A senior tesla executive's comforting answer to concerns re: "loss of range"

[djp]

I doubt they've changed the "buffer" below zero. I think it's more likely that the inaccurate estimates meant the rated miles would roll off at an inconsistent rate as the SOC dropped.

We know the mid-level estimate was a WAG. The estimate gets more accurate at lower SOC since the voltage cut-off is a fixed point. At mid-level the algorithm probably ticked down the rated miles at a constant rate, but then would realize it was getting ahead of itself as the estimate became more accurate, and respond by slowing down the rate that rated miles rolled off the display.

I think the zero point is still where it always was, but the rated Wh/m should be more consistent now.

 

[Lou in SoCal]

If you click on the battery icon, it gives markers for every 10th percentile of charge. It's easy enough to determine the percentage that way.

 

[Cal1]

It's next to impossible to get absolute numbers from a battery. Gasoline and Diesel are both liquids, so there is no guessing. Having said that, having a percentage readout in addition to the battery bar and rated range would be a big help. Tesla software engineers of all people should know this, as their coast to coast trip cars have this ability. If it didn't help in range estimation, they would just run stock firmware.

Not sure I understand why measurement is so hard. We measure everything else. In line ammeters are common and pretty straight forward in current measurement. Voltmeters can easily measure voltage levels. I don't see why a basic software app couldn't give us something. Not trying to be augmentative, just don't see the problem. And it would satisfy a portion of owners wanting something other than changing range guesses. Given Tesla's repeated assurance that nothing is really changing, they must have something they are basing this on. Exactly what are they basing these claims on?

 

[Kraken]

I doubt they've changed the "buffer" below zero. I think it's more likely that the inaccurate estimates meant the rated miles would roll off at an inconsistent rate as the SOC dropped.

We know the mid-level estimate was a WAG. The estimate gets more accurate at lower SOC since the voltage cut-off is a fixed point. At mid-level the algorithm probably ticked down the rated miles at a constant rate, but then would realize it was getting ahead of itself as the estimate became more accurate, and respond by slowing down the rate that rated miles rolled off the display.

I think the zero point is still where it always was, but the rated Wh/m should be more consistent now.

it's clear that they did some changing of the buffer below zero. Look at my pictures in the other thread. 5 miles left clearly has far less battery left than 7 miles did previously according to the pictures

 

[djp]

it's clear that they did some changing of the buffer below zero. Look at my pictures in the other thread. 5 miles left clearly has far less battery left than 7 miles did previously according to the pictures

It could just be the graphic that's changed, but no difference to the actual SOC at zero miles.

 

[djp]

Not sure I understand why measurement is so hard.

Advanced ICs Simplify Accurate State-of-Charge Measurement for Lithium-Ion Batteries

 

[aronth5]

IMO this range estimate thing *IS* necessary on EVs until sufficient infrastructure (read: superchargers) exist such that I don't have to plan. That's why "1/4 tank of gas" works -- because as I get lower, I can just stop anywhere and fill up. Not so with an EV. Yet.

Agree.

 

[Doug_G]

I can't fathom everyone who report numbers under 300. In winter I'm at 450, and in summer I'm averaging 375.

Odd. In summer I can get rated consumption at 90-95 kph (56-59 mph) in reasonably good conditions.

 

[Cal1]

Advanced ICs Simplify Accurate State-of-Charge Measurement for Lithium-Ion Batteries

Thank you so much for this link!

 

[aviators99]

I don't buy this answer (for my car, anyway). I've been comparing rated miles on different vehicles running the same firmware, and have noticed material differences between "A" and "B" packs. So yobigd20, you can feel satisfied that I have always given you just as much credence as a Tesla Exec.

 

[MikeC]

I doubt they've changed the "buffer" below zero. I think it's more likely that the inaccurate estimates meant the rated miles would roll off at an inconsistent rate as the SOC dropped.

I think if the miles "are really there" then it could be that the amount of energy to go 1 rated mile varies by car but is consistent throughout the SoC for a given car (due to the algorithm). This might explain why people have a different value for Wh/mi when projected and rated miles match (per cinergi's thread).

 

[stevezzzz]

All this discussion brings up a real puzzler: why is it easy for some people to get Wh/mi consumption below 300, and for others it is impossible? I just drove about 80 mostly highway miles this evening at 296 Wh/mi; and I wasn't even trying, with speeds of 65-80 over much of the distance. My lifetime average through two winters and a summer is 313 Wh/mi.

Here's what I think I know about what makes these numbers possible:

- 19" wheels, S85
- 5000'+ elevation (lower air density means less aero drag)
- reasonably level terrain except when I drive up into the mountains.
- moderate climate; low average wind speed.

BTW, my Rated miles remaining equals Projected Average miles remaining when the average consumption reads 302-303 Wh/mi. Some others have reported that they have to get consumption down into the 280's before this is true for them.

 

[Kraken]

All this discussion brings up a real puzzler: why is it easy for some people to get Wh/mi consumption below 300, and for others it is impossible? I just drove about 80 mostly highway miles this evening at 296 Wh/mi; and I wasn't even trying, with speeds of 65-80 over much of the distance. My lifetime average through two winters and a summer is 313 Wh/mi.

Here's what I think I know about what makes these numbers possible:

- 19" wheels, S85
- 5000'+ elevation (lower air density means less aero drag)
- reasonably level terrain except when I drive up into the mountains.
- moderate climate; low average wind speed.

BTW, my Rated miles remaining equals Projected Average miles remaining when the average consumption reads 302-303 Wh/mi. Some others have reported that they have to get consumption down into the 280's before this is true for them.

Proper tire inflation, air suspension or not, battery pack type, firmware, bad alignment, etc.


for all we know the main culprit here is that some peoples tires aren't properly inflated. Their car is using more energy per mile and the algorithm is thus getting confused.

 

[Chipper]

+1

This has annoyed me since i bought the car back in 2012. Based on the early info I believed that I would actually be able to get 300 miles under ideal conditions at 55MPH and 265 miles at 65MPH, however I have never been able to get those numbers, even under perfect conditions. Even driving 55, there is no way I'd get 300 miles out of the car.

Love my Tesla, but I'm still upset about this.

When I had owned my S for only 3 weeks I drove it from my house to Vanderbilt Medical Center in Nashville (148.2 miles) and back home on a single charge. I arrived home with 4 miles rated range showing. I drove 65 MPH going over to Nashville and a little less on the way back.

 

[djp]

I think if the miles "are really there" then it could be that the amount of energy to go 1 rated mile varies by car but is consistent throughout the SoC for a given car (due to the algorithm). This might explain why people have a different value for Wh/mi when projected and rated miles match (per cinergi's thread).

Yes, if the algorithm underestimated range then you could match rated range at a higher Wh/m (ie. miles would come off more slowly), which could explain the differences that people were seeing on cingeri's thread. I wouldn't assume it's linear though, I'd expect a curve as the estimate gets better at lower SOC.

The "Wh/m to match rated" should be the same for all cars (given consistent tire inflation, temperature, altitude, alignment, etc). It'll be interesting to see if the new algorithm brings everyone's rated Wh/m numbers closer together.

 

[RDoc]

All this discussion brings up a real puzzler: why is it easy for some people to get Wh/mi consumption below 300, and for others it is impossible? I just drove about 80 mostly highway miles this evening at 296 Wh/mi; and I wasn't even trying, with speeds of 65-80 over much of the distance. My lifetime average through two winters and a summer is 313 Wh/mi.

Here's what I think I know about what makes these numbers possible:

- 19" wheels, S85
- 5000'+ elevation (lower air density means less aero drag)
- reasonably level terrain except when I drive up into the mountains.
- moderate climate; low average wind speed.

BTW, my Rated miles remaining equals Projected Average miles remaining when the average consumption reads 302-303 Wh/mi. Some others have reported that they have to get consumption down into the 280's before this is true for them.

Do you generally have the wind behind you?

 

[scaesare]

All this discussion brings up a real puzzler: why is it easy for some people to get Wh/mi consumption below 300, and for others it is impossible? I just drove about 80 mostly highway miles this evening at 296 Wh/mi; and I wasn't even trying, with speeds of 65-80 over much of the distance. My lifetime average through two winters and a summer is 313 Wh/mi.

Here's what I think I know about what makes these numbers possible:

- 19" wheels, S85
- 5000'+ elevation (lower air density means less aero drag)
- reasonably level terrain except when I drive up into the mountains.
- moderate climate; low average wind speed.

BTW, my Rated miles remaining equals Projected Average miles remaining when the average consumption reads 302-303 Wh/mi. Some others have reported that they have to get consumption down into the 280's before this is true for them.

I suspect some of what you mention are indeed factors. I recently had a P85 loaner... while I initially had some fun "evaluating it's increased performance envelope", my following couple of commute cycles didn't allow me to drive any different than I did normally. For the same temps on identical routes ant identical speeds, the power consumption was probably 10-20% higher.

I noticed because I was getting high 300's for a consumption rate in my Standard... the perf was in the low 400's.

21" Tires?

 

[WarpedOne]

This "range estimation drama" steems from simply "too precise" prediction. Estimation simply cannot give the correct answer.
What ICE car predicts the range in one mile increments? Any when you drive it, you actual range differs every single time.
What added value is there in such precise number? Tesla shoudl simply display SOC in % and maybe give an estimation of range in 5% of max range steps.
Anything above 95% should read 270 miles and then decrease in ~5% steps but alwous rounded to nearest 10mile multiple (ie. 260, 250, 240, 230, ...).

People would not obsess about 1 mile drop in max range nor would they count on those 5 mile range left being enough for their 3 mile trip to next charger.

 

[dave]

All this discussion brings up a real puzzler: why is it easy for some people to get Wh/mi consumption below 300, and for others it is impossible? I just drove about 80 mostly highway miles this evening at 296 Wh/mi; and I wasn't even trying, with speeds of 65-80 over much of the distance. My lifetime average through two winters and a summer is 313 Wh/mi.

Here's what I think I know about what makes these numbers possible:

- 19" wheels, S85
- 5000'+ elevation (lower air density means less aero drag)
- reasonably level terrain except when I drive up into the mountains.
- moderate climate; low average wind speed.

BTW, my Rated miles remaining equals Projected Average miles remaining when the average consumption reads 302-303 Wh/mi. Some others have reported that they have to get consumption down into the 280's before this is true for them.

Since all the firmware updates, algorithm / balancing debates, I've been less concerned about what the rated range number is, and more concerned about exactly this - how many miles I'm actually getting on a charge and the average Wh/mi.

I would also like to know why I can't get the rated range as easily as other people here. I'm going to ask Tesla to take a look at it next time I'm in, because something is just not right. I do have the P85, and I do have a spoiler installed. I wonder if either or both of those things come into play? We do have rolling hills here, but they are quite mild. Perhaps I'm underestimating how bad they're affecting my range?

My tires are inflated properly, and I'm currently on the stock 19's as well.

 

[rlang59]

This "range estimation drama" steems from simply "too precise" prediction. Estimation simply cannot give the correct answer.
What ICE car predicts the range in one mile increments? Any when you drive it, you actual range differs every single time.
What added value is there in such precise number? Tesla shoudl simply display SOC in % and maybe give an estimation of range in 5% of max range steps.
Anything above 95% should read 270 miles and then decrease in ~5% steps but alwous rounded to nearest 10mile multiple (ie. 260, 250, 240, 230, ...).

People would not obsess about 1 mile drop in max range nor would they count on those 5 mile range left being enough for their 3 mile trip to next charger.

My wife's CRV.