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When does the fuel light turn on?

Discussion in 'Gen 3 Prius Main Forum' started by Fireboy, May 5, 2015.

  1. fuzzy1

    fuzzy1 Senior Member

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    You may not be stuck with 48-50 mpg, it depends on the hills. Can you give us an idea how steep, and how much elevation change per hill, is typical?

    My view is that the common uphills don't make all that much difference, it is the downhills that make or break your overall round trip MPG. The Prius engine can climb many hills with nearly the same fuel conversion efficiency as level cruising. The gravitational energy of the climb is saved as elevation, then is later recovered and used -- or wasted -- on the descent.

    Short or shallow hills that you can glide down without touching the brakes are perfect. If speeds are under 45 mpg, you should be able to reach about 75 mpg. Crest the peaks somewhat slower than speed limit if necessary, and if traffic allows, to minimize speed violations on the way down.

    Longer or somewhat steeper ones that demand some braking will hurt, but not terribly bad if you can use entirely regenerative braking (HSI bar not completely filling the CHG section) and not fill up the traction battery. Cruise control can also be useful here, as it will retard downhill speed with purely regenerative braking, but this method is not always compatible with road and traffic safety.

    Hills long enough to fill up the traction battery well before the bottom, or steep enough to require friction brakes or B-mode engine braking, are MPG killers. And you are just stuck with the loss.

    The little tiny blinking pip is neither bright nor a contrasting color. In an overall colorful scene, it is monochromatic.

    The very last car I drove with only a mechanical needle was a 1970s model, which I sold more than thirty years ago. Except for the Prius, every vehicle I've owned since has had a low fuel warning in a contrasting warning color, brighter than the non-warning display elements. My other current car even has TWO of them.

    As for cruising range and DTE, those are not permanent displays, but are just some choices on a menu too large to be displayed all at once. Like many people, I prefer other displays, and am not constantly cycling through the menu.

    That said, my only accidental out-of-fuel event was the very first tank of that 70s car, with its needle still above E. The two more recent events were planned experiments, a la Bob Wilson's engineering tests, complete with a backup fuel supply.
     
    #41 fuzzy1, May 9, 2015
    Last edited: May 9, 2015
  2. The Electric Me

    The Electric Me Go Speed Go!

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    To each their own. I still stand by the idea that The Prius offers plenty of warning that it needs gas. In my experience cruising range and DTE are the same numbers. Yes, you have to "pick" the menu that displays them, but you have two choices. For me once The Final pip is blinking, picking one to view "permanently" as I go the final X miles on the tank is pretty easy. That's assuming you don't keep one of the displays permanently on one of the two choices.

    My 2010 Honda Fit had a beautiful needle gauge, along with a "Low Fuel" warning icon. It worked fine. It was however all the warning it gave you, it was all the warning anyone I think should need.

    There is DRIVER responsibility in knowing and being able to know when your vehicle needs to be refueled, and unless it's the first few tanks or maybe first few weeks of ownership, I don't buy that The Prius doesn't warn you enough.

    The Prius dash board is monochromatic, but clearly readable. That "tiny" final blinking pip is made rather obvious in it blinking singularity on a display gauge where all the OTHER pips are now NOT illuminated. So even if it's time to get your prescription changed on your glasses, you should be able to notice that that rather big and obvious arc of lighted pips have slowly vanished. When you ONLY see one? That's a warning.

    I just think griping because once the Prius reaches the final pip...there isn't an accompanying idiot light that spells out "Low Fuel" is kind of ridiculous. Auditory Beep (Toyota Could Of Done Better, at least make it beep 2-3 times) plus blinking final pip....plus two possible displays showing DTE and/or Cruising Range either singularly or both on two different displays?

    Again how much warning do you need? I've done fine with just a needle gauge and a single light. The Prius is nearly a hyper active child wanting to go to the amusement park in terms of letting you know fuel is getting low.

    To me? Not a Problem.
     
  3. fuzzy1

    fuzzy1 Senior Member

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    Moi? The Prius has adequate warning. I learned to work with a single needle and no warning light more than thirty years ago, once the aforementioned incident provided a calibration point for that particular car's fuel gauge. For all subsequent cars, I used refills to calibrate each gauge mark.

    But I know plenty of other people who would benefit from better warning. By monochromatic, I don't mean just the fuel gauge, but the entire dash display. The brighter contrasting warnings in my other modern cars have clearly been better user interfaces, at least for that particular item.

    The additional warning stages and finer low-tank resolution of my current Subaru are clearly superior to the Prius and all previous cars.
     
    #43 fuzzy1, May 9, 2015
    Last edited: May 9, 2015
  4. The Electric Me

    The Electric Me Go Speed Go!

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    I'm not saying other vehicles might not have brighter prettier colors, or even admittedly better interfaces, what I am saying....

    Those other people that could use better warning? Are idiots if they can't figure out how to know when to refuel The Prius.
     
  5. fuzzy1

    fuzzy1 Senior Member

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    There are an incredible number of idiots out there. That hasn't been sufficient reason to yank most of their drivers licenses.

    Actually, at some level, most people are idiots. But the degree, and the specific subject matter, vary enormously. That is one reason user interface design has become very important.
     
  6. The Electric Me

    The Electric Me Go Speed Go!

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    I'll concede only this much.
    Toyota kind of dropped the ball with the low fuel auditory beep warning. It's so short as to be very easily missed.
    I kind of find it funny that if you put The Prius in reverse, Toyota felt it OK to have it start beeping constantly and repeatedly. BUT if you get low on fuel? You better keep your ears ready, because your only going to get one short beep. The Prius is capable of making Long single beeps, multiple short beeps...Toyota COULD of done a better job.

    For what is suppose to be a Halo vehicle for Toyota, I do also think the dash has become dated and stale. I even thought this is 2010 when it was new....didn't really compare well with the Dash of the Ford Fusion Hybrid. Even then it was 2010 and The Prius dash looks more like something cutting edge for 1981.

    I still think the Prius gives PLENTY of warning in when to refuel. BUT I agree there are improvements needed in the whole dash. I'll be really curious as to he form and function of the next Gen Prius dash. As well as whether the flying buttress continues on.
     
  7. Paul Schenck

    Paul Schenck Active Member

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    That's an interesting idea I bet I could make a "Fuel up Fool" wave file and have it play by setting an reminder in the maintenance every 350 miles



    iPhone ?
     
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  8. bisco

    bisco cookie crumbler

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    how difficult would it be to have 'LOW FUEL' appear on the screen for us idiots?(n)

    "WARNING WILL ROBINSON!"
     
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  9. Paul Schenck

    Paul Schenck Active Member

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    I just don't think fuel is a big deal!
    When I'm out I use the battery to limp to a station. I could also keep a can in the back for extremely stupid moments. Or just risk pissing of another F150 by filling up for $30 and tipping my hat as I drive around him leaving the pump to empty his wallet! Good Day!


    iPhone ?
     
  10. defrankond

    defrankond Member

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    I cannot get 60 out of mine. I doing lucky to get 50. These monster 17" back breaking LOW ROLLING RESISTANCE TIRES ARE KILLER for fuel economy and gas mileage on a Prius

     
  11. bisco

    bisco cookie crumbler

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    they look good though!(y)
     
  12. walter Lee

    walter Lee Hypermiling Padawan

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    As Scotty might say "she canna take much more of this! She's gonna blow Capt'n!"
     
  13. bisco

    bisco cookie crumbler

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    no sign of intelligent life down here.:cool:
     
  14. sosarahsays

    sosarahsays Member

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    LOL, The Electric Me, I loved your rant. I can't for the life of me figure out why people ever run out of gas. The indicator is right in front of our faces! When mine gets down to two pips, I switch from the MPG read out on the HSI to miles-to-empty. I try to pull in and get gas around 50.

    OP Fireboy -- Welcome to Prius Chat and Prius ownership! I wonder if you would get better mileage in regular, not power mode? I think I have read on here that it doesn't make a noticeable difference, but you really don't need all the horses engaged going down hills, so maybe running in regular or eco would improve your mileage? Even if you're just coasting, perhaps the Prius is still technically using more power in power...? That said, don't take my word for it. I am primarily a short distance city driver, so I only see 44-48 mpg on any given tank. I definitely get better mileage on the highway/longer trips, despite the EPA "promises." That said, I think what Paul Schenck said about the car getting to know you is interesting. I bought my Prius CPO, too, and haven't had a major service with the battery disconnected (I assume they don't disconnect it for oil changes). I wonder if my mileage will improve after a major service. I don't have one scheduled, but am excited to see!
     
  15. fuzzy1

    fuzzy1 Senior Member

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    Aside from minor tweaks to cruise control and climate control, the ECO/Normal/PWR mode selection doesn't directly change the machine's mpg. It just changes the user interface to the throttle control. This should enable many drivers to get better mpg with an interface that better fits them. Other drivers may do better in a different mode, or may get no change at all.

    Use what mode works best, or feels best, for you. It makes no difference to the machine.
     
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  16. Mendel Leisk

    Mendel Leisk Senior Member

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    I think it's falling on deaf ears, fuzzy. D.O. for the misguided conviction that the only way to improve mpg is to risk running out of gas.