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How much you're varying your foot position wouldn't matter that I can see - provided the car has enough power on the active motor (presumably the taller front motor) to answer your request.
Until you're asking for more than ~200 horsepower (or slipping due to low traction conditions) you'll never know the difference (unless you're doing enough canyon carving to feel the subtle difference in chassis handling - but that's presumably mostly at lower speeds where the car might prefer the rear motor anyway.)
I guess a lot of this depends on how quickly the car can recover an idled motor. I'm assuming that idling a motor is basically instant - you just cut the drive fields and let it freewheel. But I'm not sure how long it takes to recover from that - possibly determining the correct phase and establishing the right slip rate without inducing torque transients takes a few revolutions (which would still be a small fraction of a second for a motor that's spinning at 8k rpm.)
Walter
MartinAustin
Active Member
I know, I know... if only more of us would pay attention to you SteveG3 :biggrin:
No-one saw this extra Elon Tweet yet?
"85D has higher range than 85 when using the same tires. Sport tires have better handling, but 3% to 5% range impact. Tradeoff is worth it
"
JRP3
Hyperactive Member
I'd guess the inverter would just go into zero torque mode until the throttle request demands X amount of power above what the other motor can deliver. Should happen at the speed of electrons, or close to it. The slight delay probably explains "Normal" mode.
Well I'm feeling much better. Thank you Elon. Makes perfect sense. Unfortunately I'm about to go on a road trip and could really use normal mode! The longest stretch will either be on 12/26 or 1/3. Maybe the update will come out while I'm on my trip.
dennis
Model S Plaid
Absolutely not true. Here is the exact language from SAE J1634, Revised OCT2012, pg. 16:
If multiple charging power levels are available, the vehicle shall be recharged at the power level recommended by the manufacturer. If not specified by the manufacturer, the recharging power level
expected to be most widely utilized by end users shall be selected. Once the correct power level has been determined for a vehicle, it shall be consistently used for all pre- and post-test recharging events.
No mention of a 10% penalty. No mention of averaging. Just the manufacturer recommended level, or if not specified, the most widely used level.
You can be certain that if the EPA changed the procedure and Tesla got lower numbers, that would have explained the change in testing procedure. As breser has pointed out several times, the EPA range for P85/P85+ with 21" tires was never tested. We now know that is an 8 mi range penalty, so the delta is 15 miles, not 23.
I agree there is still no explanation about the MPGe discrepancy, except possibly the tweet from Elon. But PLEASE do not further propagate the idea that the EPA changed their testing procedure. They didn't.
Hmm. Interesting language. Isn't 90% Tesla's recommended charging level and the level most people use?
That'd mean basing the AER on 90% charge would be correct, per the procedure - and consistent with both the 242 EPA range and the 89 MPGe EPA combined efficiency.
With this chain of reasoning, the ~10% change in EPA rating is all on paper, and when you range charge it should go right out the window. But if that's the case, why did Tesla adjust the rated range to reflect 242 @ 100%?!?
Walter
Given Elon's tweet today about a forthcoming update that will allow the car to disable a motor while cruising clearly shows that a MAJOR change is coming, and any range estimates, and actual ranges that the first P85D owners are seeing now is not reflective of what is to come.
For now, the best move is to just wait and see.
breser
AutoPilot Nostradamus
I disagree pretty strongly and we've been over this on the range thread on the order sub-forum. Tesla already solved the problem that Nissan had with 2013 LEAF by adding the slider. Nissan either couldn't, wouldn't or didn't think of doing something similar. Given that Nissan's solution was to remove the 80% charge in the 2014 model year I suspect one of the former two reasons.
The numbers for the Model S range came out in 2012 so many people theorize that these weren't based on the latest rules. The problem with that is that the rules were adopted in 2011 (effective with the 2013 model year), far enough in advance for Tesla to test using them. If there was a rule change since those rules Tesla would have to updated their range numbers. We saw this en masse when the EPA changed from the 2-cycle to the 5-cycle test process with the 2008 model year. Cars with old test results had to be tested under the new test procedure and even cars that had no significant changes between model years saw mileage figures change.
This math is not even remotely comparable to actually what is done to come up with the range and MPGe. You can't just take the range and divide it by the combined and then use that factor to figure out what the combined should be. The combined MPGe is made up of 55% city and 45% highway. Reading the test procedure (SAE J1634) they come up with a city and a highway range. But I haven't been able to figure out how they combine those, it may very well be the 55%/45% split that matches the MPGe numbers. But I haven't found where that combination is described. I think it's buried in the CFR parts that I haven't read fully yet.
But ignoring that you're still doing the math wrong. You can't compare the 265 number reported for the S85 (on 19" wheels) to the 242 reported for the P85D (on 21" wheels). What you have to do is compare the 250 number. That comes up with nearly 84 (still not as good as you'd expect). But it's getting closer.
Something I've mentioned before in other posts about this is that we may be looking at the software limitation on power taken out of the battery kicking in. If this limitation did not exist in the software the tests were run with back in 2012 before the Model S release but do exist in the tests run now for the P85D/85D then that could help explain some of these differences. We have good reason to believe that changes were made here because there were reports of people "bricking" cars soon after the Model S came out that have gone away. Some posts on this forum recall being able to pull more power from the battery before it stopped earlier than now. I've seen a lot of people lately saying 11 kWh are reserved and someone said they recall being able to pull 80 kWh out of the battery a long time ago. If so that's a potential decrease in Usable Battery Energy (to use the term used by the SAE J1634 standard) of 6 kWh.
But that's not a change in any sort of test procedure from the EPA, that's a change that Tesla made. It represents a real decrease in the range of the vehicles (though not the efficiency). Tesla is unique in the ability to update the software to the fleet via over the air updates (at least to the extent that it impacts major driving functionality, some cars have OTA updates to infotainment). The regulations were not written and have not been updated to reflect the nature of cars with such software updates. They don't require testing unless actual physical components are changed and even then only very specific components. Heck they don't even require testing if the body of the car changes [1].
I posted about this back when I explained why the P85D has the rating on the window with the 242 number (21" wheels). Specifically that the S85/P85/P85+ are the same vehicle configuration and as such as long as less than 33% of the cars have 21" wheels then they don't have to include them in the test configuration.
So I think the 242 number is made up of 2 or 3 components:
1) Decreased range due to the 21" wheels vs 19" wheels that were tested with older vehicles. Tesla has told us that this is a difference of 8 miles (given the 250 mile number for the P85D with 19" wheels).
2) Software updates since when the S85 tests were run that limit the amount of energy removed from the battery more so than in the past. This would decrease the range without change the efficiency of the vehicle.
3) Decreased range due to the current software on the P85D that drives both motors when it could shut down one. We don't know how much of an impact this is and we don't know if it is reflected in the window sticker numbers. It's possible that it is and that Tesla will be able to revise the stickers once the software update has been made. This may require some negotiation with the EPA because the regulations don't envision this. But it's also possible they're using software that already has these improvements during the tests. The test procedures allows them to use prototype vehicles. It does not have to be a production example. It says nothing of software, but I think it's fair to think if you can use prototype hardware you can use prototype software.
This leaves an interesting question. Do these 2 or 3 factors alone allow us to come up with the 242 range from the MPGe numbers?
We know what how to handle the first issue, just use 250 instead of 242. That extra 8 miles of range lost is accounted for. But can the extra 15 miles be accounted for by figuring an extra reserve of 6 kWH?
Tesla tells us that all the cars use 38 kWh per 100 miles or 0.38 kWh per mile. 6 kWh / 0.38 kWh per mile = 15.789 miles.
So in conclusion I conclude that the unaccounted for reduction in range is a result of Tesla deciding to reserve 6 kWh more of the battery. It's not a test procedure change.
The added decrease in range over the window stickers (that actual owners are reporting) appears to be accounted for by third issue above.
[1] EPA may change fuel economy guidelines after Ford MPG reboot | Fox News
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You say my simple math doesn't work, but it does. Those numbers don't add up, the mix of city / highway is irrelevant. 21" tires are irrelevant. The final MPGe needs to be 81 to get to 242 at 100% battery cycle. It isn't. Is there actually some source that confirms that Tesla upped the reserve? I'm not contesting its validity just wondering to the quality of the additional 6Kwh reserve info. I'm having a hard time believing that 6kwh reserve was just sucked away and no one noticed or that they did that just for the EPA test.
I know that now they are claiming a range reduction for 21" rims. When I ordered my P85+ they claimed an additional 10 miles of range with the 21" rims (required) and the plus suspension, which the D reportedly has. It really doesn't matter in the calculations I did. The problem is we have lots of conflicting information and a bunch of speculation. I actually think the wording on J1634 doc pretty much says they have to use the standard charge of 90%. Tesla recommends this charge level for daily driving. Case closed from my perspective.
dennis
Model S Plaid
Tesla's recommended level of charging for a roadtrip (where range matters) is 100%. In fact, the instructions under the slider where you set charging level say "TRIP: Useful for a road trip. Charging to this level will take longer". As stated above, if there is a manufacturer recommended charging level, that is the level that is to be used for charging according to SAE 1634. The "most widely used by end users" charging level only comes into play if there is no manufacturer recommended charging level.
Seriously Walter, given the footnotes on the Tesla site about 21" wheels and subject to EPA verification, don't you think that if the P85D EPA test was done at 90%, and the S 85 test was done at 100%, that Tesla would have footnoted that fact as well??
My best guess as to what happened with the P85D range.
Tesla originally tested the Model S in 2012 before the J1634 amendment which required the recommended charge level for the EPA range calculations. Model S EPA range is 265. This is very well documented both cause and effect with the Nissan Leaf. It exists and it's real.
They plan on announcing the D and want to showcase the "Insane" performance, the drive train team focuses on the "Insane" mode. Normal mode isn't a focus and receives little testing.
Tesla announces the D and starts taking orders planning on shipping in December.
Uh Oh they need to retest and prepare updated Monroney stickers. This was the first reported delay on shipping P85Ds. At this point they realize they have to adhere to J1634. They consult their legal team and the risks (fines) are substantial. You either remove the ability to select a charge level or do the EPA test at the Tesla recommended charge level. The recommended charge level is 90%.
There is also a problem with "Normal" mode because it hasn't had much testing. They need another month or two to get it right. They decide they will ship "normal" in an update. They test at 90% on 21" rims in sport mode and arrive at 242.
Since rated refers to EPA rated range, they decide that the safest thing to do from a EPA compliance perspective is to show rated range as the EPA rated range of 242. Customers can always choose to show ideal mode if they wish. Efficiency will return with the update that includes a "Normal" mode.
Elon tweets about the update.
EPA rated range will be retested in the future using "Normal" mode if they think it will increase range enough to be worth the effort.
- - - Updated - - -
Tesla has not historically been very good about updating their website with accurate clear information. Besides if they put a nice footnote on there explaining everything we wouldn't have all of these threads and conspiracy theories.
It's not trip. "If multiple charging power levels are available, the vehicle shall be recharged at the power level recommended by the manufacturer." The recommended charge level is 90% or below. Tesla most likely got a written clarification allowing them to use 90%. The EPA here is in a twisted way trying to be fair. The logic is there. They want to show typical range for typical users in a typical situation. That would not be a trip charge, It would be the recommend charge level. Plenty of Nissan documentation to the realities of the EPA recommended charge levels.
Tesla originally tested the Model S in 2012 before the J1634 amendment which required the recommended charge level for the EPA range calculations. Model S EPA range is 265. This is very well documented both cause and effect with the Nissan Leaf. It exists and it's real.
They plan on announcing the D and want to showcase the "Insane" performance, the drive train team focuses on the "Insane" mode. Normal mode isn't a focus and receives little testing.
Tesla announces the D and starts taking orders planning on shipping in December.
Uh Oh they need to retest and prepare updated Monroney stickers. This was the first reported delay on shipping P85Ds. At this point they realize they have to adhere to J1634. They consult their legal team and the risks (fines) are substantial. You either remove the ability to select a charge level or do the EPA test at the Tesla recommended charge level. The recommended charge level is 90%.
There is also a problem with "Normal" mode because it hasn't had much testing. They need another month or two to get it right. They decide they will ship "normal" in an update. They test at 90% on 21" rims in sport mode and arrive at 242.
Since rated refers to EPA rated range, they decide that the safest thing to do from a EPA compliance perspective is to show rated range as the EPA rated range of 242. Customers can always choose to show ideal mode if they wish. Efficiency will return with the update that includes a "Normal" mode.
Elon tweets about the update.
EPA rated range will be retested in the future using "Normal" mode if they think it will increase range enough to be worth the effort.
- - - Updated - - -
Tesla has not historically been very good about updating their website with accurate clear information. Besides if they put a nice footnote on there explaining everything we wouldn't have all of these threads and conspiracy theories.
It's not trip. "If multiple charging power levels are available, the vehicle shall be recharged at the power level recommended by the manufacturer." The recommended charge level is 90% or below. Tesla most likely got a written clarification allowing them to use 90%. The EPA here is in a twisted way trying to be fair. The logic is there. They want to show typical range for typical users in a typical situation. That would not be a trip charge, It would be the recommend charge level. Plenty of Nissan documentation to the realities of the EPA recommended charge levels.
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dennis
Model S Plaid
I have a couple of issues with your "best guess":
1) The Tesla recommended charging level for a road trip is 100%, not 90%. The Tesla recommended charging for daily use is not 90%, it is 50%-90%. It is right there on the slider.
2) If the P85D EPA test was done at 90% charge, and the older S85 EPA test was done at 100% charge, why hasn't Tesla told us that? It has more impact on the stated range number than the difference between 21" rims and 19" rims, which they have pointed out ever since they had an EPA number for the P85D. And don't you think that Elon would have tweeted than long before he tweeted about the forthcoming motor optimization?
I don't purport to understand why the number is 250 rather than 265. I'm just trying to squash the continued unfounded speculation that it is because Tesla was only able to charge to 90% when they did the P85D EPA test.
I'm not sure what to think. They data we've been provided doesn't appear to all fit together into a simple picture. I'm hopeful that Tesla will provide a blog post explaining it all.
Right now the simplest explanation I have for all of the observed data is that they are testing a 90% charge. It is certainly not the only possibility. As far as foot notes go, they don't provide any others about the EPA test procedure - not that this is any reason they couldn't give such a helpful footnote if they choose to.
Walter
dennis
Model S Plaid
I agree that it doesn't make sense, and hope like you that they will explain the difference between the 2012 EPA test of the S 85 and the 2014 EPA test of the P85D. I'm skeptical of the simple explanation of the 90% charge because whenever Tesla has any number that casts them in a bad light (242 vs. 265, for example), they go out of their way to spin the numbers in their favor. If it was as simple as a lower charge level of the battery, we would have already been told that by Tesla.
stopcrazypp
Well-Known Member
The reason why 242 is the proper number to use and not 250 is because 242 is what is written on the Monroney sticker in reference to the 86MPGe city / 94MPGe highway / 89MPGe combined; the 250 miles may have a different MPGe number (don't know yet until we see a sticker with 250 written on it):
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Andyw2100
Well-Known Member
dennis
Model S Plaid
I'm leaning more and more toward @breser's theory that the discrepancy between the various EPA numbers can be explained by less usable kwh from the battery being available now vs. in 2012 when the original S85/S60 EPA tests were done. Looking at he current EPA numbers on the Tesla website:
S85 - currently unchanged at 265. Tesla is not required to rerun the EPA test because there has been no change in the hardware
S60 - currently unchanged at 208. Same as above.
S85D - 265. But Tesla said that the AWD S85D was more efficient, so it should have a higher range. But if there is less usable battery available, that would explain the discrepancy.
P85D - 250 (with 19" wheels), 242 with 21" wheels. Given that it weighs 250 lbs more, you would expect the P85D to have less range than the S85D, both of which benefit from any range improvements due to AWD. But both are being tested with the latest software which possibly makes less battery available.
In support of this theory, IIRC the wh/mi to achieve the rated range of 265 miles dropped from 308 to 291 somewhere around the 5.0 software introduction. This could easily be explained by there being less usable battery vs. the prior software releases.
This is just a theory, but I believe it is supported by the data, including 89 MPGe resulting in 242 miles of range on the P85D (2014) and 265 miles of range on the S85 (2012).
S85 - currently unchanged at 265. Tesla is not required to rerun the EPA test because there has been no change in the hardware
S60 - currently unchanged at 208. Same as above.
S85D - 265. But Tesla said that the AWD S85D was more efficient, so it should have a higher range. But if there is less usable battery available, that would explain the discrepancy.
P85D - 250 (with 19" wheels), 242 with 21" wheels. Given that it weighs 250 lbs more, you would expect the P85D to have less range than the S85D, both of which benefit from any range improvements due to AWD. But both are being tested with the latest software which possibly makes less battery available.
In support of this theory, IIRC the wh/mi to achieve the rated range of 265 miles dropped from 308 to 291 somewhere around the 5.0 software introduction. This could easily be explained by there being less usable battery vs. the prior software releases.
This is just a theory, but I believe it is supported by the data, including 89 MPGe resulting in 242 miles of range on the P85D (2014) and 265 miles of range on the S85 (2012).
But that doesn't account for the latest info. "Range of P85D should then closely match P85+." That implies that when it runs in one motor mode (normal) it's going to get the same 265 mile range (On the dash anyways) as p85+. "Sport tires have better handling, but 3% to 5% range impact. Tradeoff is worth it
". He's just saying that it is actually a little more efficient but that the tires on the performance P85D model brings it back down to 265 miles ish. It also implies that the P85D's have been running in 2 motor 4 wheel drive mode all the time when in sport and insane mode and it's going to be a more dynamic in "normal" mode. At least that's my interpretation on it!
P85D normal = 265ish miles? It's not that much higher because of the tires.
S85D normal = 275-280? Assuming it's on 19's, not the same sport tires, and it has a smaller motor for the one motor idle mode.
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