TMC is an independent, primarily volunteer organization that relies on ad revenue to cover its operating costs. Please consider whitelisting TMC on your ad blocker and becoming a Supporting Member. For more info: Support TMC
Start a Discussionhttps://teslamotorsclub.com/tmc/tags/

Telsa EV efficiency vs Bolt

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

  1. insaneoctane

    insaneoctane Member

    Joined:
    Apr 6, 2016
    Messages:
    559
    Location:
    Southern California
    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?
     
    • Informative x 1
  2. shrspeedblade

    shrspeedblade Member

    Joined:
    Sep 29, 2015
    Messages:
    485
    Location:
    CA, United States
    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. :)
     
    • Informative x 1
  3. insaneoctane

    insaneoctane Member

    Joined:
    Apr 6, 2016
    Messages:
    559
    Location:
    Southern California
    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

    Joined:
    Mar 11, 2016
    Messages:
    534
    Location:
    Toronto, Ontario, Canada
    The Tesla is more efficient on the highway or just accelerates faster? Thank you in advance.
     
  5. insaneoctane

    insaneoctane Member

    Joined:
    Apr 6, 2016
    Messages:
    559
    Location:
    Southern California
    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.
     
    • Informative x 1
  6. Jeff N

    Jeff N Active Member

    Joined:
    Oct 31, 2011
    Messages:
    1,715
    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

    Joined:
    Aug 26, 2016
    Messages:
    207
    Location:
    SF Bay Area
    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.
     
    • Informative x 2
    • Like x 2

Share This Page