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Telsa EV efficiency vs Bolt

Discussion in 'Model 3' started by insaneoctane, Jun 21, 2017.

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  1. insaneoctane

    insaneoctane Active Member

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    As a soon-to-be M3 new owner, I've been looking at the only other vehicle, Chevy Bolt, that I can compare to. I'm curios about the efficiency difference between the Telsa MS and Bolt as I try to extrapolate what the M3 might be. I know I could just wait until next month, but what's the fun in that?
    Specifically, numbers from the EPA...
    Code:
    Vehicle   Range    R,city    R, hwy    kWh/100 mi   kWh/100 mi,c   kWh/100 mi,h
    Bolt      238.0    256.0     220.0     28.4         26.3           30.6
    MS 60D    218.1    211.9     224.3     32.4         33.4           31.5
    Delta     9.1%     20.8%    -1.9%     -12.4%       -21.1%         -2.7%
    
    So, while I know the MS is heavier than the Bolt, it also has less frontal area and lower drag coefficient. What's the explanation for the MS's 21% lower range in the city? I don't think it's all mass. Maybe the PMAC vs Induction contribute. I'm somewhat shocked that the MS loses this particular category by so much when I would expect Tesla light years ahead of anyone else in the EV and therefore EV efficiency category. I'm curious where we think the M3 will fall in all this?
     
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  2. shrspeedblade

    shrspeedblade Member

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    The permanent magnet motor in the Bolt is slightly more efficient, it's quite a bit lighter, and it has less rolling resistance in its tires as well.

    I expect to see a slight dip in efficiency with Model 3 vs. my Volt in city driving (I'm frequently above 4 miles/1kwh), on the highway will be a whole different story. :)
     
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  3. insaneoctane

    insaneoctane Active Member

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    I am curious what the decomposition of the 21% difference in city efficiency is....
    PMAC=10% tires=5% mass=3% ???=3%
     
  4. internalaudit

    internalaudit Member

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    The Tesla is more efficient on the highway or just accelerates faster? Thank you in advance.
     
  5. insaneoctane

    insaneoctane Active Member

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    According to the database numbers, the Tesla is less efficient at both highway and city, but narrowly on highway (Bolt = 30.6, MS = 31.5) lower is better because this is kWh consumed per 100 miles. If the speed goes high enough, then the Tesla will become more efficient due to it's superior aerodynamic design and smaller frontal area. The Tesla certainly accelerates faster.
     
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  6. Jeff N

    Jeff N Active Member

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    Also, the city and even highway test cycles slow down and speed up again. I don't know, but it's possible that some of the slowdowns exceed the regen capabilities on the 'go' pedal and require use of the brake pedal during the test. Tesla, unlike most EVs, does not do any extra regen when the brake pedal is used so any braking is friction-based and that energy is lost as heat.
     
  7. somnambule

    somnambule Member

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    I would guess the major factors are
    1. The MS is designed for higher performance (acceleration). Designing for performance has an efficiency penalty even when you don't use that performance (think 8-cylinder vs. 4-cylinder ICE).
    2. The MS is ~30% heavier than the Bolt and weight plays a much bigger role in city driving as the force (and, therefore, energy) needed to accelerate the car is directly proportional to the weight.
    3. The disparity in city may also depend on how regenerative braking is used in the EPA test. If regenerative braking is not used, the MS's weight penalty will be more accentuated. Even if regenerative braking is used, the two cars have different approaches (Bolt has different degrees of regenerative braking while MS only has on or off) and I don't know if one suits the EPA test cycle better.

    Wind resistance is not a big factor at city speeds, and the aerodynamic design won't help the MS much. It's a much bigger factor at highway speeds (goes up with speed to the power 3), and the more aerodynamic design of the MS seems to give it enough of an advantage to almost offset the other factors.
     
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  8. seattlite2004

    seattlite2004 Member

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    What kind of efficiency y'all getting on your Model 3's....and Bolt's if y'all have one?
     
  9. omgwtfbyobbq

    omgwtfbyobbq Active Member

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    Does the MS have less frontal area than the Bolt? I always thought it had more, but I could be wrong.
     
  10. insaneoctane

    insaneoctane Active Member

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    #10 insaneoctane, Apr 13, 2018
    Last edited: Apr 13, 2018
    Funny, I was wondering that too. I was questioning the OP when I read it.... But then I noticed that the OP was me! It was almost a year ago, but without double checking myself, I usually verify that stuff before I post ;)

    EDIT: Couldn't help myself...

    Bolt 25.8 sqft
    Source

    MS 25.2 sqft
    Source
     
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  11. Foxhound199

    Foxhound199 Member

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    My lifetime efficiency (~1200mi) is 260w/mi. 19" wheels, and it's been cool weather in Seattle.
     
  12. SageBrush

    SageBrush 2018: Drain the Sewer

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    I'm looking forward to a head-to-head between the Bolt and the Model 3 at 75 mph
     
  13. xav-

    xav- Active Member

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    The problem with the 3 is it’s RWD and fun to drive. At every stop light you just want the floor it.. so I think u ll probably use more energy than if you get a bolt...
     
  14. seattlite2004

    seattlite2004 Member

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    For folks that have not driven the Bolt...I think they would be surprised with the 266 ft-lbs of instant torque going to the front wheels....it has about 13% less torque than the Model 3..but the Bolt does weigh a little less than the Model 3. Instant torque is very addicting in any EV.
     
  15. cmaster

    cmaster Member

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    Well, given the small amount of efficiency loss with the MS, I still prefer the MS over the Bolt because of charging infrastructure and more cargo room!
     
  16. jerry33

    jerry33 S85 - VIN:P05130 - 3/2/13

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    I'd go for the difference in tires, and perhaps tire pressure. Since the report doesn't say what tires and what pressures each run at, that could account for the entire discrepancy.
     
  17. SageBrush

    SageBrush 2018: Drain the Sewer

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    Differences in CdA are not important in city driving; mass matters, albeit less so in an EV than an ICE due to regen braking.
     
  18. jsmay311

    jsmay311 Member

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    I'm surprised we haven't seen any controlled head-to-head tests like this from the major pro car reviewers.

    I'd also be very interested in a carefully measured comparison of vampire drains.
     
  19. novox77

    novox77 1.21 Gigawatts

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    I'm easily crushing 4mi/kWh (250Wh/mi) with the Model 3 (18" Aeros). I posted last week the results of a round trip to work where most of the drive was EAP. The car was getting under 200Wh/mi (5mi per kWh). My average drives around town generally land me between 200 and 220 Wh/mi, where there are a lot more hills and I'm pushing the car a lot more for fun.

    EPA numbers are way off for Model 3. I suspect anyone with the 18" Aeros are going to beat the EPA numbers.
     
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