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EPA Range for 70D 240 miles - does it make sense?

Discussion in 'Model S' started by David_Cary, Apr 8, 2015.

  1. David_Cary

    David_Cary Member

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    If you do the math 70/85 * 270 (range for 85D) = 222.

    Now we all know that the 60 was more efficient and did better than 60/85 * 265 = 187. At 208 miles it was 21 better than "predicted" and now the S70D is 18 better than predicted.

    None of that made any sense to me then and it still doesn't. A few hundred pounds isn't going to make that much of a difference in highway range. The problem is the EPA range is a blended city/highway range but that still didn't make sense. On the Tesla website, the difference in highway range was more than the difference in EPA for a 60 and a 85 which makes sense. But still, the difference was not as great as you think.

    Unfortunately, all of this hand wringing is important because a lot of us are considering the S70D because the value proposition is so much better than before. But is the real highway difference only 30 miles or is is more like 50 since the EPA represents a blended city/highway number

    For me, I have a 85D that was confirmed last night (love the timing). I'm tall and I've never had a power liftgate before. So $500 change fee and I can save $1750 on tech and $1000 on pano roof. And then maybe $10k on the battery. Decisions decisions.

    So I need someone to drive a 70D on 3000 mile old tires (19s) at 70 mph and see how far you get. And I need that in the next week or so. TIA:cool:

    Would be helpful if Tesla could update the FAQ on range with 70D but I'm not sure I'd believe that anyway.
     
  2. Saghost

    Saghost Active Member

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    The efficiency edge of the S60 does appear to be larger than simple weight should produce. At the same time, when I started a thread to talk about it, the user feedback came back that the benefit was real, not just something odd the EPA did. I would expect the S70D to retain most of that edge - which would seem to make it a better choice unless you really need the other 20-30 miles.
    Walter
     
  3. lphe

    lphe Member

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    Perhaps the smaller motors in the 70D use less energy. In the S85, the useable energy from the battery is about 75 kWh. I wonder what the useable energy from the 70D will be? Tesla should update the range calculator at their web site to include the 70D so we can compare more than just the EPA range with the other models.
     
  4. lphe

    lphe Member

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    Tesla's Blog at their website in the news releases states the range is 240 miles highway at 65 mph. In the design studio, it states 240 miles range EPA. Are both ranges 240 miles, or is one in error?
     
  5. arijaycomet

    arijaycomet Member

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    LOL... this quote right here! :p too funny...

    As a comparison to your math.. here is what I did earlier today...
    208 miles on 60 kWh (60) = 3.467 miles per kWh
    265 miles on 85 kWh (85) = 3.118 miles per kWh
    270 miles on 85 kWh (85D) = 3.176 miles per kWh
    and the new layout:
    240 miles on 70 kWh (70D) = 3.429 miles per kWh

    What seems to make sense is they aren't all that far apart. Weight savings 70 vs 85 is probably still rather significant. And when you look at the old 85 vs 85D you saw a small benefit from the AWD. So it would make sense that the added batteries (60 vs 70) would be MOSTLY negated by the added benefit of the AWD. Based on this the math seems "legit" to me, so to speak of.... but then again we all know how inaccurate those EPA figures are to begin with.

    I'd probably assume the 70 vs 85 would offer weight savings, so it should be better miles per watt-hour.... so 70D vs 85D, you'd expect better on the 70... and as per above, there is about a 10% benefit. So really, forget about the actual RANGE the car gets, and look more so at the cost per mile here. We only pay $0.12 per kWh net in Ohio .... so that savings isn't huge. But in places where electricity costs double that, the 70D is actually more "fuel efficient" (cost effective) over the heavier 85D.... those extra few miles of range be damned. :)
     
  6. apacheguy

    apacheguy Sig 255, VIN 320

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    I know this is off track here, but gotta say it. For those that want to jump ship and go for the 70 instead of the 85 just be sure you're considering impacts on degradation and SpC rate and taper. If you don't know what I mean by that, I might suggest you do a little research before making a hasty decision.
     
  7. rammer91

    rammer91 Member

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    Apache: Thanks for bringing this up. I am one of those who don't know what you mean about "impacts on degradation and SpC rate and taper." I also tried googling those terms to no avail. Do you have any handy information or links from with which I could start to educate myself? Thanks in advance!
     
  8. Saghost

    Saghost Active Member

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    I'm really not sure what he means about degradation, unless its the general EV point that if you buy a car that just barely meets your needs when new, in a few years it might just barely not meet your needs instead.

    For Supercharger taper, the 60 ends up being a lot slower than the 85 overall, little more than half the speed in km of rated range per unit time in some parts of the curve. I don't think we have any idea what the 70D will be like, though I'd assume it won't be as good as the newest 85 packs are.

    If you look at the video here at the bottom of the page, Bjorn has done a fairly good job of comparing the CHAdeMO vs a 60 vs an 85 in time lapse...
     
  9. cpa

    cpa Member

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    I think what Apache is referring to is that all batteries degrade from day one. A general consensus among the smarter folks here is that the 85 degrades about 6% the first year and then about 1% in each successive year. So, the putative 240-mile range at purchase will drop by about 13 miles after one year of ownership and about two miles per year thereafter.

    The taper at Superchargers starts sooner on smaller batteries. If an 85kWh battery and a 70kWh battery were both at 30 rated miles and were going to charge to 225 rated miles, the 85kWh battery would finish before the 70 because the taper kicks in later.

    I am sure Apache will clarify and correct my words!
     
  10. LargeHamCollider

    LargeHamCollider Battery cells != scalable

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    #10 LargeHamCollider, Apr 8, 2015
    Last edited: Apr 8, 2015
    The rated range of the new 70D gives is the only real (if a bit shaky) data we have to determine whether or not the new 70D uses a new cell chemistry.

    If it does not use a new cell chemistry then it's efficiency should be 10/25ths of the way between the efficiency of the old 60 and the S85 plus (270/265 -1)% to account for dual drive or 3.390 miles/kWh.

    If it *does* use a new cell chemistry then it's efficiency should be about equal to the efficiency of the old 60 plus (270/265 -1)% to account for dual drive or 3.532 miles/kWh. Given that actual efficiency is 3.429miles/kWh I think this gives some evidence in favor of the "old chemistry hypothesis".

    this assumes new cells are roughly the same mass as the old cells.
     
  11. arijaycomet

    arijaycomet Member

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    I'm not sure I agree with this math entirely. See, we know the 85 vs 85D would have the same weight battery, but the addition of an added motor. In that specific case, the gains were the 265/270 you mention, which is about 1.8% more range benefit even with the added heft of a second motor. In the case of the 70D there is a weight savings versus the 85D, but a weight addition versus the 60-RWD. So it would be purely speculation, since the weight isn't going to be entirely linear to the battery alone (the base of the car still weights the same just the batteries are different).

    Take a look at gas cars that have the same motor in them in much larger cars. For example, the 2.0L turbo motor that Volkswagen offers is the same motor in the GTI/Jetta as other iterations (such as the Tiguan SUV). But the SUV is far less economic based on the size, shape, weight, etc. Which is why I still think it's too difficult to scientifically estimate here these figures... its fun, but I don't think we'll ever be accurate enough because we cannot determine precisely how much gain/loss going from 70 vs 85 kWh batteries (weight) would actually affect miles/kwh ...
     
  12. evmile

    evmile Member

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    I think two things changed:

    1) 60 to 70 kWh
    2) single to dual motors.

    The single to two motors can be the real source of the improvement since it is like having a two speed transmission vs. a single speed. The front motor is geared for high speed and the rear motor is geared for low speed. They can be used as such so each motor is running at it's most efficient speed and the other motor is shut off.
     
  13. LargeHamCollider

    LargeHamCollider Battery cells != scalable

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    Yes, I stated that the data was shaky, also I made a math error that messed up the conclusion, original post has been edited.
     
  14. Rama

    Rama Member

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    I'll be one of the first people to take delivery of a 70D (late May). I'll get right on it. :smile:
     
  15. David_Cary

    David_Cary Member

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    #15 David_Cary, Apr 8, 2015
    Last edited: Apr 8, 2015
    So highway range is actually close to 40 miles difference (insideevs.com). They have highway at 246 and 285.

    The lease price is about $180 difference between the 70D and 85D. When the range difference might mean 20 minutes extra at a supercharger every 3 months, that is a pretty expensive 20 minutes ($540).

    Time to get back to the maps and plug in some degradation math.

    Did anyone else see the comment -"Voluntarily reduced the range to 240" - looking at the numbers it should be 244 or 245
     
  16. apacheguy

    apacheguy Sig 255, VIN 320

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    Degradation: A larger battery undergoes fewer cycles. Period. Hence, the load on individual cells is lessened and the pack generally has a longer lifespan and suffers from less degradation.

    SpC taper: 60 owners often complained about this. While on a road trip, expect to spend longer at a SpC because a smaller battery simply cannot be charged as fast as a larger one. Tesla's taper already kicks in well before 50%, but at least in my 85 kWh, charging up to 50% is sometimes a good option before I get too far into the taper and it becomes less efficient. 60s (or maybe 70s) wouldn't be able to do this because 50% isn't sufficient range in most cases.
     
  17. Mnlevin

    Mnlevin Member

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    DEGRADATION??? My MS 60 is 2 years old with 43k miles and has only lost 3 miles of range at 90%. The think I will agree is that my P85 does charge to what I need to get to the next SC quicker because of the extra capacity. But all that said, I don't believe that a 70D will be more efficient and get more range than a 2 WD MS 60. I am sad to is see that TESLA has raised the entry bar. Some people who may have stretched to get into a MS at around $70k are now faced with a minimum of around $80k. My base MS 60 priced like a 70D is almost 15k less with more equipment.
     
  18. svp6

    svp6 Member

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    This is nice if you live in a climate that is warm most of the year. If you have winters like Minnesota, those 15 KWh will make a big difference if you decide to go for a road trip. Be aware that the Tesla guestimator in range you can drive at 0F is overly optimistic. I drove the P85D for 3000 miles over last 3 months and my average is 477 Wh/mi. If you consider 75 KW usable part of the 85 battery pack, range comes to 157 miles...... I did several trips to Minneapolis (~190 miles total) in 0-10 F cold, but I had to go less than 65 mph to make it (barely).

    Bottom line: 240 miles is theoretical, and in real life situations you will get significantly less. If you have lots of superchargers, it does not matter. If you don't, I would suggest sticking with 85 kW.
     
  19. Cyclone

    Cyclone Active Member

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    But so are the 253, 265, and 270 miles rating. To me, that is still an apples-to-apples comparison. I personally am changing from an 85D to a 70D. I plan on occasional road trips and outside of planning then, a 60 would have served me fine. But once you count the supercharger entry fee and the lack of a dual motor, I was just going to bite the bullet and buy a 85D in a few more months after saving up the extra cost. I expect real world use of the 70D to be around 30 miles fewer than the 85D. Since I rarely plan to stretch to that limit where 30 miles will make a meaningful difference, I plan to save the funds and just plan accordingly when the time comes. If this means I need to stay longer at a supercharger or hit up plug share on road trips, so be it. If I decide to skip the power liftgate, then I will also forgo the alcantara and end up spending significantly less than my planned 85D. Now, if I made enough per year that it wouldn't make a dent in my budget, then sure a P85D would be great. But the 70D is already just over 2x any previous purchase and significantly over the normal car budget (if financed, a 85D will actually be more than my current car payment, mortgage, and second mortgage combined). As Mnlevin described, this is the perfect Tesla for me!
     
  20. saz25

    saz25 Member

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    Can we "infer", that if Tesla just upgraded the S60 to create a S70, that perhaps we may see an S100 sooner than later?
     

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