This is an interesting point. So even though rated range does not account for driving style, it seems that nominal kWh available does. Since less energy can be extracted at higher Wh/mi, this seems to prove that the range algo is dependent in some way on driving habits.
-
Want to remove ads? Register an account and login to see fewer ads, and become a Supporting Member to remove almost all ads.
This is an interesting point. So even though rated range does not account for driving style, it seems that nominal kWh available does. Since less energy can be extracted at higher Wh/mi, this seems to prove that the range algo is dependent in some way on driving habits.
Electricfan
Active Member
Update: A Tesla spokesperson sent us the following statement:
Did it seem strange to anybody else that Tesla didn't state that the 85kwh battery is actually an 85kwh battery? They kind of do a commercial on the design, and start listing fudge factors, but they don't state that the battery really has a capacity of 85kwh.
As an owner of a car that has "85" on the back, I would rather they had said something like "Tesla markets several options of battery size in our Model S, and one of them is 85 kwh. This option contains a battery that has 85 kwh of energy storage capacity when new. It will degrade over time, but when new, the car has 85 kwh of energy."
“The battery pack in Model S is designed to meet everyday driving needs as well as provide long range for road trips. The total available energy from a battery depends greatly on conditions and can vary based on factors such discharge rate and temperature. It is very difficult to replicate the exact discharge profile at home to extract the maximum available energy in a battery pack.”
Did it seem strange to anybody else that Tesla didn't state that the 85kwh battery is actually an 85kwh battery? They kind of do a commercial on the design, and start listing fudge factors, but they don't state that the battery really has a capacity of 85kwh.
As an owner of a car that has "85" on the back, I would rather they had said something like "Tesla markets several options of battery size in our Model S, and one of them is 85 kwh. This option contains a battery that has 85 kwh of energy storage capacity when new. It will degrade over time, but when new, the car has 85 kwh of energy."
So the press conference might go like this:
The total available energy from a battery depends greatly on conditions and can vary based on factors such discharge rate and temperature. It is very difficult to replicate the exact discharge profile at home to extract the maximum available energy in a battery pack. But we found this obscure test procedure, ItReeksof 691, which we used at a discharge of .01C and temperature of 50C, and easily obtained much higher capacity than humanly possible by anyone from NC...
The total available energy from a battery depends greatly on conditions and can vary based on factors such discharge rate and temperature. It is very difficult to replicate the exact discharge profile at home to extract the maximum available energy in a battery pack. But we found this obscure test procedure, ItReeksof 691, which we used at a discharge of .01C and temperature of 50C, and easily obtained much higher capacity than humanly possible by anyone from NC...
WK,
I currently have a 85 D pack, and my observations, though not as detailed as yours, agree with yours. I do have just a little data from my old A pack which I had run the numbers on back in the day, which seemed more consistent with an 85kWh pack. If I had known that it would have mattered this much later on, I would have taken better notes.
I was able to discharge my A pack from full to 1 RM (in one drive) with a total discharge of 79.4kWh (as displayed by the car's total energy, average of 305 Wh/mi for 260.9mi).
At that end state (1RM), the pack voltage was ~317V, which on a 96 series stack is 3.3V. Because this pack Voltage at 1RM is identical to what I currently see with my D pack, I assume that the same 4kWh buffer remaining below 3.3V now was there then, yielding a total pack size of 79.4kWh + .3kWh(for that last mile) + 4kWh buffer = 83.7kWh, assuming that 0 meant 0.
Of course I could have had just an amazing pack (that I'm very glad to be rid of, but that's another story), but I think it may point to a true change in the packs total capacity very early on. It's too bad we don't have any fresh A pack cells around for you to test.
Peter
I currently have a 85 D pack, and my observations, though not as detailed as yours, agree with yours. I do have just a little data from my old A pack which I had run the numbers on back in the day, which seemed more consistent with an 85kWh pack. If I had known that it would have mattered this much later on, I would have taken better notes.
I was able to discharge my A pack from full to 1 RM (in one drive) with a total discharge of 79.4kWh (as displayed by the car's total energy, average of 305 Wh/mi for 260.9mi).
At that end state (1RM), the pack voltage was ~317V, which on a 96 series stack is 3.3V. Because this pack Voltage at 1RM is identical to what I currently see with my D pack, I assume that the same 4kWh buffer remaining below 3.3V now was there then, yielding a total pack size of 79.4kWh + .3kWh(for that last mile) + 4kWh buffer = 83.7kWh, assuming that 0 meant 0.
Of course I could have had just an amazing pack (that I'm very glad to be rid of, but that's another story), but I think it may point to a true change in the packs total capacity very early on. It's too bad we don't have any fresh A pack cells around for you to test.
Peter
Wow very close to 80kWh energy usage on the dash is very, very impressive. Even when hyper miling for 15+ hours Björn got close to 77kWh. With his regular driving he got 74kWh. People usually report 74-75kWh too. They all seemed logical and on par with WK's findings but 80kWh on the dash + feeding the 12V system, heating/cooling usages you probably used more than 80kWh on that run. How did you measure pack voltage when depleted btw? Was that the supercharging voltage when connected? I wish you had a photo of the dash.
Couple of notes:
All my testing now matches WK, Björn, and others.
While driving (i.e. car "on"), all loads such as 12V, heating, cooling, etc. at included in the displayed energy used.
Supercharger voltage with no current flowing was 317, it goes up from that once you start pushing current into the battery.
I did find a picture:
Thanks for the picture. Excuse me if I'm wrong but I may not be following here.
-WK states 77kWh usable. We thought 12V and heating weren't displayed at the energy used. 77kWh + 4 buffer = WK's 81kWh result (earlier in the thread, preheating etc. not displayed as energy usage)
-Björn got ~77kWh from a fully charged pack hypermiling. Matches WK
-Björn got 75kWh regular driving. Assuming heating and 12V is not displayed, matches WK
-You got 80kWh? +4 buffer completely defies WK's results. More so if 12V and heating is not displayed on energy usage.
Great stuff wk, I was waiting for Tesla cells real life measurements for long time, thanks! I think it disproves many theories that Tesla use some special magical chemistry in their cells.
Now for the results... it doesn't look good, I was expecting Tesla to be more honest. But in fact it's pretty much in line with most cells manufacturers misleading rating of the cells. NCR18650B cells was (at least initialy, I think Panasonic reduced it now) advertised as 3400mAh cells, but in discharge tests these cells never got to that. In the best case they were 3200mAh.
As for the cells, I don't think Tesla ever officially announced they use NCR18650B, there were rumours that it may be specially tailored NCR18650B. And in fact it never looked to be NCR18650B because this cell maximum discharge current is 2 x capacity, and Tesla S Performance can draw 4C, Ludicrous needs even more! I think the cells are more likely be closer to NCR18650BE. It's just very strange IR is higher than NCR18650B.
Now for the results... it doesn't look good, I was expecting Tesla to be more honest. But in fact it's pretty much in line with most cells manufacturers misleading rating of the cells. NCR18650B cells was (at least initialy, I think Panasonic reduced it now) advertised as 3400mAh cells, but in discharge tests these cells never got to that. In the best case they were 3200mAh.
As for the cells, I don't think Tesla ever officially announced they use NCR18650B, there were rumours that it may be specially tailored NCR18650B. And in fact it never looked to be NCR18650B because this cell maximum discharge current is 2 x capacity, and Tesla S Performance can draw 4C, Ludicrous needs even more! I think the cells are more likely be closer to NCR18650BE. It's just very strange IR is higher than NCR18650B.
JRP3
Hyperactive Member
Is there any evidence that newer 85kWh cars are more efficient than the original 85kWh cars, enough to make up the missing 4kWh or so? That same premise was brought up earlier in this thread with no good supporting evidence.
Ulmo
Active Member
Annnnnnnd .... the post right after mine with me saying if it were me I'd take the easy road if I were them, instead shows they chose the hide under the rug road. That has nothing to do with me. It speaks for itself.
By the way, taken out of context, like the news media loves to do, everything they said was true. But in context: any logical person will know what it represents. (I'm too afraid to say it out loud because I'm a supporter and intend to be a future non-difficult customer. Serious: I'll be a fantastic customer. I won't be a hassle. I'll be profitable, and an enthusiastic user, always extolling the benefits of the brand and technology and purpose. I'll also be a real customer, not just a pin cushion. And even if pins are pushed into me, I'll quietly yield to let others take over my steed (sell it quietly) and I'll divert elsewhere (S550?) and happily come back when things are better, so I'll never be a thorn in anyone's side.)
What do I personally take from this? Buyer beware. But that's ALWAYS been true. So to me, nothing's changed about my approach, and all that has changed is I know the current status of the horse race. I still believe in the mission. I just have to keep to my own personal goals at the same time. And honestly, that hasn't changed, either: the top-end car today goes the same distance in the same conditions that it did yesterday, regardless of model name. And same for a used variety, if that's the route I go. I'm actually not turned away by this. But it also means unless I see it in writing, I won't think it's something I can hold anyone to; everything will be as-is. All I'll care about is getting there safely and timely whenever I use it.
Today my ICE car started wobbling on the roads. Scared the heck out of me. Turns out I think I had a heavy load in the trunk that was shifting from side to side, causing the car to swing out in the tail end every turn (approximately 50 pounds, hitting the side of the trunk, pushing my car out hard). It was a spare gas can full of gas. Will we still have issues with electric cars? Yes. Will we have issues of spare gas cans sloshing back and forth in the rear compartment? No. Will we have range anxiety? Yes. Will Teslas be able to use the SuperCharger network? Yes. They just opened up two that I would love to use about once a month or so. I think it's still a compelling product, regardless of this issue. But it's also nice to know where the lay of the land is, so to speak, so I know how to navigate it without troubles.
It's just my speculation.
2013, 2014, 2015 Model S 85 all had the same EPA 265 miles. If the 85 had 85 kWh back in 2013 and now only has 81 kWh, at least based on EPA rating of the mileage it does indicate an increase in mile/kWh over the years.
From Fuel Economy
Compare Side-by-Side
2013, 2014, 2015 Model S 85 all had the same EPA 265 miles. If the 85 had 85 kWh back in 2013 and now only has 81 kWh, at least based on EPA rating of the mileage it does indicate an increase in mile/kWh over the years.
From Fuel Economy
Compare Side-by-Side
Ulmo
Active Member
This plausibly seems like a really good idea. The downside in marketing is that the salespeople would always have to explain that those are ideal rated miles, not towing, not going uphill, no headwind, nice sunny but not TOO sunny California day, not too hot and not too cold, no rain, i.e., the type of things most of the nation sneers at. But your idea has me thinking about some creative ways of marketing it. Such as:
Model 3 200im, 250im, 150im. IM would stand for Ideal Miles. Salespeople would always say "Realistic miles in your situation would be different than Ideal Miles. If you go 45MPH downhill with a tail wind in temperate weather, you'll get more than IM, otherwise you'll likely get less going 80MPH uphill with a headwind in cold weather and light rain, which we don't recommend you do since that's awfully fast to be driving in rain." The Model S would be the Model S 230im-D, the model S 286im-D, and the Model S 268im-PDL, and so on. Every PDL customer would know going full throttle won't give them 268 actual miles. If anybody says "but I'm not getting 286 miles", everyone (including Tesla) can just point and say "that's IDEAL miles --- I bet if you drove 55MPH on a 70 degree day on a straight road with no wind or rain, you'd get every last one of those 286 miles." As a matter of fact, you would quickly learn that 286im means a bucket of potential, out of which you scoop at your own rate, and people would pretty quickly settle down and like it.
That way, Tesla would be free to improve upon mileage and chemistry of the packs all they want, without having to tell us exactly what the spec curves are. Actually, Tesla might want to TEST what the spec curves after selling the cars to us, as they've STATED they are actually doing with the "90" packs, after just doing an "ideal miles" measurement (EPA range, basically) to sell us the cars in the first place.
You can only ask Tesla to do so much. Physics will do the rest, after Tesla had its chance to engineer the product. Tesla can't control every single variable of cars that are going to outlive their own development and testing of the cars. But, they could do some measure better of being transparent about what they do know, if they choose to market it that way. Most of us would like that, but not every sales team has the same approach.
JRP3
Hyperactive Member
There us no evidence of this. I'm quite sure the "85" pack, whatever the actual size was originally, is still the same today.
Yeh, like I said, just my speculation.
- - - Updated - - -
On the other hand, the salespeople will still need to give the potential customer a number of IM if the car model is based on the advertised battery size. And then go through all the explaining of IM. Although opinions vary quite differently in this thread (too many posts I haven't finished each one and honestly don't plan to after 10 pages...), I think we can all agree Tesla should be clear about what they put on their marketing materials, even with asterisks.
- - - Updated - - -
On the other hand, the salespeople will still need to give the potential customer a number of IM if the car model is based on the advertised battery size. And then go through all the explaining of IM. Although opinions vary quite differently in this thread (too many posts I haven't finished each one and honestly don't plan to after 10 pages...), I think we can all agree Tesla should be clear about what they put on their marketing materials, even with asterisks.
Lets take a quick look at heating. When preheating, the car is NOT "on" and that energy used is NOT counted in the energy used display. When heating the car while driving (the car is now "on"), that energy is counted in the energy used display. Similar to this is the 12V/vampire draw, when the car is NOT "on", that energy is NOT counted in the energy used display, and when the car is "on" that energy used is counted in the display. This is fairly easy to verify by anyone questioning it, just set up a short loop, say 10 miles, reset a trip counter, roll down the windows and turn the heat up to max and drive the loop. Record the data, and then reset the trip data. Take the exact loop again with climate control off. You will see a bit over a 1kWh usage difference, or about 100wh/mi greater energy usage.
This data is from a very early pack back in 2012. I don't believe that my results defy WK's, as he doesn't have an old A pack to test as far as I know. All my newest data on this match WK's data.
Peter
Cottonwood
Roadster#433, Model S#S37
74.4 with 5 rated miles left is 74.4kWh + 5mi*0.3kWh/mi is 75.9 kWh.
Here is a picture from my P85D after a hypermile drive when the car was about 3 months old with one stop from P85D Range Records
I started at 99%; let's call that 2.5 rated miles less than 100%. 71.4kWh + (12mi+2.5mi)*0.3kWh/mi is 75.75 kWh. Pretty consistent with tezzla's 75.9 kWh...
Similar threads
- Question
