Prius Two Eco Tank Depletion

Discussion in 'Gen 4 Prius Fuel Economy' started by Prostalker89, May 18, 2016.

  1. Prostalker89

    Prostalker89 New Member

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    i recently bought my prius 2 eco last week. I've notice that somedays my miles-to-empty range would deplete faster than when it was at full tank (811 miles), i'm averaging 60 mpg and my commute is 30 miles round trip. Someday i'd consume 8 miles of 15 one way and sometime id consume all 15, same way. Is this unusual or common? does it depend on how i accelerate and my battery usage?
     
  2. bisco

    bisco cookie crumbler

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    congrats and welcome! yes, it's just an estimate, and compares your current driving to historical average.
     
    krmcg likes this.
  3. pakitt

    pakitt Senior Member

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    The DTE (Distance to Empty) is an estimate based on some algorithm (not clear yet which one), supposedly based on historical fuel consumption.

    When it reaches 0 though, it seems (I am going through a second tank on my Gen3 exactly to check this; results on a first tank here) to calculate the DTE based on 2.5gal/10L left in the tank. Essentially, when DTE gets to zero, you have still at least 2gal of fuel left. Which means a good 100mi worth at 50 mpg average.

    The best way though is to calculate that yourself.
    Simply take the miles driven so far, dived by the current tank average MPG and you get the gallons left in the tank. Based on that, you can make your estimations on how many miles left you have to drive.

    • E.g. (500mi driven so far) / (50mpg average of tank) = 10gal used
    • Fuel tank on Gen4 is 11.36gal) - (10gal used so far) = 1.36gal left at that point.
    • If you continue to *average* 50mpg, it means your range should be 1.36*50 = 68mi to EMPTY tank (*really empty tank*).

    Because your average MPG from the moment of calculation point onward could be lower, I'd leave a bit of leeway in the calculation to give yourself some buffer. (e.g. (1.36gal left) * 40mpg = 54.4 mi left to drive, in "comfort)

    I have never used the DTE in my Gen3, because for EU distances, it is way too conservative. When the fuel gauge beeps, it means I have still 7-8L at least of fuel and it is time to visit a gas station sooner or later, depending on where I drive in the next days (city commute) or in that specific moment (highway in the middle of nowhere - which in EU means then next gas station is *at most* 30-50 mi away...).

    There is another post where I uploaded an xls that can be customized on one's own fuel consumption averages and "comfort level" to know how much is there left to drive before the tank goes dry.
     
  4. Prostalker89

    Prostalker89 New Member

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    Thank you, Im pretty new at this so i felt a bit puzzled by the up and downs of the rate of my range going down. Id try to post some numbers once im done with this 1st tank. Id just enjoy my ride in the meantime lol.
     
  5. Mendel Leisk

    Mendel Leisk Senior Member

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    Maybe just watch the tank status blips, fill when it's getting low.
     
  6. bwilson4web

    bwilson4web BMW i3 and Model 3

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    This is what I do using 2.1 gal (US) and resetting a trip meter. I then calculate how much remains and refuel before it falls below 0.5 gal (~2L).

    Bob Wilson
     
  7. Frederickdawg

    Frederickdawg Active Member

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    Must be different on us spec models. My DTE shows 140 miles and that is approx 2.5 gallons left in tank since it takes about 9.5 gallons to click.

    LG-H901 ?
     
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