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Higher than estimated range with city-only driving?

Discussion in 'Model S' started by buckerine, Jun 9, 2016.

  1. buckerine

    buckerine Member

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    Stupid question time (but humor me): if I typically drive city streets with the occasional 10 minutes of interstate driving thrown in, I should theoretically get much better range than EPA estimates, correct?
     
  2. Brass Guy

    Brass Guy Member

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    Probably not. If by "city streets" you mean lots of stop-and-go, then it's doubtful you'll surpass EPA range. Definitely not with climate control on.
    If you mean rural streets off interstates - not too much stop-and-go, speeds in the 30-50mph range - then yes you'll beat the EPA rated range. That's the majority of my driving and I beat the EPA rage this time of year, with climate control off.
     
    • Helpful x 1
  3. chillaban

    chillaban Member

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    The biggest problem here is that starting and stopping use more energy, even with regen (since you're making two trips through the battery and generating is inherently slightly less efficient than motoring). If your city streets are the kind where you can just set cruise control at 45 or 50 and go for minutes without changing your speed…. then you might indeed get better than EPA estimates. But throw some traffic lights or traffic in there, and you'll quickly find yourself losing range as quickly or more quickly than on the highway.


    The smaller problem, depending on the weather, is that constant loads like operating the heat or AC will disproportionately increase in consumption at slower speeds…
     
  4. eloder

    eloder Member

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    It's true in non-Tesla EVs (city driving can increase my Leaf's range about 25-35% above EPA), but I think the heavy weight of the Model S, and it's great aerodynamic profile, don't allow such huge gains relative to highway driving from what I've heard. However constant lower speeds can definitely give big EPA gains, as evidenced by the world record Model S drive on a single charge being very high above EPA.
     
  5. CmdrThor

    CmdrThor Member

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    I get pretty awful range on my 8 mile each way commute where I usually don't exceed 45mph. There's a lot of traffic and hills, it is usually a 25-30 minute trip. I have a Model X on which EPA rated Wh/mi is about 333. I use climate control liberally and often get >400 Wh/mi. Doesn't bother me though as I charge at work.
     
  6. mshuang

    mshuang Member

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    EPA rated Wh/mi is 237.5 (for a 85kWh battery). I typically see my Wh/mi usage around 340 or so at highway speeds. The only times I've ever gotten close to the EPA is with Autopilot on in stop and go on the highway (where due to congestion, the speed is around 20 mph). I've seen a negative Wh/mi average before on a mostly regenerative downhill.
     
  7. CmdrThor

    CmdrThor Member

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    That doesn't sound right. Isn't it closer to 300 Wh/mi? Perhaps slightly lower for dual motors.
     
  8. mshuang

    mshuang Member

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    Yes, you're right. I have no idea how they got 237.5. The best my math could do was this:

    single motor 85 kWh / 265 miles = 320 Wh/mile
    dual motor 85 kWh / 270 miles = 315 Wh/mile
    performance dual 85 kWh / 253 miles = 335 Wh / mile
     
  9. rickrickrick

    rickrickrick Member

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    One of my first observations when I made the switch from the Leaf to the Tesla was that I really didn't see any energy efficiency differences between city and highway driving. This was definitely not the case in the Leaf so I was tickled when I made the realization. My tracking data shows a decrease in energy efficiency as the temperature drops but no recognizable change as I increase the ratio of highway to city driving.

    Some context for my reply:

    - I am a "numbers guy" so I track my weekly energy consumption and mileage in a spreadsheet. I've never reset my Trip B indicator but I reset my trip A indicator every Sunday night.
    - I am NOT a speed demon. On highways I am more likely to get passed than to do the passing.
    - We live in the Philly suburbs with rolling hills in almost any direction we drive.
     
  10. SageBrush

    SageBrush Active Member

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    #10 SageBrush, Jun 9, 2016
    Last edited: Jun 9, 2016
    Cities are not created alike
    Drivers are not created alike
    Trips are not all the same

    YMMV

    I am a fuel thrifty driver, and in Albuquerque I would average over 70 mpg in our Prius outside of winter weather. That works out to ~ 175 - 200 Wh/mile. I bet it would be at least double in Boston.
     
  11. rickrickrick

    rickrickrick Member

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    We just returned from a road trip to Orlando, I averaged 299 Wh/mile on the trip down and 295 Wh/mile on the return home to PA. My overall average for the past six months is 299 Wh/mile (mostly "city" driving mixed with occasional weekend trips).
     

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