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

[teslasguy]

What a great response from Jerome. Now this is the Tesla many of us love and find so refreshingly unlike the traditional dealership models! I have openly accused Jerome on these forums of responding with "blow off", traditional car company jargon without seeming to give any real credence to the issues I've submitted. But I believe in also being just as open with praise when deserved. Jerome obviously listened, took the issue seriously and had a credible investigation done. And then finally delivered a great response. Now I'm ready to go "sell" another 10 Teslas!!

 

[Alfred]

I submit that Tesla should calibrate and monitor the battery capacity in absolute energy units.
This business of introducing a rated range between owners and the real capacity of the battery just introduces confusion and uncertainty regarding the time evolution of battery capacity. I suppose it does provide Tesla with some wiggle room, but I'm not sure I want them to have that. I'd prefer that we mutually agree on what the best interpretation of battery state is at any given time, without questions about software that implements a range calculation.
FWIW...

This would be less practical. You want to know how far you can go. The Roadster shows two ranges: One based on how you drove (and heated), taking an average over your last 60 km or so and another based on a standard, very economical way of driving. Experience teaches you what you can expect between those two, based on your knowledge of the driving conditions ahead of you. A step ahead could be integration with your navigation system, including a link to meteorological data. Head winds e.g. can make a much larger difference to any estimate than small, mostly single digit variations of battery capacity estimates.

 

[qwk]

It's going to be very interesting comparing all of the year+ old cars rated range on this new more accurate firmware, to brand new cars. Maybe this new update will finally tell us how well the battery is faring? Up to this point all of the algorithm changes have done nothing but create panic and speculation.

 

[dennis]

What a great response from Jerome. Now this is the Tesla many of us love and find so refreshingly unlike the traditional dealership models! I have openly accused Jerome on these forums of responding with "blow off", traditional car company jargon without seeming to give any real credence to the issues I've submitted. But I believe in also being just as open with praise when deserved. Jerome obviously listened, took the issue seriously and had a credible investigation done. And then finally delivered a great response. Now I'm ready to go "sell" another 10 Teslas!!

+1.

 

[Cal1]

Originally Posted by ThosEM
I submit that Tesla should calibrate and monitor the battery capacity in absolute energy units.
This business of introducing a rated range between owners and the real capacity of the battery just introduces confusion and uncertainty regarding the time evolution of battery capacity. I suppose it does provide Tesla with some wiggle room, but I'm not sure I want them to have that. I'd prefer that we mutually agree on what the best interpretation of battery state is at any given time, without questions about software that implements a range calculation.

FWIW...

This would be less practical. You want to know how far you can go. The Roadster shows two ranges: One based on how you drove (and heated), taking an average over your last 60 km or so and another based on a standard, very economical way of driving. Experience teaches you what you can expect between those two, based on your knowledge of the driving conditions ahead of you. A step ahead could be integration with your navigation system, including a link to meteorological data. Head winds e.g. can make a much larger difference to any estimate than small, mostly single digit variations of battery capacity estimates.

I disagree and feel this is a self inflicted wound. Conventional displays have us conditioned to look for absolute energy levels. EVERYONE knows what a 1/4 tank means, and no one expects anybody to tell them how far they will go. Gee, they actually figure out (on their own) that a 1/4 tank means drastically different things on a truck, sports car etc. Just give me a display with an absolute amount of current left, somewhere! I'll figure out how to use it. Kind of like understanding that if I have a 1/4 tank of gas left, I might want to refuel sometime soon. This codependent attitude of assuming they have to give us accurate estimations of how far we are going on a tank is insane. Of course 5 gallons will go a lot further if I'm driving on a flat road with no head wind. I can't realistically expect an onboard computer to calculate anything but a SWAG.

But if I knew from day 1 that my battery started out storing X number of KW on a 90% charge and now after 14kmiles it only stores Y on the same charge... well I think I've got something to really work with. If I left the house with X number of KW and my display only shows Y ... I think most folks will quickly figure out when they need to refuel and start thinking about how far they can go on a full, half or quarter charge. I don't propose the abandon the current range display, just add something else and let us figure out how to use it.

UNLESS (dark conspiracy side rising) Tesla knows absolute watt storage varies or is falling and they don't want to open that can of worms. Of course this is a whole different Oprah show.

 

[qwk]

Originally Posted by ThosEM
I submit that Tesla should calibrate and monitor the battery capacity in absolute energy units.
This business of introducing a rated range between owners and the real capacity of the battery just introduces confusion and uncertainty regarding the time evolution of battery capacity. I suppose it does provide Tesla with some wiggle room, but I'm not sure I want them to have that. I'd prefer that we mutually agree on what the best interpretation of battery state is at any given time, without questions about software that implements a range calculation.

FWIW...

I disagree and feel this is a self inflicted wound. Conventional displays have us conditioned to look for absolute energy levels. EVERYONE knows what a 1/4 tank means, and no one expects anybody to tell them how far they will go. Gee, they actually figure out (on their own) that a 1/4 tank means drastically different things on a truck, sports car etc. Just give me a display with an absolute amount of current left, somewhere! I'll figure out how to use it. Kind of like understanding that if I have a 1/4 tank of gas left, I might want to refuel sometime soon. This codependent attitude of assuming they have to give us accurate estimations of how far we are going on a tank is insane. Of course 5 gallons will go a lot further if I'm driving on a flat road with no head wind. I can't realistically expect an onboard computer to calculate anything but a SWAG.

But if I knew from day 1 that my battery started out storing X number of KW on a 90% charge and now after 14kmiles it only stores Y on the same charge... well I think I've got something to really work with. If I left the house with X number of KW and my display only shows Y ... I think most folks will quickly figure out when they need to refuel and start thinking about how far they can go on a full, half or quarter charge. I don't propose the abandon the current range display, just add something else and let us figure out how to use it.

UNLESS (dark conspiracy side rising) Tesla knows absolute watt storage varies or is falling and they don't want to open that can of worms. Of course this is a whole different Oprah show.

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.

 

[Obsoletion]

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.

I agree and also note that on my ICE vehicles they have a miles to empty that works fairly well as it estimates this remaining range based on the current/short term average it is getting. But, it also has a fuel gauge. I would like a % of battery life gauge/read out and the estimate range remaining.

 

[Incredulocious]

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.

I was just about to say the same: it's very difficult to determine the charge state of a battery; it's not like measuring the contents of a liquid fuel tank. And this same discussion about wanting a percentage display (even if not super-accurate) has persisted in the Nissan LEAF community.

I find it fascinating how strongly people want a percentage display despite how all these vehicles do have a visual representation of remaining charge (similar to an ICE vehicle's fuel gauge) that allows you to roughly judge the remaining "fuel": 1/2, 1/3, 1/4, etc. I presume the manufacturers chose to do this over giving a more precise percentage number because of how difficult it is to estimate the remaining charge accurately. Nissan did relent though and added a percentage charge display to the 2013 LEAF.

It's interesting that even with 250-ish miles of range in the Model S, this concern over the range estimate and the wish for a more precise display persists, despite the similar lack of concern for such displays in our ICE vehicles.

Maybe folks will relax when we get to 500+ miles range....?!? But seriously, we'd be worrying about the last 10% much less often and be much less concerned about degradation with so much to spare.

 

[cinergi]

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.

 

[Doug_G]

I agree and also note that on my ICE vehicles they have a miles to empty that works fairly well as it estimates this remaining range based on the current/short term average it is getting. But, it also has a fuel gauge. I would like a % of battery life gauge/read out and the estimate range remaining.

Have you ever checked the "miles to empty" thing? Whenever I got a new ICE car I make a point of running the car down to empty, then fill the tank all the way to see how much gas it takes. I always found that those "distance remaining" displays are ridiculously conservative.

 

[Super Gizmo]

I don't think it's personal. I think people were looking for an answer from someone within Tesla who could speak from fact, rather than speculation (no matter how reasonable the speculation seemed).

Thank you, Bonnie for pointing this out. That is why I posted the response on both forums to put people's mind to rest because many have been worried about this issue - understandably.

 

[Odenator]

I am still confused by this statement: "The physical distance you can drive the vehicle from full to empty remains the same, only the displayed estimate has changed."

As I have posted on other threads, my battery on Nov '13 showed my rated range to be 231 miles on a 100% charge. After doing all that voodoo the SC told me to do to get back my miles, I am now back to 264 rated miles on a 100% charge.

Here is my question to all the smart people on the forum: Could I have driven 264 actual miles back on Nov '13 when my battery only displayed 231 rated miles if I drove conservatively so that my actual miles equaled my rated miles (about 300Wh/mile I think)? Please ignore the hidden reserve.

 

[Super Gizmo]

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.

+ 1

 

[qwk]

Here is my question to all the smart people on the forum: Could I have driven 264 actual miles back on Nov '13 when my battery only displayed 231 rated miles if I drove conservatively so that my actual miles equaled my rated miles (about 300Wh/mile I think)? Please ignore the hidden reserve.

I don't think that anyone can answer this. I would think no, but if what Jerome said is true(it was just a software estimation error), then it sure sounds like it. I wouldn't want to be the one taking a road trip which depends on that range.

 

[dave]

If I drive like a saint, observing the speed limit and carefully accelerating and so on, no matter what I do, I get over 300Wh/mi.
I don't think I've ever been able to get it below 300 for any length of time.

+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.

 

[liuping]

+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.

I have no problem staying under 300Wh/mile if I drive conservatively. I usually don't, but that is not the cars fault

Do you run with heat/or A/C?

 

[Mario Kadastik]

I am still confused by this statement: "The physical distance you can drive the vehicle from full to empty remains the same, only the displayed estimate has changed."

As I have posted on other threads, my battery on Nov '13 showed my rated range to be 231 miles on a 100% charge. After doing all that voodoo the SC told me to do to get back my miles, I am now back to 264 rated miles on a 100% charge.

Here is my question to all the smart people on the forum: Could I have driven 264 actual miles back on Nov '13 when my battery only displayed 231 rated miles if I drove conservatively so that my actual miles equaled my rated miles (about 300Wh/mile I think)? Please ignore the hidden reserve.

I don't think you can ignore the hidden reserve. Very likely the algorith change is indeed in the hidden reserve so that the car kept putting more and more conservative estimates hence if you drove past your 231 miles you could probably have gone another 33 miles with charge now message. i have in fact on two occasions driven my Model S below the charge now mention. The first time I did ca 12 km of it and by the battery gauge and used kWh I estimated another 15-20km was there... And that was after one month of ownership

 

[Trnsl8r]

I am still confused by this statement: "The physical distance you can drive the vehicle from full to empty remains the same, only the displayed estimate has changed."

As I have posted on other threads, my battery on Nov '13 showed my rated range to be 231 miles on a 100% charge. After doing all that voodoo the SC told me to do to get back my miles, I am now back to 264 rated miles on a 100% charge.

Here is my question to all the smart people on the forum: Could I have driven 264 actual miles back on Nov '13 when my battery only displayed 231 rated miles if I drove conservatively so that my actual miles equaled my rated miles (about 300Wh/mile I think)? Please ignore the hidden reserve.

Without implying that I'm one of the smart ones on the forum... but yes, that's exactly what Jerome said. The range estimate displayed on the screen is just that, an estimate. The distance you are/were able to drive remains the same (assuming status quo and no degradation in between).

 

[dave]

I drive however I like when range isn't an issue - fast, HVAC, etc. However on road trips I turn HVAC off completely and I can still never get a 1:1 ratio of miles on the dash to actual miles driven. I had hoped to plan for 265 mile legs, slowing down if conditions required. I have a regular trip to Indianapolis and back of 240 miles I was hoping to do in the Tesla, but I have never been able to come close to this and am unable to make this trip.

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

Anyways, enough negativity. I also applaud Jerome's response and am grateful for the accurate information! I still love my Tesla!

 

[Trnsl8r]

I submit that Tesla should calibrate and monitor the battery capacity in absolute energy units.
This business of introducing a rated range between owners and the real capacity of the battery just introduces confusion and uncertainty regarding the time evolution of battery capacity. I suppose it does provide Tesla with some wiggle room, but I'm not sure I want them to have that. I'd prefer that we mutually agree on what the best interpretation of battery state is at any given time, without questions about software that implements a range calculation.
FWIW...

The problem is not the unit, but estimating how much energy is actually in the battery. Jerome states that the only way accurately measure that is to fully discharge and then charge the battery (which you don't want to do), so instead software estimates it. Now whether you display that estimate in rated/ideal miles or as a percentage is not going to affect the accuracy.

- - - Updated - - -

I drive however I like when range isn't an issue - fast, HVAC, etc. However on road trips I turn HVAC off completely and I can still never get a 1:1 ratio of miles on the dash to actual miles driven. I had hoped to plan for 265 mile legs, slowing down if conditions required. I have a regular trip to Indianapolis and back of 240 miles I was hoping to do in the Tesla, but I have never been able to come close to this and am unable to make this trip.

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

Anyways, enough negativity. I also applaud Jerome's response and am grateful for the accurate information! I still love my Tesla!

One time, when hypermiling to make it to a supercharger, I averaged 285 for about 90 miles by keeping the cruise control at 53mph. (Not fun to be passed by truckers on a two-lane highway, but what could you do...)