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Model S Wh/mi vs Leaf mi/kWh

Discussion in 'Tesla Motors' started by PokerBroker, Apr 5, 2015.

  1. PokerBroker

    PokerBroker Member

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    Being both a Tesla owner and more recently (yesterday!) a Leaf owner I am really liking the Leaf's energy efficiency unit better than Tesla's. I understand that it really is two ways to say the same thing but 3.5mi/kWh is a much more intuitive unit for me than 300wh/mi.

    Anyone else with this experience or a different one?
     
  2. efusco

    efusco Moderator - Model S & X forums

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    In Canada (and likely elsewhere) with gas vehicles they use gal/100km vs mi/gal in the US. I, like you, would prefer they stick with one standard for the industry. Either way, at least it's pretty easy to translate one to the other.
     
  3. cantdecide

    cantdecide Member

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    I think Tesla has it right, Nissan has it wrong.
    If I get 20mi/kWh going to work and 3mi/kWh going home, what is my average? A bit less than 6. Tough calculation.
    If I get 4.2mi/kWh and I need to drive 10 miles, how many kWh do I need?
    These questions are trivial to mentally calculate in kWh/mi but tough in mi/kWh.

    How many mi/kWh less do I get at 60mph when I add a roof rack? Answer: depends on hills and if you have the car heater on.
    How many more wh/mi do I use at 60mph when I add a roof rack? Much less dependent on those other numbers.

    Perhaps 0.3 kWh/mi would be better for you than what/mi?

    Similar problems happen with mpg compared to liters per 100km that non Americans use...
    People think that 8mpg and 12mpg are not much different e.g. for an SUV or rv, while people think that 50mpg Prius and 100mpg car are more different... While in reality when driving the same distance the energy used 8 to 12 is massively bigger difference than 50 to 100
     
  4. dirkhh

    dirkhh Middle-aged Member

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    It's all what you are used to.
    I'd argue that it is much more intuitive to consider how much you consume given a distance as we almost always have a sense of the distance we need to go and now can easily get an idea how much energy this takes.
    In real life it seems to me it's far less common to have a given amount of energy and to wonder how one can go with that.
    So I find mpg not really useful, and I find the miles per kWh in my Leaf not really all that insightful.

    PokerBroker - what's the real life scenario where you ask yourself how many miles you can go on a kWh? The only moment where I would consider this useful is when I'm looking at my total max range - and that's already given to me in miles by either car...
     
  5. SabrToothSqrl

    SabrToothSqrl Active Member

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    I'd prefer the /kWh as I could figure out cost per mile easier, but at least we all can agree on what a kWh is.... vs a mile/kilometer/yard/mm/etc.

    I really wish any non-metric system would just go away already.
     
  6. RomeoT

    RomeoT Member

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    I like Mi/kWh better. My leaf gets more than 5 miles per kWh, way better than Tesla S60.
     
  7. CmdrThor

    CmdrThor Member

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    I hadn't even thought of this, but it makes so much sense after you pointed it out .. Now wishing my LEAF reported watts/mi.
     
  8. dirkhh

    dirkhh Middle-aged Member

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    Many of us do. It's especially annoying if you have both a Leaf and a Tesla...
     
  9. jerry33

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

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    My S85 has averaged 4 miles per kWh (250 Wh/mi) over 42,000 miles. I'm sure an S60 could do much better.
     
  10. dirkhh

    dirkhh Middle-aged Member

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    Only if driven a constant 45mph in warm weather in a completely flat environment.
    Your numbers are unbelievable, jerry33... and complete outliers :)
     
  11. ecarfan

    ecarfan Well-Known Member

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    250 Wh/mi average is extraordinary. You are in Texas so I assume primarily flat roads, but still...how did you do that?
     
  12. jerry33

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

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    Mostly it's practice, although I don't try as hard with the Tesla as I did with the Prius (last full year averaged a bit over 69 mpg). Avoid acceleration uphills, accelerate downhills, not too many rocket launches or rapid stops, and keeping some air in the tires. If you have a regular commute you can try different approaches and see which one is best. Also sometimes you can alter the route each direction to reduce the "bad direction's" energy usage.
    About 50% is long distance highway.
     
  13. cantdecide

    cantdecide Member

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    How fast do you drive on the highway? What is your when/m on highway versus commute? I had assumed you were just using the car for commuting.

    For me... I get 240 on a decent day, and 220 on a great day... For my commute which is 30 miles round trip, hilly, but mostly 35mph speed limit. For freeway I'm over 300... Netting 290 total. I had assumed your usage was similar to my commute?
     
  14. Twiglett

    Twiglett Single pedal driver

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    Its funny - when I got my Leaf I drove it in Eco mode, followed all the coaching it does to help you drive economically - what a joke.
    The difference in cost, watts per mile or miles per kW is laughably small, I gave up.
    Haven't been in Eco mode in 8 months and drive it like I stole it.
    Waay more fun and the cost to the pocketbook can't be more than $10-20 over the 12000 miles in this year - well worth it.
    Only range gauge I use is the battery percentage.
    But yes - miles per KW is a pain to figure out - I just switch it to WPM in my head now.
     
  15. purplewalt

    purplewalt Active Member

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    When Elon visited Austin earlier this year, several North Texas Tesla owners stopped @ Waco CSB Supercharger and visited while our cars charged.
    We had all range-charged earlier in the day, driven to Austin and returned.
    Waco to Austin is 100 miles, so it was a 200 mile RT.

    Most of us arrived back at Waco with 30 miles or so of remaining Range.
    Everyone except Jerry.
    I think he still had something like 80 miles of Range when he arrived @ Waco on the return leg from Austin.
    And he had been giving demos and test rides to interested people while he was in Austin.

    I dunno.
    Maybe he already has a 100 or 105 battery pack in his car?
    Or maybe he knows the secret password to unlock new tricks in the battery.

    AFAIK, he is THE Master of getting the most mileage out of a single charge.
     
  16. jerry33

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

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    42K miles in 24 months would be one heck of a commute.

    My commute is a bit longer than yours--just over 50 miles round trip and it seems as if there are plenty of hills. The speed limits on the commute are 40, 45, and 60. Between 210 and 240 is about right unless the weather is bad, but also it depends whether I make any side trips or not. I suspect the extra 20 miles makes up the difference. Highway varies between 230 and 260, mostly depending upon wind direction. Speed varies but I try to keep it around 60 to 65. Actually, I don't look at the speedo that much, I look at the power metre a lot more. Steady power is more important than steady speed. If the hills are just right, it's possible to do 70-75 and get 240 to 250 kWh/mi. But mostly it's just practice--a lot of practice.
     

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