Dec 29, 2014
wk057 Edit: Results start here: P85D vs. P85 Efficiency Testing - Page 6
Edit: Data entry here: P85 vs P85D Efficiency Data - Google Sheets
So, the details around my upcoming efficiency head-to-head have been somewhat scattered around the forum in various threads. Tomorrow is looking like it is going to be the day to actually do the test since it should finally be clear all day weather wise. High temp is predicted to be a bit low, low 50s, but this shouldn't impact the test since climate control will be off on both vehicles and both will be preconditioned from wall power prior to setting out.
As many of you know, both myself and my fiance have our own Model S's, which puts me in a somewhat fortunate but relatively unique situation where I can easily do side by side tests and comparisons.
Test subjects, with notable differences noted:
- 2014 Tesla Model S P85D, fully loaded except 3rd row seats
- 21" Silver rims with Michelin Pilot Sport tires, 245/35/R21 in the front, 265/35/R21 in the back
- Air suspension
- Just under 1,000 miles on odometer and tires
- 2014 Tesla Model S P85, my fiance's, also pretty much loaded
- 21" Grey rims with Continental Extreme Contact tires, 245/35/R21 all around
- Coil suspension
- Under 8,000 miles on odometer and tires
For the air vs coil suspension, for normal driving this should not effect efficiency. Since I believe the P85D is at an efficiency disadvantage based on my existing data I will have its air suspension set to always low for the test. The sport tires on the P85D are rumored to be less efficient than the tires on the P85. The P85D also has wider rear tires than the P85. I'll see how the final numbers come out. If a reasonable margin for error due to the minor differences makes it too close to call, then well, that is the result. Obviously these are not identical vehicles, but the differences should be minor enough to show any gross efficiency differences that can't be accounted for by the small differences between the cars.
I have two GoPro cameras and a dash cam in each car. I plan on syncing the video from all of these and making a four-panel video of the test, possibly time lapsed on the boring parts. The dash cams will view the road ahead. The GoPros will be clipped on the center divider on the pano roof to the left of the driver and aimed at the dash display (this is the plan anyway, but I'll make sure it ends up somewhere that the dash is clearly visible... working on this now actually). The dashes will show the trip meters and the 5 mile energy efficiency graph as the two "apps."
I'm still tweaking the details of the trip to make sense, but the plan is to take the same route that includes some non-highway, decent stretch of highway (~20-40 miles), some more non-highway, arrive at a destination, allow both cars to sit for the same amount of time while we're there (the plan is to meet and pick up a couple of friends while we're out that way, one to ride back with each of us), then do the reverse of the trip. The plan will be to use the cruise control on the highway set to various speeds for 5 to 10 miles at a time. I plan to follow the P85 with the P85D for both parts of the trip, also. Combined with the air suspension set to low, I think this should offset any potential differences caused by the different tire configurations.
Some things that come to mind for setup for both cars:
- Ensure cold tire pressures are correct before departure
- No cabin climate control (jackets, gloves, and seat warmers only)
- Range mode enabled
- Sport mode setting on the P85D for acceleration
- Traction control On on the P85 (should go without saying)
- All windows closed
- No cargo
- Regen set to standard
- Very limited use of friction brakes
- No P85(D) shenanigans (ie: acceleration within reason)
- Charge both cars to 90% overnight, then set both to 95% in the morning
- After charging, precondition both cars via app at 75F until preconditioning automatically shuts off
- FLIR pics before departing, at the destination, and when returning
- If possible I'm going to have Visible Tesla logging for both cars, although the API hasn't been as predictable lately as it used to be for some reason.
Should be a pretty fair test I think. Anything else simple to be added to my list to make it as controlled as possible?�
Dec 29, 2014
techmaven Wow. Thanks for doing this.�
Dec 29, 2014
pgiralt This should be a great test. Only other thing I can think is to maybe set some limit on the max power you will use when accelerating (say maybe 60 or 80 kW) so that both drivers will use similar acceleration profiles. Also, maybe to offset any driver differences, swap drivers on the reverse trip. I would think these things should be minor compared to the long stretches of driving. I think for road-trips, the most important piece of data will be the wh/m usage on the expressway. Maybe do separate 5-minute stretches at 65 mph, 70 mph, 75 mph, and 80 mph. A 5 mile stretch should give you a good enough period to get a wh/m number for each of those speeds.�
Dec 29, 2014
wk057 The route I have planned should allow for most of this. Speed limit is 65 and 70 MPH. I probably won't do a test at 80 MPH since that seems to be the police-attention-getting threshold. 78 MPH is likely though. There is a ~2 mile work zone on the route that I'll probably drop us to 55 or 60 through, but other than that it should be pretty clear on a Tuesday afternoon.
Swapping drivers on the way back actually isn't a bad plan, although my fiance has expressed her annoyance at the reversal of the turn signal and cruise control stalks between our cars... which hopefully wouldn't foul the tests. I'm still not 100% used to it either.
For acceleration, I was thinking keeping acceleration below 1C (85kW) would be reasonable. This would keep resistive losses in the battery low as well.
The highway is not perfectly flat on this route, so, averaging out over 5 to 10 miles per speed setting will make sense. Net elevation change between here and the destination is only about -50 ft. So, +50 ft on the way back. However, that doesn't tell the whole story. EV Trip Planner shows the total Up Feet and Down Feet to be just under 2000 ft. Decent bit of hills on the highway. This is real world stuff, not a test track. These are the results that actually matter.�
Dec 29, 2014
Bighorn When the P85+ came out, the staggered 21" set up was supposed to provide improved efficiency, (3%?IIRC) vs the P85.
Does the P85D have an Ideal mileage setting? Seems like it shouldn't since it was a throwback to the 2-cycle EPA testing. (Edit--on further review, it's likely based on 55 MPH testing; the 2-cycle test yielded 320 miles)
I've been curious what the Wh/rated mile rate constant is, which you'll have good documentation of if you're videoing the Trip Meter and rated mileage. Should be 275+/-5 for the RWD and 310+/-5 for the P85D.
I would abbreviate any stops for changing drivers, etc so that any unrecorded energy usage is minimized.�
Dec 29, 2014
wk057 Well, looks like the hardest part is going to be finding a good place to mount the GoPros!
Turns out clipping it to the center beam there is way to far back to see any detail on the dash... so, need to find a good close place to mount it that still allows safe driving... hmm.
Edit: Yeah, tried a few places... not really any good places to put the camera that has a good view of the entire dash without obstructing that view for the driver... going to mount it on one side at an angle probably with the sticky tape and get half of it at least (trip meter plus speedo). The graph is visible, but the numbers aren't readable.�
Dec 29, 2014
darthy001 I also clearly remember claims from Tesla that the plus-package for the P85 actually was supposed to slightly increase range. It actually said so in the design studio. So according to Teslas own claims a P85+ should have better range than a P85.�
Dec 29, 2014
wk057 This doesn't make me feel more optimistic about the P85D claims, since AFAIK the P85+ was not actually more efficient...
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Found a decent GoPro position, but requires using one of the sticky mounts on my CF trim... not 100% sure about that. Anyone with any experience?�
Dec 29, 2014
dan-l To largely eliminate rolling resistance as a variable you might consider swapping the front wheels for tomorrow's test.. Although I also recall reading that the TPMS has been updated so maybe the better idea is just to try and find the RR specs. (I looked but only found a tirerack write up based on a 400 mile consumption test.)
If one of you follows the other I'd actually recommend the same driver follows after the car swap. This should help minimize some of the differences resulting from aerodynamics (drafting) and driving style (as follower vs leader) differences.
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I think the claim was in comparison to the original 21" setup. Another thread here..
http://www.teslamotorsclub.com/showthread.php/22009-Increased-range-of-P85-over-P85�
Dec 29, 2014
CHG-ON I think doing three round trips might get better numbers. It could bring up some variables that you didn't see before. Clearly the more you do, the more accurate you will be. Not sure if you have the time for that.�
Dec 29, 2014
Andyw2100 Really? How did you pick three instead of two or nineteen?
I think wk057 is doing way, WAY more than enough already. He is trying to provide a level of detail and precision far in excess of what the disparity in numbers we all expect he will find warrant. Here's what I see as a fitting analogy: wk057 is trying to provide data good enough for us to tell which of two fast runners trying to beat out an infield grounder for a hit was out by half a step and which was safe by half a step, when in reality you've got two runners, running the bases as fast as they can, starting at the same time, and one is going to cross home plate while the other is rounding third.
I think he is doing more than enough with what he has planned. Any more is just overkill at this point. That's my opinion, anyway.�
Dec 29, 2014
AWDtsla You have a FLIR camera? In that case you are making this way more complicated than it needs to be. Rent an hour of AWD dyno time, run the cars in cruise control at the same speed for x minutes. Use the FLIR camera to check the temperature of all electronics and moving parts. You can roughly integrate temperature over volume to get a comparison of wasted energy.
100Wh/mi WILL show up somewhere, it's a massive amount of heat. If it's in the tires, then the tires will be hot, etc.
edit - you will know EXACTLY where the extra energy is going, whether it be in the inverter(s), battery, motors, tires, bearings, transmission, etc. At 65mph on a dyno that's 6.5kW of heat being dissipated. Hell you could probably do it by feel alone.�
Dec 29, 2014
wk057 That's actually not a bad idea. I might do that next.
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Mounted one GoPro in the P85D so far. Decided to brave the sticky tape mount on the CF dash trim. Using that plus a plastic bendy snake gopro mount extension.
�
Dec 29, 2014
Bighorn I don't know about others' experience, but when I use evtripplanner, my P85+ is better modeled by using data for 19" rather than 21" wheels.�
Dec 29, 2014
Chris_WDO
Why not use the suctioning mount on the left side window? Should be easily removable and adjustable. Of course, there shouldn't be driving situations where you have to lower the driver window
Sounds like a well thought, reasonable test setup! I'm curious what findings you will get!�
Dec 29, 2014
CalDreamin Might want to establish a conservative distance between the vehicles ahead of the P85 and P85D to minimize drafting effects. Drafting Behind Trucks: Does it Work? : TreeHugger�
Dec 30, 2014
Vger I saw this posted somewhere earlier, but I had the same thought:
In addition to the comparison testing, it would be interesting for someone with a P85D to do a test to try to determine, in reasonably "average" conditions (no huge headwind, very cold temps, etc.) how much one has to hyper-mile the P85D to get it to show a) the 380 Wh/mi the EPA range implies; b) the 300 Wh/mi that an S85/P85 needs to do to get its EPA-rated 265 miles.�
Dec 30, 2014
jerry33 Every permutation you use needs another pair of runs, so it gets to be quite involved. And sometimes--even when you know what the outcome should be and have only one variable (e.g. tires)--you obtain the opposite results (temporary wind condition that wasn't picked up on but lasted for a few minutes during one of the runs).�
Dec 30, 2014
NOLA_Mike My recollection on that was the P85+ with 21" wheels had better range than the P85 with optional 21" wheels due to getting Michelin Pilot Sport PS2 tires versus the tires that came on the P85.�
Dec 30, 2014
wk057 Tried this... it doesn't seem to want to stay for some reason. Actually, I think my suction cup mount is broken, and I only have one.
�
Dec 30, 2014
Johan You're mirroring my thougts exactly, here's what I posted in Elon Musk tweets software upgrade will increase P85D range - Page 10
Would be very interesting to see FLIRs after a dyno run.�
Dec 30, 2014
randompersonx Don't underestimate the ability of the cooling system to "move" this heat. In florida, after charging for a few hours at 10kw, the only heat signature I see is from the front wheels where the cooling system vents out. The rear seats are cool. (test done at 80F ambient)�
Dec 30, 2014
Bighorn The 380 EPA figure was identical on both the S85 and P85D and reflects total energy used from the grid, not battery alone--at least that's my understanding.�
Dec 30, 2014
wk057 Where are you guys getting 380 Wh/mi? 265/242*300 = ~328.5 Wh/mi for the P85D at EPA numbers...�
Dec 30, 2014
Bighorn Right off the EPA sticker--it's kind of meaningless.�
Dec 30, 2014
wk057 Well, looks like the outside temp is lower than predicted today. (Low 40s, upper 30s). I don't think this should have a huge impact on this side by side test anyway since we're using jackets and hats instead of cabin heat.
Since I may not have a chance to make another attempt in the near future I'm going to proceed shortly.�
Dec 30, 2014
Johan Could you do two tests, one with new tires on the P85D and one where you switch to the ones you have on the P85?�
Dec 30, 2014
kennybobby How much is the weight difference--how much does each vehicle weigh?
What are good values for aero coeff Cd and Area?
Has anyone done some coastdown testing--good way to determine Crr factor.
Run these in a calculation to compare predicted with his measured power.�
Dec 30, 2014
Johan Cd and Cdi is identical, no? Weight effect should be minimal, like an extra passenger or less (certainly not 100 Wh/mile).�
Dec 30, 2014
wk057 Hmm... a good side by side coast in neutral might be a nice additional to this test, down a hill on the interstate. I'll try to work that in.�
Dec 30, 2014
andrewket I don't ever recall tesla or anyone else claiming the staggered 21" on the P85+ was more efficient then the standard 21" of the P85. If anything, it would be less.�
Dec 30, 2014
Cottonwood The 380 Wh/mi on the EPA sticker is a "from the wall" number and not a "from the battery number". Also, the "from the wall" number may include vampire losses. In my P85, I have found the from the battery number for rated miles to be 290 Wh/mi, and into the battery from a DC source (Supercharger) to be 300 Wh/mi. From the wall (AC), the rated mile number is 333 Wh/mi.
For the P85D, from the battery, that would be 290 Wh/mi * 265/242 or 318 Wh/mi. Both the 290 Wh/mi and the 318 Wh/mi are about what I seen on the energy graph screen of each car.
The P85 "from the wall number" of 333 Wh/mi * 265/242 is 365 Wh/mi for the P85D. Almost the 380 number but not quite.�
Dec 30, 2014
Bighorn My from the battery rate is 275Wh/rated mile now--this has changed with time. That's how I've extrapolated the P85D to ~306. There's a little noise around that insofar as I see 74kWh available from a range charge and one P85D has seen 76.8 (317), I think. Also rated range charges have gone as high as 246-247.
The fact that the factory sticker shows 380 Wh/m for both cars seems suspect based on early results.
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The website said that when I ordered mine. I believe it was predicated on the PS2s.�
Dec 30, 2014
kennybobby If you could do it on a flat without incline would take out another factor. Both at 65 then go to neutral and coast, start a stopwatch when speed hits 60 and stop timer when speed hits 40,45, or 50. From the coastdown time, knowing weight and Cd x A, can calculate Crr for those tires.�
Dec 30, 2014
AWDtsla So any charger efficiency increases mean this number gets better. Did anybody check the P85D?�
Dec 30, 2014
Chris_WDO Ah ok....of course, if there's any way air can get under the suction cup, then theres no remedy but to replace it.
One step worth trying though (if not already done yet) is to thoroughly clean both window and suction cup surfaces with 94% alcohol on a fresh, clean piece of cloth, and let both dry thoroughly. If it still does not work, it most certainly is due to a broken suction cup.�
Dec 30, 2014
wk057 Leg one done.
Results so far are as expected. Oddly enough the P85 and P85D don't agree on range traveled so far. 56 and 55.5 miles respectively. This could explain why I couldn't perfectly follow with cruise control.
So far 313 Wh/mi P85, 365 Wh/mi P85D.
FLIR shows no major heat difference in our tires or rotors or anything else.
More soon. Getting food.�
Dec 30, 2014
breser It includes vampire losses. There are required rest periods where the car has to sit. Vampire loses would show up to some degree in those.�
Dec 30, 2014
dsm363 There is another thread about this but Tesla has a new blog post up about this�
Dec 30, 2014
Andyw2100 Blog post here: Driving Range for the Model S Family | Blog | Tesla Motors
Reader's Digest version: software update coming by end of January to give P85Ds the expected range.�
Dec 30, 2014
AnxietyRanger Tesla definitely advertised improved range for P85+ over P85 still even this summer, on their website, when I was researching the Model S purchase. I remember making special note of it, but in the end deciding I don't want the + personally. Now, I believe it was advertised as a combination of things, not simply a reference to tires.�
Dec 30, 2014
CalDreamin Compared to his P85, wk057's test showed his P85D used (365-313)/313 = 17% more energy on the same highway route.
Today's blog post by JB Straubel includes:
Sounds like the 17% energy consumption increase for a P85D versus a P85 that wk057 measured in highway driving is pretty close to what JB says is expected because the torque sleep software isn't yet installed in his P85D, and his P85D has new tires compared to the P85 he tested with 10K miles.
Thanks for conducting these tests wk057.�
Dec 30, 2014
NigelM Discussion on the new blog is over here ---> New-Blog-Driving-Range-for-Model-S-Family
Sounds to me like comparative tests are going to be made redundant until the end of next month.�
Dec 30, 2014
AnxietyRanger This is the current reality and that matters to people driving today and for the next month or so. Who knows if the month will be one month anyway, or more. The comparisons are not pointless at all. Most things matter only for a while and that's life.
A lot of nice effort has gone into documenting this for us. I for one thank wk057 for those efforts and look forward to the video. Now he can document the improvements as well then, if he wants, and we have this historical data to compare it to. One more chapter documented in the Tesla story.
Good stuff.
So, wk057, please continue your good work - it is interesting stuff the things you do, beyond this topic too of course.�
Dec 30, 2014
linkster Were tire pressures identical?
Wind or lack thereof identical?
Was the ambient temperature identical?
Was the alignment identical (performed on the same "rack" by the same tech)?
alignment was HUGE for me in obtaining high-efficiency numbers and reduced tire wear�
Dec 30, 2014
AnxietyRanger wk057 said he'd check tire pressures to be equal. If he stuck to his plan, the cars also drove at the same time, P85D behind the P85. The cars were not completely identical in spec, but both were 21" and pretty close - it is all documented in the beginning of the thread.
In any case, effort gone far beyond the level we could reasonably ask of him. This is very good info and considering Tesla's own blog post and all, quite likely very near the current "truth" as well. There was also wk057's previous experience with his own former Tesla to compare to, so as far as experience goes, he has compared the P85D to two cars, not just one.
Looking forward to the video and possible write-up from wk057.�
Dec 30, 2014
Todd Burch Wk057's experiment, if nothing else, validates the numbers JB put out.�
Dec 30, 2014
scottf200 Driving Range for the Model S Family | Blog | Tesla Motors
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Dec 30, 2014
AnxietyRanger scottf200: Then again, that 5% doesn't explain the full 17% difference - and the tires are "just under 1,000 meter" already. It is possible wk057's tires on the P85D have already been worn in by the time of this test, which might explain why his previous experience felt that there was even a larger discrepancy than 17% between P85 and P85D range?
Edit: The Elephant in the room, of course, remains how the P85(+) and P85D ranges compare when not driven on a high-way - even after the update. Interesting to see, because it probably matters to Model X as well.�
Dec 30, 2014
scottf200 I understand my future Model X cousin. (BTW, I appreciate many of your level headed post on different threads).
I would be suspicious of the difference in tires as another example. Testing two cars with the same tires would make much more sense. Not sure of the statistical difference of 265s vs 245s as one thing but they likely have different roll resistance as well with just the compound, tread pattern, and alignments.
Still I love his efforts. Very very impressive for the good of the community.�
Dec 30, 2014
AnxietyRanger Sure, clearly some level of discrepancy in this test results from the specification differences in the car. That is a fact and pointing it out is good. It is just probably a bit much to ask the guy to add to his test a rotation of tires as well from car to car. Then again, he seems so active that he might actually do something like that.�
Dec 30, 2014
wk057 Figures Tesla would put out a blog post while I did my test. lol.
Anyway, back from the trip. Both GoPros died right near the end of the trip. Mine died as I got off the highway, my fiance's died as she turned into our development. Dash cams were on 12V power, so, have that video anyway.
Going to take me a bit to sync up the videos and do a full showing of the data that way, but, here is the money shot:
P85D:
P85:
352 Wh/mi on the P85D, 306 Wh/mi on the P85. So round trip roughly 15% more energy used by the P85D. Better than I expected, honestly.
Here are starting shots. We took about a 90 minute lunch/dinner stop at the turnaround point.
P85:
P85D:
�
Dec 30, 2014
Andyw2100 I almost posted, in the wee hours of the morning, some time after my baseball post, that Tesla would probably come out with a blog post on this while you were out doing your test. Now I really wish I had. You all would be calling me Nostradamus or something.
Thanks again for all the work you did, WK057!�
Dec 30, 2014
crazybrit Are they both 21"? Oh yea, the yellow car. Sorry. OK 21s on both. I see the D is almost at 1000 miles, so we can't throw in 5% for new tires. Still looking for 5% somewhere. However, if we calculate it the other way: 306/252, it is 13%, so 3%. Still some tire break in?�
Dec 30, 2014
wk057 Yep, it's in the first post. I was actually wrong, her car only had just under 8000 miles on it. Not sure why I was thinking 9000.
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Also, due to traffic, I wasn't able to do a coasting test. I'll have to try that some other time.
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Have roughly 60 GB of video to go through... yay...�
Dec 30, 2014
Andyw2100 I'm definitely no expert, but I doubt the 5% due to new tires would be exactly 5% right up until 1000 miles, and then nothing right after that. The tires on the P85D are a lot newer than the tires on the P85. I think it's fair to assume that that does account for at least some of the difference, even if we can't quantify it precisely based on the blog post.�
Dec 30, 2014
CHG-ON I chose more than two in order to see if there is an outlier. Two won't give you that. The more you do, the more accurate the data. But you're right, picking any number of runs is pretty much a guess as to what would give the best results, unless doing a truly scientific study, where lots of work would go into determining all the parameters to a fine degree.�
Dec 30, 2014
Electrometer Thanks for running the test WK057. At 352 Wh/mi usage you probably are close to the "cruising range" of 240 miles for the P85D that JB posted in todays blog. I would guess that the torque sleep control software will give you some improvement if you run the test again.
Did you follow the same exact path in both cars? If so, then the OD readings are odd as they show a difference of 1 mile between the 2 cars.�
Dec 30, 2014
wk057 Well, was hard enough to convince my fiance to freeze for a couple of hours in the name of science.
Working on pulling some numbers from the video now. I'm going to pull the Wh/mi and energy usage numbers from the videos and put them into a spreadsheet first, post that, then I'll work on a nice video (probably something like 4x timelapse since it was ~2.5 hours of driving).
There was a 0.7% discrepancy between the P85 and P85D trip meters. At 100 miles on the P85 the P85D showed 100.7 miles traveled. Same exact route, parked in the same places, etc. No real 0.7 mile difference, so, this is something slightly different with the tires maybe? Also explains the P85 slowly losing the P85D while set at the same cruise setting. You'll see in the video later that the cars were never very far apart. On the last leg we had the cruise set to 70 for a while, and over ~30 miles the P85 ended up ahead by maybe 1/8th mile.�
Dec 30, 2014
AWDtsla Tire circumference is variable! Including factors like the rated size, pressure, wear level, current speed, current weight, current tire temperature.
It's amazing they were as close as you got them. 0.7% is tiny.
If it isn't obvious, you could have a tire that's larger in circumference, travel a longer distance, yet have the car measure more Wh/mile, when it may have been actually less!
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YMMV. :tongue:�
Dec 30, 2014
wk057 Working on inputting the "Since Last Charge" numbers from the videos into a spreadsheet for each mile. Lets me get a Wh value for each individual mile.
Once I'm done, I can apply the 0.7% discrepancy to the P85D's distance values and do a nice overlay graph that may be useful. We'll see.
About 25% done inputting the data.�
Dec 30, 2014
Bighorn Your Wh/rated mile works out to 34.1/122= 280 for the P85 and 39.5/132 = 300 for the P85D. Could be slightly confounded (underestimated) by the lunch stop.
(39.5-34.1)kWh/34.1kWh= 15.8% increased energy usage.�
Dec 30, 2014
Todd Burch The two sets of tires themselves are different (Michelins vs. Continentals), which can easily cause a difference of a few %.
Edit: the suspension differences could contribute some discrepancy too.�
Dec 30, 2014
wk057 Still typing in the data... *yawn*�
Dec 30, 2014
wk057 OK, data entry complete finally.
I'll work on doing some calculations on the data in a bit.
P85 vs P85D Efficiency Data - Google Sheets�
Dec 30, 2014
Bighorn Why does your P85D data go to 42kWh instead of 39?�
Dec 30, 2014
wk057 I'm not seeing this...?
Last entry for P85D is 39.0, when the GoPro went dead.�
Dec 30, 2014
Bighorn Sorry, on line 112, I mistook Trip B miles for Energy. Your first 46 fields seem to be duplicates and then something goes awry at line 47. Either that, or I'm reading it wrong.�
Dec 30, 2014
wk057 Looks fine. The first part of Trip B was the same as Since Last Charge, then Trip B was reset.�
Dec 30, 2014
Bighorn Now I'm with you--was only seeing the P85 page, not the tabs at the bottom for P85D or Calculations.�
Dec 30, 2014
scottf200 Mentioned in the added Q&A
Answers to Common Questions
Q: Which drive unit is able to sleep, front or rear?
With the P85D we put the large, rear, drive unit to sleep while cruising. We choose to sleep the rear unit since the new generation small front drive unit is actually more efficient at converting battery DC electricity into mechanical shaft power. So we benefit from using the small, front drive unit more of the time when it can provide all of the torque requested. In the 85D both drive units are the same and we can sleep either unit, front or rear to best optimize efficiency.
Q: Are standard or cyclone 19" wheels more efficient?
Cyclone 19" wheels are slightly more efficient than the standard, base, 19" wheels. This efficiency gain comes from an aerodynamic improvement of the wheel itself and the 19" tire effects are separate. The aerodynamic benefits are most pronounced at higher speeds so you will see the biggest gains at 65mph or 75mph cruising. For instance, the 19" Cyclone wheel gives roughly 2% more range than the 19" standard wheel at 65mph. The difference will be less than 1% in city driving however.
Q: What are the best 19" tires?
The Michelin Primacy 19" tires give roughly 3% more range than the Goodyear 19" tires at 65 mph. The difference is greater, up to perhaps 5% difference in range, in slower city driving. We do not have any suitable production tires better than the Michelin Primacy to offer yet but are constantly evaluating and testing new options. Many tires claim larger improvements than we actually see in real world testing so beware of aftermarket label specifications. Tires are an area of increasing focus for us as a company.
Q: Do wheel mass differences contribute to range differences?
The mass differences between the various wheel and tire options are quite small. The variance in range is created from rolling and aerodynamic differences between them. (see answers above)
Q: Will we offer a dedicated Aero Wheel design again?
The customer take rate on our previous Aero Wheel design was so low that we could not justify continuing the production and supply chain complexity of it. In general we are working to simplify the complexity of options available and eliminate those where we see fewer than 1/20 people choosing an option. In addition, the newer Cyclone wheel captures much of the aerodynamic benefit of that the dedicated Aero Wheel design did over the standard, base 19" wheel.�
Dec 31, 2014
AnxietyRanger Very good blog update from Tesla, thank you.
And wk057, thank you for the data and keep up the good work!�
Dec 31, 2014
wk057 Still working on video editing for my videos. Syncing up the dash cam videos with the GoPro videos is turning out to be a huge pain, so, might skip that part...
I managed to pull the full dash of each car up using perspective correction from the GoPro videos with decent results, and those are actually easy to sync to within a frame or two.�
Jan 1, 2015
Chris_WDO wk057, thank you very much for your time and effort you put into this, I really appreaciate that!�
Jan 1, 2015
jerry33 I second that. Every additional bit that we know about the car makes us more effective drivers.�
Jan 1, 2015
kennybobby Is there an app on the center console to indicate what size tires and wheels are on the vehicle? How does the vehicle measure or calculate the vehicle speed or distance travelled--does it use the ABS wheel speed sensors, or use motor rpm and gearbox ratio, etc.?
The reason i bring this up is that your P85D rear tires are larger than the 85 standard. Maybe this contributes somewhat to the issue. What is hard to reconcile is how your odometer reads MORE miles than the yellow car--if they are counting wheel revolutions then your car should have shown LESS. And, on the same cruise settings your car should have been overtaking her car.
In the patent for the AWD torque control it is interesting that they don't use the term "measure" for vehicle speed, but rather it is always called 'calculated' speed. Link to patent here: Dual Motor (and Triple) Torque Control for Maximum Efficiency
diam config width prof diam. ft/revrevs/mile delta %
19 winter 245 45 27.68 7.25 728.6 0.00
21 winter 245 35 27.75 7.27 726.7 -0.26
21 wk057 D f 245 35 27.75 7.27 726.7 -0.26
21 wk057 D r 265 35 28.30 7.41 712.6 -2.20
Don't know why it loses the spacing...�
Jan 1, 2015
scottf200 Used courier and _�
Jan 1, 2015
wk057 This forum does support�
Jan 4, 2015
xy46 To wk057 - thanks for taking the time to do this. It is really appreciated!�
Jan 4, 2015
wk057 So, got tied up with other things this weekend. I do think I found my issue with my dash cam footage sync... turns out that the cams change frame rates in different modes, even though the video length is the same. So, transcoding those with lower framerates up to a higher frame rate (duplicating frames) so that they fit in my project...
Hopefully have at least leg 1 done today...�
Jan 4, 2015
wk057 OK, finally done editing and syncing on video for the first leg. I may skip the second leg... I think the first one plus the numeric data is plenty of data, honestly.
Rendering a 5x speed time lapse of leg 1 now (~12 minute video). Probably take a couple of hours.
Edit: Here is a snapshot from somewhere in the first couple of minutes:
I think it came out pretty good considering the view of the dash from the GoPro cameras is actually like this:
No, I haven't had time to fully install my dash cam yet�
Jan 4, 2015
wk057 OK, video is up for leg 1.
Edit: Note to mods: Not being able to add this to the first post is not fun.�
Jan 4, 2015
AnxietyRanger Huge, absolutely massive, mind-alteringly big thanks to wk057 for the effort.
This sets the golden standard for forum participation for some time to come.�
Jan 4, 2015
FredTMC So, where will the wh/mi come out on the D once the ~10% improvement is factored in for the "normal" mode?
Looks like the P85 was around 319 wh/mi for the trip...�
Jan 4, 2015
Footbag @wk057 superb job on the video.�
Jan 4, 2015
wk057 If it is a 10% improvement it would land it at 322 Wh/mi. The P85 ended leg two of the trip at 310 Wh/mi and the P85D at 358 Wh/mi.
Thanks for the encouragement everyone.�
Jan 4, 2015
MartinAustin Indeed!�
Jan 5, 2015
svp6 Awesome - great work. So there is hope for the P85D range. I hope they push the update soon so we get some relief with winter driving.�
Jan 5, 2015
lolachampcar I picked up a loaner P85D and ran several normal trips for me where I knew my P+ consumption within a few percent. WK's numbers match mine almost exactly which is a little scary. Thanks for all the hard work..�
Jan 5, 2015
Adm Is there a significant difference in wind resistance comparing a painted car and a wrapped car? I assume the yellow car is wrapped.�
Jan 5, 2015
andrewket I'm back from my Ft. Lauderdale to Northern VA road trip in my P85D. 1,074.6 miles, 407.3 kWh, 379 avg wH/mile. 19" primacy tires, 2 adults, 2 kids, trunk packed with luggage including the foot well. Mixed driving; cruise set anywhere between 65-90, with peaks above and below depending on traffic. Range was never an issue while using the superchargers along I-95. I'll still be happier when the new software is available that supports idling the rear engine, but my range concerns were unwarranted. The only difference was a bit more time spent charging and I was unable to skip any of the SCs.�
Jan 5, 2015
Jallum.pa.us Is that the blackvue 650? I just installed mine (in the front) yesterday. If you pull the door sill trim on the passenger side, you'll find many good sources of constant 12v.�
Jan 5, 2015
wk057 I didn't notice any difference since her car was wrapped. If anything I'd think it'd be a detriment, but not a significant one.
Yes it is. I have the 550 in the P85 (and left one in my traded P85) all nicely installed. I ended up running straight to the fuse box though. I may look around for some constant 12V inside the car to tap this time instead.�
Jan 5, 2015
yoyo There is still that unused connector inside the microphone panel directly above the rear view mirror. It is very convenient and is constant 12v It is there for my P85D at least�
Jan 5, 2015
wk057 I'll have to check that out... I was under the impression there was no longer a constant 12V there on newer VINs.�
Jan 5, 2015
dennis Wow, what a great job! Obviously a huge amount of work on your part. Given than, do you have any inclination to rerun at least a part of the comparison when the new P85D firmware is delivered later this month (we hope)?�
Jan 5, 2015
ruby110 WK057, Bravo! Thanks to you both for all that work.�
Jan 5, 2015
wk057 I do want to do the same run whenever the new firmware is out for sure. Since the place we went to is a pretty tasty Japanese restaurant it shouldn't be hard to convince my fiance to do a second run later.�
Jan 5, 2015
lolachampcar ill pitch in to buy dinner�
Jan 5, 2015
Gizmotoy It got added back in at some point a few months before the autopilot stuff started rolling out.�
Jan 5, 2015
maddog1762 Wow, hard to compete with this kind of post, Awesome and thanks for sharing�
Jan 5, 2015
maddog1762
You have pics of your mounting setup?
Thanks�
Jan 5, 2015
Nickjhowe @WK057 Excellent work!! Thanks much for putting the effort in.�
Jan 5, 2015
wk057 I plan on doing a thread on the install of the 650 in the P85D once I get time.�
Jan 5, 2015
andrewket I had a 400 in my P85+. I just ordered a 650 for the D, but it appears to be on back order at blackboxmycar.com.�
Jan 5, 2015
nwdiver WOW... had no idea the fog lights used that much energy... :tongue:�
Jan 6, 2015
Jallum.pa.us This was the first thing that I looked at. There's definitely a three wire unused connector, but I was unable to sense more than 10.5v on any combination of the wires and none were able to drive the 650. My guess is that they're for a sensor / mic / etc. that we don't have.�
Jan 6, 2015
Hasse Wk057: Great effort with this video! Now, another question: How often do you find the time to read private messages here on TMC?�
Jan 6, 2015
yoyo On mine?the two outer pins give you between 13.5 and 14.3v. The one with brown strip is positive and the black is ground. The green wire gives you under 4v.
I already installed DR550 front and rear and they work in all modes including parking
It is p85d with vin in 648xx
�
Jan 6, 2015
andrewket Did you find the part number for the corresponding plug? I'm waiting for a 650; might as well order the parts needed for the install.�
Jan 6, 2015
yoyo i did not order any part. Just followed the method described in that dashcam thread- cut off extra wires, strip the end, pop open the connector clip, and stick the two wires from the back of the connector and wiggle them into the pin slots, align the wires with existing wiring then close the clip - it will keep them tight and not easily pulled out. I then used electrical tape to wrap the connector just in case.
i did not take pictures. But will try tomorrow�
Jan 6, 2015
andrewket Interesting. On my previous S I used headers and soldered the wire. I don't think the plug had a clip, but I could be wrong. It was almost two years ago.�
Jan 6, 2015
Jallum.pa.us I went back out into the cold and snow just now, multimeter in hand to recheck this. Lo, and behold... 14.9v (while charging) on the two outer pins. I'm happy to be wrong!�
Jan 6, 2015
cynix Does the voltage drop slightly when the car is parked/turned off but not charging? I plan to get a Cowon AW2, which uses the voltage drop to detect when to enter "parking mode".�
Jan 6, 2015
andrewket Replying to my own post (edit wasn't working for some reason). My last sentence wasn't 100% accurate. I was able to drive from Glen Allen (Richmond) to home, skipping Potomac mall. I don't recall what my remaining energy was when I arrived home, and if I would have been able to make it to the Delaware SC without stopping at Potomac. I'm guessing probably not.
- - - Updated - - -
This is exactly why I decided against the AW2. There is no alternator to stop and therefore no corresponding voltage drop. I don't think the AW2 will be able to automatically engage parking mode on a model S. The blackvue uses GPS and/or the accelerometer.�
Jan 6, 2015
wk057
The Model S DC-DC can engage/disengage at any time while the car sits. It generally does so to boost up the 12V battery or while the battery heater is needed or some other idle load from the main pack. So using voltage drop to go to parking mode will not work.
@andrewket - I was able to make Newark to Glen Allen on my southbound trip, taking it pretty easy, limited HVAC, 100% charge in Newark, arrived with 19 miles to spare. If I had driven like I would normally had driven my P85 (cruise at 78 through Fredricksburg area and other 65/70 MPH zone, 68 elsewhere) I most certainly would not have made it. Instead I kept to right lane driving. That ~15% efficiency loss does matter, unfortunately.
I do try to avoid the Woodbridge, VA supercharger. It's kind of a terrible spot, IMO. Traffic to get to and from the charger is ridiculous during a large block of times during even a normal week. It has taken me 20 minutes to get between that charger and 95... worst of any other I've been to.�
Jan 6, 2015
Nickjhowe I spoke to the plug manufacturer and there is no matching part. The plug is designed to plug into a device, and is not a simple make/female connector.�
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