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How to Read the Energy Display

Discussion in 'Texas' started by gillben, Mar 10, 2015.

  1. gillben

    gillben Member

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    I am a non-tech, old man who does not understand how to read//understand the energy display. anyone know of a site for a tutorial.
     
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  2. tomas

    tomas Traded in 9 rep bars for M3, used to be somebody!

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    I do not know of a tutorial. There are two pages on energy display.

    Main one graphs energy consumption over the last 5, 15, or 30 miles. You can select which. It also shows a projected remaining range, which is either computed based on average of last 4, 15, or 30 miles.... or "instantaneously" based upon your consumption at the moment. That is also selectable.

    On this graph, you will see usage (expressed in watt hours per mile) increase when you are accelerating, going uphill, going into the wind, or driving fast. You will see it decrease when you are coasting, going downhill, regenerating (braking), or going at a slow, steady speed. There are two horizontal lines going across the graph. The dotted one is your average over the 5, 15, or 30 miles. The solid one near 300 watt hours per mile is "par". In other words, if you were to average that level, you would achieve exactly your rated miles.

    The trip display only operates if you are using navigation to direct you to a location. The trip energy display tracks number of miles to your destination, and shows projected remaining range at end of trip. It tracks your use along the way, and modifies the remaining range based on your actual usage.
     
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  3. gillben

    gillben Member

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    Very helpful....thanks.
     
  4. tomas

    tomas Traded in 9 rep bars for M3, used to be somebody!

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    Sure, feel free to private message me if you have follow up questions.
     
  5. ldgrmnmc

    ldgrmnmc Member

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    What is "Instant Range" versus "Average Range"?? thanks
     
  6. L.Robinson

    L.Robinson Member

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    If you go from tomas' explanation above it is the range you have left given your energy usage at the moment you check it, as during the launch you're in, or the the averaged watts per mile used over the last 5, 15, or 30 miles as you select it and the energy remaining in the battery
     
  7. chris5639

    chris5639 Member

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    Because the range is affected by many factors like speed, wind resistance, temperature, the use of heat, A/C, incline of the road, etc. the range displayed is only a best estimate based on past experience. It assumes that what was is what will be. So you get to choose whether the estimate is based on how much of the past data is used for the estimate. But you can imagine that you can be driving along a flat road and then begin a climb over a mountain pass, your estimated range will start to drop at a dramatic rate. Likewise, when you begin your decent on the other end, the estimate will be more pessimistic until enough new data is made available. This is where the human can help to enhance. Your knowledge of the trip can drive you towards selecting the best way for the car to provide the estimate. If you believe the experience over the last 30 minutes is a good gauge of what is to come use that estimate. Use instantaneous if you believe the data right now is better than what the car experienced in the past (i.e. you'll be climbing a hill for a while)

    The owners of Nissan Leafs have coined the term "guessOmeter" due to the erratic jumps in the estimated range during a given trip. That is because they (me included) were only given a single number with absolutely no other data. Tesla makes this estimate more transparent to the user by providing more information about the source of the data being used to make the estimation.
     
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  8. chris5639

    chris5639 Member

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    BTW, as a software developer, I can imagine Tesla collecting the experience from its entire fleet to feed into the range estimator. It would not be easy to implement as factors like the diameter of the wheels for each car, the temperature, wind and other factors I mentioned above would have to be considered. However, like all software, it can be implemented in stages and improved over time. This is not unlike how the Waze app reports on traffic conditions based on the experience of all Waze app users on the road.
     
  9. tomas

    tomas Traded in 9 rep bars for M3, used to be somebody!

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    That uncertainty goes away if you put a destination in nav and use the trip energy tab. Then it will account for elevation and is quite accurate. All of the other factors except wind are quite minor and will show up in adjusted estimate as you drive. It is worth doing external wind check if you have a tight trip.
     
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  10. chris5639

    chris5639 Member

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    All true but speed and rate of acceleration are big factors as well. It will do a good job estimating based on past speed but any dramatic changes will have a moderate effect on range.
     
  11. tomas

    tomas Traded in 9 rep bars for M3, used to be somebody!

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    Those are all controllable. If most important thing on a leg is range, then the trip chart will tell you 10 miles in that you are going too fast.
     
  12. chris5639

    chris5639 Member

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    Again, all true but how it tells you is the point. The OP's original question was around the difference between instantaneous vs. average range. I tried to explain how it estimates the range and the difference between those two methods. Yes, you can infer that your current actions have a negative effect on the range but first you must understand what you're looking at. Some, maybe most of us, understand techniques to maximize range but that wasn't the original question.
     
  13. tomas

    tomas Traded in 9 rep bars for M3, used to be somebody!

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    please go back and read. It wasn't. Someone asked that in post #5. Origianal post was asking for a turorial on how to read the energy graph. I'm not sure where you are coming from. You posted about the Leaf "guess o meter". What does that have to do with the Tesla? Anyway, I think it is important that all Tesla owners understand both energy graphs, and know to how use the trip graph when range really matters... and also know techniques to extend range if/when they get in a pinch.
     
  14. chris5639

    chris5639 Member

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    Yes, post number 5. Same original person. I was trying to help by answering the question and not to debate about what can affect the range. I felt the Nissan Leaf reference was interesting because it shows a design of estimating range that leads to confusion and arguably a lessor design as compared to Tesla's implementation. Again as it relates to the specific question. I felt it was relevent and since I own both cars I felt I had a good perspective on the different interfaces. I'm sorry you didn't appreciate it. You reponded to the factors I stated having an effect on range and said none of those mattered but incline. I disagreed by stating that speed and acceleration are big factors as well. Not sure why you are now arguing. I have not interest in debating this with you further and I'm sorry if I offended you.
     
  15. Ormond

    Ormond Member

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    I find all the electronic terms confusing too. I need "Tesla for Dummies."
     
  16. roblab

    roblab Active Member

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    Being OLD, I too am confused about all these electronic terms, and I used to teach physics.

    Our problem is, we grew up with "miles per gallon". We all understood that if we put a gallon of fuel in the tank, we could drive so many miles.

    Watt hours per mile is like saying "this many teaspoons of gas will take you a mile". It would be more comparable if they would say "miles per kiloWatt hour" (a thousand watt hours), and we could think of kilo Watt hours as gallons. Unfortunately, "our miles per gallon on electricity" really sucks, as we get around 3 miles per kWh, but it's at least pretty cheap fuel. Our Tesla "gas tank" holds the equivalent of about 3 gallons of gas, but here again, we get pretty good mileage.
     
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  17. TMC Bubba

    TMC Bubba Member

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    The energy content of a gallon of gasoline is about 33.7 kWh, so 3 miles/KWh is around 100 MPGe. The EPA rated the S85 at 89 MPGe.

    Don't you love the units?
     
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