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Performance and efficiency

Discussion in 'Model S' started by Rawad H., May 19, 2015.

  1. Rawad H.

    Rawad H. Member

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    Livonia mi
    So I have a couple quick questions

    1. Driving in 70 degree whether my 85 model has its acceleration restricted to half way between 160 and 320, is there a reason for this?

    2. My range no matter how efficiently I drive is not even getting close to the rated, I had a Wh/m of 302 with 55.2 KW used with 13 miles rated range left and a total of 180 miles driven. What else could I possibly do to improve this I feel like that 265 number is bogus.
     
  2. MarcG

    MarcG Active Member

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    #2 MarcG, May 19, 2015
    Last edited: May 19, 2015
    1. Your SoC (State of Charge) could be low. What was the rated range left when you saw the power restriction?

    2. What did your SoC start at? 100%? 90%? How many rated miles do you get when you charge to 100%? What was the net elevation change? Were the roads dry or wet? Need a lot more information here.

    FYI, in general to properly log a trip, I start by resetting one of the 2 trip meters, then keep track of:

    Rated miles at start
    Rated miles at end
    Distance traveled
    Time traveled
    Speed (divide total distance by total time)
    kWh used
    Wh/mi average
    Outside temp
    Climate settings
    Road conditions (wet, dry, snow..)
    Net elevation gain/loss - this makes a huge difference!

    See this Google doc for examples on tracking trips:
    P85D Uninterrupted Hwy Trip Data - Google Sheets

    One thing we can't really track very well is wind speed, which could also hugely impact range if headwinds are strong.
    You can get instantaneous wind speed and direction from an app, but averaging that over an entire trip is complicated.

    Anyway, you get the idea: lots of parameters matter and impact efficiency.
     
  3. Andyw2100

    Andyw2100 Well-Known Member

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    Are you driving a D? If so, you need to turn range mode on to maximize the efficiency gains from torque sleep.

    And everything MarcG said.
     
  4. Rawad H.

    Rawad H. Member

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    I have a 85 no D, and the driving is done with no heavy rain or cold. Charged to 80% which shows a rated range of 240 and max I can get is 190s
     
  5. MarcG

    MarcG Active Member

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    That right there is your problem. 80% of 265 (rated range for a BRAND NEW S85 with NO degradation) is 212, not 240.

    You probably have your range set to IDEAL instead of RATED. Change that setting and you'll get more realistic numbers.
     
  6. derekt75

    derekt75 Member

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    If you're getting 300 Wh/mile, then I would think you'd be getting the rated range.
    If the car says it used 55 kWh, but the range dropped from 240 to 13, it seems like something else happened to steal energy, like the car being on and in park for a while with the computers and air conditioner running.
    80% and 240 don't jive particularly well, by the way. Are you sure 55 kWh dropped it from 240 to 13?

    I don't get anywhere close to the rated range, but my car tells me I burn 400 Wh/mile (I drive above the speed limit, and I literally have a head wind in both directions of my commute every day), so I expect to be off by 30%.

    - - - Updated - - -

    Oh, I forgot IDEAL was even an option; it's such a worthless number to me.
    I'd prefer if there was a RATED and a THE_WAY_YOU_SEEM_TO_DRIVE, rather than a RATED and an IDEAL.
     
  7. brianman

    brianman Burrito Founder

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    Bingo.

    - - - Updated - - -

    You've given me an idea...

    Updated:
    Join the club, er, group:
    Projected Range Fans - Tesla Motors Club - Enthusiasts & Owners Forum
     
  8. MarcG

    MarcG Active Member

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    There's already such a figure and it's called "Projected Range", which you can see in the Consumption graph of the Energy app.

    Unfortunately, that's the only place where it lives on the car displays (VisibleTesla shows it via the Tesla API) and it only accounts for the last 30 miles (or 15, or 5 on the Energy app).
    There's no way to make it the default range mode so that you can see it in the dashboard screen, and that's been discussed at length in other threads.
     
  9. derekt75

    derekt75 Member

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    Projected range has also always been worthless to me. The last 5 miles has too much random noise (was there a little hill? did the traffic cause me to slow down for a bit?), while the last 30 miles usually includes irrelevant data (huge hill, traffic light, etc.).

    or how about this: if I know that I drive 75mph on the freeway, how about I tell the car that I drive 75 mph on the freeway, rather than having it assume I'm going to drive an unrealistic 65. just a slider somewhere in settings where I can choose my preferred highway speed to use for range calculations.
     
  10. MarcG

    MarcG Active Member

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    I found that the car actually does learn your driving speed habits over time, and you can tell by looking at the Trip section of the Energy app.
    If you mostly drive 75 mph on the highway, the car will eventually learn this and you'll see the green line (actuals) closely match the gray line (estimated) if you continue to drive at 75 mph.

    I personally noticed this when I initially started tracking my trips: the green line was constantly below the gray line, as I was driving faster than the speed limit.
    At some point, the lines matched up closely as the car was learning that I was often driving 5-10mph above the limit. One day I wanted to "hypermile" so I decided to drive the speed limit, and found the green line ended up way above the gray one.
     
  11. Joel

    Joel Active Member

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    Rawad -

    I believe others have covered it at this point, but you need to Max charge and then drive to almost empty to determine battery capacity (never drive at or below zero).

    From one Michigan Driver to another, the 265 number is bogus. Tesla plays it safe on the range. I typically get closer to 280 to 285. The last time I drove North of Traverse City from Metro Detroit (270+ Mile Trip) was 50 miles after I bought new tires. So, the below pictures are lower mileage than I typically experience due to the high rolling resistance from new tires. Here's my trip last year with brand new tires, 24K miles in ideal conditions, driving the speed limit with climate set at 68 degrees. I'm taking this trip in 3 weeks. I'll report back after I return.

    IMG_4708.jpg IMG_4799.JPG
     

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