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Consumption Screen.... lifetime mileage???

Discussion in 'Gen 2 Prius Main Forum' started by spencer999, Dec 10, 2004.

  1. spencer999

    spencer999 New Member

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    hello again...

    so i've come to report that after my 6th day of ownership (lots of short trips and cold weather) i've had to refill my new prius for the first time.... I was at 312 miles when i finally pulled over (just a few minutes of the "add fuel" notice appeared).... i was going to continue for a while since i heard that most people get around 100 more miles after that signal comes up... but i got nervous... so i did.

    I refilled 9.2 gallons, and when i drove off i realized i noticed that on the consumption screen it had reset to 0.0 mpg and 000 miles... which is great... i didn't even have to hit reset...

    but here's my question. how do people know this "lifetime mpg"?? now i only see the mpg on my current tank of gas. or do i? i'm a bit confused. are people just keeping track of their lifetime mpg or is there somewhere on the display to find that?

    thanks! (a beginner)

    lawrence
     
    #1 spencer999, Dec 10, 2004
  2. Tempus

    Tempus Senior Member

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    The Prius doesn't keep lifetime mileage stats.

    Just keep a running total of all the fuel you put in and divide into the odometer reading.

    Most people who track it use a spreadsheet or a PDA Fuel Log.
     
    #2 Tempus, Dec 10, 2004
  3. john1701a

    john1701a Prius Guru

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    Once you've reached about 20,000 miles, a Lifetime MPG display would have grown to the point of being completely worthless anyway. Since at that point, it takes several hundred miles to even have a 0.1 MPG difference. And because the margin-of-error is about 1.4 MPG, the value is lost.

    It's just a Statistics 101 reality with any vehicle.

    So those of us that report Lifetime MPG are doing it by hand, logging each fillup on a paper or software.
     
    #3 john1701a, Dec 10, 2004
  4. rflagg

    rflagg Member

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    after 20k, my last tank took down my lifetime mileage by 1.0mpg. It does get pointless, as far as a running statistic goes, after a while - but I think the number one question I get as a Prius owner is 'what's your mileage' - they aren't concerned about the current tank, they want over the life of the vehicle. Unfortunately, the only way to track it is by hand spencer, but in doing so, you'll probably take better care of your car by noticing trends, etc. - and that's definately a plus.

    -m.
    -m.
     
    #4 rflagg, Dec 10, 2004
  5. efusco

    efusco Moderator Emeritus
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    matt
    You must've been doing some serious rounding off or had a terrible last tank of gas if you truely dropped a full 1 mpg on your LMPG.

    Some quick calculations using 20k miles @52mpg as a start and 20350 miles @ 51mpg you would have used 14.4 gallons to go that 350 miles (that's 24.3 mpg). Obviously, depending upon how much you round off the numbers wouldn't need to be quite so extreme, but it seems difficult to drop a full 1 mpg on a single tank after 20k miles...though not impossible.

    My shifts all seem to be in the 0.05-0.1 mpg/tank now at just over 15k miles...if any shift at all.
     
    #5 efusco, Dec 10, 2004
  6. rflagg

    rflagg Member

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    gah, I did say 1.0mpg. Sorry, that should read .3mpg. it went from 51.3 to 51.0 after a 'horrible' tank of 43.8mpgs.

    -m.
     
    #6 rflagg, Dec 10, 2004
  7. efusco

    efusco Moderator Emeritus
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    That's a bit more believable.
     
    #7 efusco, Dec 10, 2004
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