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How much gas is left in the tank when the light comes on?

Discussion in 'Gen 4 Prius Fuel Economy' started by krmcg, Oct 10, 2016.

  1. bisco

    bisco cookie crumbler

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    i don't think that is correct. if it says 50, you should have 150 miles of fuel left.
     
  2. KV55

    KV55 Member

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    That could well be true, it is just that I am seeing the distance to empty go to zero before the original DTE distance is travelled, even on a fairly constant mpg.
     
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  3. bisco

    bisco cookie crumbler

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    agreed, it's not an exact science.
     
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  4. axle2152

    axle2152 Active Member

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    Another thing to keep in mind is consider terrain. If the range shown is say... 60 miles and you're about to go up a 8% grade mountain for the next 5 miles you could eat through 20 miles or more of the range doing that (although you can coast down the other side).

    Simply put, the amount of fuel burned varies greatly....none to quite a bit depending on what you're driving over, weather conditions, tire pressure. Not sure where gas is drawn from the tank but if you're going up or down steep grades could run out of gas despite having enough fuel otherwise.

    I have pushed it around 30 miles after showing 0 range but rather not run out of gas, not particularly good for the car -- fuel pump, etc. At least you can't attempt to start the car again and again and burn out the fuel pump.

    It is safe to run down to 0 range, just don't intend to go 60 miles more, unless you don't have a choice...if you're seeing one of those signs for instance.

    Also weight is irrelevant with gas if you ask me. A full 11.5 gallons of gas is about 72 lbs. I really doubt this is a significant factor in fuel economy and any savings from running with less gas would be gone from making extra stops refueling. In other words when driving cross country you're better off with a full tank and keeping moving. Avoid driving over 75 MPH and as long as you're on relatively level ground cruise control works well on the highway. So don't run the tank dry and while it is good to know in an emergency, fill up your tanks.

    In my experience I usually don't put more than 10.3 gallons in the tank on a refuel even if the range has been zero for 15-20 miles. How far can you go? It varies, could end up being as little as 11 miles or as much as 80+, it all depends. Having a hybrid means you'll likely see outliers as it all depends on where you're driving, how you're driving, weather, how long, etc.
     
  5. fuzzy1

    fuzzy1 Senior Member

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    I would assert that "seeing one of those signs" is the wrong time to find out how far it will go. It is better to backtrack to the most recent available fuel. And if none is currently open, camp out in their parking lot (or other nearby place of convenience) until they reopen. If you are going to be stranded alone without fuel in scorching heat or a blizzard, it is better to be camped next to a convenience store where you can break in for survival supplies while waiting for help to arrive, than out in the middle of nowhere.

    Do all your 'below 0' range testing at a time and place chosen for your convenience, when failure doesn't compound an already difficult situation. I.e. when you see these signs, is not the time to discover that your car is like my first one, which ran dry before the fuel gauge needle even dropped to 'E'. Or like my current Subaru(*), which has no safety margin built into its Distance To Empty display:
    [​IMG]
    [​IMG][​IMG]

    (*) To be fair to my 2014 Subaru Forester, where DTE=0 really does correspond to no fuel remaining -- it has numerous other low fuel warnings, much more in-your-face than my Prius' warnings, well before fuel starvation. No non-comatose driver can legitimately assert that it lacks adequate warning.
     
    #25 fuzzy1, Jul 24, 2017
    Last edited: Jul 24, 2017
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  6. SacMcNasty

    SacMcNasty New Member

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    I love seeing these derragatory posts meant to demean Prius owners from testing their cars' limits.

    During my travels I seem to hit the trifecta of MPG defying odds:

    -I travel a high grade mountain range and 200 mile trips 20 days out of the month.

    -I carry at least 2-500lbs + of items people consume

    -During my testing I've pushed my to its limit of DTE...

    Results: (Fill up before hitting 700miles)

    10.719 gallons
    Trip: 687.7mi
    Avg: 65.7MPG (instrument)

    Gas light comes on: 572.9mi
    Moment I hit 0 Bars to fill up: 637.7mi

    Here I greatly used a combo of coasting and pulse and brake. Used EV mode to depletion of the battery. As a result you will see I used even less gas than this previous amount.

    10.658 gallons
    Trip: 700.3mi
    Avg: 66.1MPG (instrument)
    Gas light: 610.8mi
    Moment I hit zero bars: 651mi

    I'm sure there will be comments here and there but clearly she still drives like new even with 2 years worth of miles in 6 months...best MPG to date...

    Earlier averages were 540mi on a fill up with 55MPG averages.

    Posted via the PriusChat mobile app.
     
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  7. axle2152

    axle2152 Active Member

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    I wouldn't want to run out of gas unless either had a can of gas with me with enough fuel to restart the car or within one mile of a gas station.

    One thing to be clear on though is other vehicles, specifically non-hybrid, it is a really bad idea to try restarting the car after it has ran out of gas. The fuel pump runs dry and can burn out the pump which is often pretty expensive to replace.

    I would also venture to say that running out of gas in a Prius while you can't attempt to restart the ICE, it's probably not good for the car.
     
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  8. KV55

    KV55 Member

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    I agree with axle2152 but as this is a thread about how much gas is left in the tank and not one about is it a good thing to run out of gas it is like the amber fuel light a warning. I refueled this morning with 34 miles left on the DTE. The amber warning light is consistent, coming on at 40 miles to empty. I added 37 litres for 662 miles of travel and that tells me there are 6 litres remaining. It might be that the car cannot use all 6 litres but if it could that would be another 110 miles. SacMcNasty is seeing 50 miles beyond the zero point, suggesting the car can at least use 3 litres after the zero point.
     
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