power, but not energy per trip distance which factors time as well.
 
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ShockOnT

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Jun 26, 2016
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What is the ideal battery temp? I was under the impression that room temp was better operating temp for a battery than a few hundred degrees, so I'm surprised that you'd have to wait much for a battery to get up to proper operating temps.
I think the ideal temp is around 30 or 40C. But either way, it will be a few degrees different to your garage even on a mild day.
 

maverick3n1

Member
Apr 30, 2019
44
27
Oceanside
So with the debate of efficiency levels based on speed.. the next/true question is... how did Tesla rate the range? If Tesla says XYZ vehicle has a range of 300 miles, I know, most vehicles report their mpg based on flat terrain at a fixed speed etc.. what speed is Tesla saying you will get 300miles on a full charge? Surely not 25 or 35mph!
 

TT97

Active Member
Aug 6, 2017
2,173
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Los Angeles
So with the debate of efficiency levels based on speed.. the next/true question is... how did Tesla rate the range? If Tesla says XYZ vehicle has a range of 300 miles, I know, most vehicles report their mpg based on flat terrain at a fixed speed etc.. what speed is Tesla saying you will get 300miles on a full charge? Surely not 25 or 35mph!

It's based on EPA test cycles (as are fuel economy testing for ICE vehicles - just slightly different methodology). Mostly done on Dyno. City assume stop & go traffic with idling times, 21 mph average, 56 mph max speed. Highway test cycle 60 mph max, 48 mph average, no idling. Very slow acceleration for both (about 18 seconds 0-60)
 

A2be

Member
May 19, 2019
33
29
Denver, Colorado, USA, Sol3
For your consideration:
model_s3x_range_imperial.png.c3a595fdc0c5bc87870b8131c77ee68b.png

Source: Model 3 Consumption and Charging

Seems like optimal speed is 35-ish mph.

I think we are coming at “efficiency” differently. Most people would define “most efficient” as using the least amount of energy to arrive at their destination. This isn’t necessarily the same as the car using the least power. I think your comments are more correct for power, but not energy per trip distance which factors time as well.

That is very interesting empirical data that ABRP has collected from some decent sample of Teslas. But it is not looking merely at the efficiency of the car moving at various speeds (something the driver can control) or how rapidly or how chill the driver chooses to accelerate the vehicle.

It includes ALL energy use, including heat or air conditioning, warming or cooling of the batt pack, lights and other electrical loads, etc.
Since all of those other energy use loads contribute nothing to mechanically moving the car, of course all of them reduce range, and will exhibit a very different shaped curve of Range vs Speed. They are all maximally inefficient at lower speed. (at idle, they would have be the most inefficient in terms of contributing to mechanical motion of the EV.

So, when those loads are shown with the electrical loads that make the car motivate, they can mislead the driver into thinking that 35 mph is the most efficient from a mechanical point of view. That the driver will drive farther at 35 mph rather than, say 20, 25, or 30 mph. That is simply not so. The data are skewed by the presence of all drivers in the large ABRP sample, most of whom are not aiming to take a range-maximizing trip today before their next charge, and therefore includes a lot of short trips, and medium trips, that have higher-than-average startup and other electrical loads.
 

F14Scott

Member
Apr 7, 2019
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381
Houston
That is very interesting empirical data that ABRP has collected from some decent sample of Teslas. But it is not looking merely at the efficiency of the car moving at various speeds (something the driver can control) or how rapidly or how chill the driver chooses to accelerate the vehicle.

It includes ALL energy use, including heat or air conditioning, warming or cooling of the batt pack, lights and other electrical loads, etc.
Since all of those other energy use loads contribute nothing to mechanically moving the car, of course all of them reduce range, and will exhibit a very different shaped curve of Range vs Speed. They are all maximally inefficient at lower speed. (at idle, they would have be the most inefficient in terms of contributing to mechanical motion of the EV.

So, when those loads are shown with the electrical loads that make the car motivate, they can mislead the driver into thinking that 35 mph is the most efficient from a mechanical point of view. That the driver will drive farther at 35 mph rather than, say 20, 25, or 30 mph. That is simply not so. The data are skewed by the presence of all drivers in the large ABRP sample, most of whom are not aiming to take a range-maximizing trip today before their next charge, and therefore includes a lot of short trips, and medium trips, that have higher-than-average startup and other electrical loads.
Your point reminds me of our BINGO profiles in the jet, whereby one flies a climb, cruise, and descent specifically designed to maximize range (when one is BINGO, i.e. emergency fuel state). When one BINGOs into a headwind, slowing down would seem prudent, but the opposite, while counterintuitive, is true. The reason one flies faster into a headwind is so that one spends less time in the air while getting to the destination; time aloft is not the goal.

Similarly, I would guess that the greater the "hotel load" (to use a cruise ship term for power needed not for propulsion), the faster the ship must sail for Rmax, all the while balancing that necessity with the square of the drag. Same in the Tesla.
 

Daniel in SD

Well-Known Member
Jan 25, 2018
7,043
10,458
San Diego
2) Electrical resistance losses (what engineers call "I-squared R" losses) are always higher at higher current vs lower current, and those resistive losses are proportional to the square of the current flowing in the various battery/cabling/inverter/&motor circuits. (of course, with the caveat, "all other things held constant")
True of course but the motor can be more efficient at high torque and if you accelerate faster you arrive faster thereby reducing fixed loads (HVAC, computer, etc.).
Here’s the plot for a Nissan Leaf motor (I haven’t seen one for a Model 3). At higher RPM it’s most efficient with the pedal to the metal. Seems like a very complicated optimization problem! Tesla should add a hypermiler launch control mode that accelerates you to the optimal speed in the most optimal way.
A8C634D3-8DB4-4F33-9E07-1572A3BDD551.png
 
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Magnets!

Member
Jan 9, 2019
661
301
California
What speed are you running on the highway? what percent is city streets vs. highway? Hilly terrain definitely draws more power. The downs don't make up for the climbs. Are you leaving sentry mode on all day at work? That's about 8 miles of range lost...did you exclude that from the math?

My M3P seems to average about 275 wh/mile in average driving (23 mile trip) with a mix of highway/city. (air temps of 65-75 and AC set at 73). This includes a bit of fun driving but cruise set at 74 on the highway. At 275 wh/mile my range is about 272 miles. I also run my tires at 40psi which costs me some efficiency but improved ride quality. By the way, I didn't get this level of efficiency when my car was new either.
 

AlanSubie4Life

Efficiency Obsessed Member
Oct 22, 2018
10,810
13,509
San Diego
I've had my Tesla Model 3 Performance for exactly 1 week now, and have driven round trip to my office a minimum of 6 times now (or 12 travel attempts at 22 miles per travel attempt). In doing so, I've used it to test various travel distance numbers, and tried adapting driving habits to change those numbers.

My office is 22 miles from my house. One direction has a little bit more downhill than the other direction, but outside of a single steep hill that I go up and down (about a 25% grade at 25mph up and down, 300' each direction or so), most of it is only about a 5% grade one way or the other.

I've found that two of my single direction trips were 11% battery usage (one of which, I had the AC on. All other trips, it was off), and a single one way trip was 9% (I believe it was right on the edge of turning into 10%). All other trips were consistently 10% battery usage each way. By that math, the vehicle has a total range of 220 miles on a 100% to 0% charge, or 22 miles per 10%. I've tried driving aggressive, and I've also tried driving like a grandma, constantly watching my acceleration, trying not to peak over 20% of the black bar underneath the speedometer, and when going downhill, trying to maintain my speed while running in the green. Neither one has made a difference on this trip.

If I change my battery percentage to miles to empty however, it consistently reads that I get 30 miles per 10%, or 300 miles should I be charged to 100%. Today I was down to 30% (I haven't yet gotten my 220 outlet installed, so have been stuck charging at 110 and it's just not cutting it), and it stated I had 90 miles left when I switched to mile range rather than battery percentage. I know that in truth, if I'm lucky, I can go 66 miles in 30% battery, not 90. That's a pretty substantial difference!

So the first question is: Is the conversion from battery percentage to expected miles to dead battery, based on actual average driving, or is it based on the best possible outcome, and completely ignores your driving style?

Second, have you found that autopilot uses more power than manual drive, the same, or less? From what I've visibly experienced, it brakes and accelerates a lot more frequent than manual drive, which leads me to believe that it's not as efficient as manual driving.

Third, for those of you who have a Performance Model 3, what should I actually expect to get out of the vehicle in terms of range? Do you find you get better mileage on city streets or freeways? If you hold a consistent speed on the freeways, does it make much of a difference to stop and go on city streets? Also, have you noticed, is traveling at 80mph instead of 65 mph more or less efficient? I know there is a tipping point with ICE vehicles where the gear ratio combined with drag of the vehicle causes the vehicle to kill more gas than if you traveled slower for a longer period of time. Where have you found that sweet spot lays with Tesla?

Lastly, do you find that fast acceleration and then maintaining a higher speed is more battery efficient than slowly accelerating up to speed (lets say 65mph for reference), and then maintaining speed is more efficient? In the fast acceleration, technically, you'd only need to burst draw power for 4 seconds or so to be at 65mph, then drop off the accelerator and cruise. Is that not more efficient than drawing on the battery harder for 20 seconds to slowly get up to 65, but not peak it out?

Would love some insight!

I have been trying to answer this question. The reason you don’t get the rated range is because of the tires (the EPA test was conducted with the AWD which has different tires, this is allowed).

For range, the rate you accelerate is largely irrelevant, because for a long unimpeded road trip on freeway, you accelerate exactly once (or at most, just a handful of times). This situation is where range is usually relevant. So would not worry about acceleration too much. For day-to-day stop-and-go it matters, has been discussed above.

I think you are probably never going to get more than about 280 miles with the PS4S at reasonable freeway speeds. Should be able to get over 300 with MXM4 replacements (don’t recommend it).

My data gathering is still a work in progress, it’s in the thread “Performance not getting 310 miles promised”. (Note: 310 miles was NOT promised with Performance - I did not pick the provocative title)

Latest trip, driven extremely efficiently, but not representative of a wide open freeway drive, I got 268Wh/mi. No HVAC. This implies a range of 270miles. (Reality is you can take it 4-6 miles past zero and you might squeeze out 275 miles - not recommended.)

(For comparison, my brother in a P3D Stealth with MXM4s had no problem getting 247Wh/mi with most driving done at 70-77mph). This is about 10% better than what I would likely do with PS4S on an identical trip.

Also, I’ve found that for every ~232Wh the trip meter says you use, you lose 1 rated mile. For a long enough drive you can verify that yourself by checking rated miles before and after and logging the trip meter details. There is nothing that guarantees the trip meter is accurate in an absolute sense - it is just a guide for efficiency relative to your previous efforts. To me it seems to read energy usage about 3-4% low (distance seems to be correct).

For multiday discharges your “range” will be lower due to vampire losses. I put range in quotes because in this context range does not matter, because you just charge every night in most cases. Vampire is really just a negative for operating cost. Not really a factor for range (in most cases - there are exceptions of course - like multi-day backpacking, leaving car at airport, etc.).
 
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AlanSubie4Life

Efficiency Obsessed Member
Oct 22, 2018
10,810
13,509
San Diego
Is the conversion from battery percentage to expected miles to dead battery, based on actual average driving, or is it based on the best possible outcome, and completely ignores your driving style?

It is fixed. It does NOT depend on your driving. These are referred to as “rated miles” (rmi)

It is neither the best possible outcome or the worst. The miles simply indicate energy. From what I have seen each mile represents 232Wh/rmi in the P3D+ (probably the same for all AWD vehicles). See above for discussion of details of where this number comes from. However, a 75kWh battery would imply 242Wh/mi. Would not worry about the conflicting info too much...think it is a function of choices Tesla decides to make to present to the driver.

In reality you can go about 6 rated miles past zero (see Elon’s tweet), but it is not at all recommended.

or 300 miles should I be charged to 100%

A full charge should give you 310 miles or so with the AWD version of the vehicle. You may have to charge fully to balance to battery to get this. No need though.
 

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