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What kind of hand calculated MPG numbers are you getting?

Discussion in 'Prime Fuel Economy & EV Range' started by Lemooron, Jan 24, 2017.

  1. Lemooron

    Lemooron Junior Member

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    Being that we have determined in another thread that the Prime's dash mpg's are higher than the hand calculated mpg's what kind of hand calculated mpg's are you Prime owners getting?
     
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  2. thatoneraccoon

    thatoneraccoon Active Member

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    So far I have only used roughly 1/2 tank and have 1200 on the odo
     
  3. priuscatprimeguy

    priuscatprimeguy Senior Member

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    I still have 3/4's of a tank and have 777 miles on the odo. Same tank of gas since I picked up my Prime at the dealership November 30, 2016:eek:
     
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  4. CaliforniaPrius

    CaliforniaPrius Active Member

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    53 with 85% hwy, speed of 79mph

    Not going to plug it in anymore. By this calculation and $2.5/gallon, electricity costs the same as gas pump.
     
    #4 CaliforniaPrius, Jan 25, 2017
    Last edited: Jan 25, 2017
  5. Samprocat

    Samprocat Active Member

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    Simple way is to check your sdeedometer with GPS speed on phone or GPS device and from that you will see true MPG.....error will increase with tire wear pressure above factory ... speed....etc

    Posted via the PriusChat mobile app.
     
  6. bwilson4web

    bwilson4web BMW i3 and Model 3

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    With or without plugging in?

    I am only interested in the trip meter error and fuel consumption of the new control laws. I need it for trip planning.

    Bob Wilson
     
  7. Samprocat

    Samprocat Active Member

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    40 Fahrenheit temp.
    2 person
    With other staff in trunk 800 lbs
    Without hard acceleration
    Mostly highway speed 67 average
    With 20 miles US route 60 MPH
    490 miles trip from Lincoln NE to Denver CO
    Elevation start 1200 feet end 5000+ feet
    My hand calculated MPG 59
    Nothing have try to make better MPG....
    Not following Big to drift behind
    My cab heat was set on Auto 73 Fahrenheit
    Some places i was going 80 MPH
    Fuel used was Premium
    Didn't try any other options for better gas mileage..beside one that kick in once you start the car and drive
    So I'm definitely sure that i can easily hit 70 MPG if i was going after ultimate MPG.....
    Tires are on factory pressure
    Car have now 3800 miles.....
    With fresh full synthetic oil change before trip
    And this are hand calculated miles.....my speed error was between 60-70 1.6 less than true speed tested by GPS....
     
  8. Joe Lopes

    Joe Lopes New Member

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    There is definitely a break point, based on price of electricity vs. price of gas. For me at 20 c/kWh it's about $2.50/gal, but the electric range is about 10-15% less in the winter. If you can, get on a time-of-use rate and charge at night, which makes a big difference, but if the rate is on your whole house, it may not make sense (e.g. people at home during the peak time). Also, in calculating your electric price, subtract fixed charges from your bill first (e.g. customer charge) since you realy want incremental cost and fixed charges have to be paid regardless of usage changes. Then divide kWh into variable costs to get the "incremental" rate.
     
  9. Andyprius1

    Andyprius1 Senior Member

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    104 and 106 mpg.
     
  10. stevepea

    stevepea Senior Member

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    This hasn't been precisely measured, but I can give you an idea. For the job I'm doing for the next couple months, I constantly get a displayed daily MPG of just over 100MPG (usually about 103MPG) for a 79-80 mile round trip commute, in which I charge at home the night before (so the EV range helps the MPG numbers). The number varies slightly, as on some days I go in with rush hour conditions, other days I go in at non-rush hour times... but it's always been in the "just over 100MPG" range, usually about 103 (charging the night before), and so far since starting this commute I haven't used the Prime for any other driving other than for this commute.

    Now one time I filled up the tank after doing 11 of these 79-80-mile commutes, and it took just under 9.0 gallons (like 8.995), filling it up in the same way I had beforehand (as well as charging it each night). So you can do the math... it winds up being something like 97-98MPG. Slightly lower I guess, but not too much so. This wasn't measured precisely, as I topped off the tank when refueling (though I also did so initially), but the "amount" of topping off may have been different. Maybe the better experiment is not to top off, but both times just have it stop when refueling stops on its own. At any rate, it appears it's slightly less in the real world, but only by a tiny bit.

    Where I live (SoCal) electricity is EXPENSIVE. I always manage to still keep it in the lower tier, but it's still 16c/kwh... and the normal "middle tier" is 25c/kwh (and SCE has petitioned for a rate increase). But then, regular gas is about $3.09-$3.20 here right now.
     
    #10 stevepea, Jan 26, 2018
    Last edited: Jan 26, 2018
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  11. Andyprius1

    Andyprius1 Senior Member

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    You do realize that Premium gasoline in not recommended. Nice figures for the commute tho.
     
  12. Andyprius1

    Andyprius1 Senior Member

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    You may want to try conditioning the car 1/2 hour before departure, I believe it gives a bit more ev range.
     
  13. stevepea

    stevepea Senior Member

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    So.. just shampoo isn't good enough?

    But seriously, what do you mean by "conditioning"?
    (I always start out in EV for the first 1 mile until I reach the freeway)...
     
  14. Andyprius1

    Andyprius1 Senior Member

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    Hit the AC button on the Fob 2X and the heat or Air Conditioning will start. Try to set the temp you want beforehand. Takes 20-30 min. I never timed it. It seems to produce a bit more range.
     
  15. muleman

    muleman Junior Member

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    My car is Killin it!!! I am over 1000 miles now and 183mpg. Picked up the car Jan 2 and have not filled the tank. It's been pretty cold this month with a couple good days. I also have snow tires mounted 1517188132402.jpg

    Posted via the PriusChat mobile app.
     
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  16. stevepea

    stevepea Senior Member

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    More range even on a pleasant day when I don't need to use either heat or AC when driving? Not sure why that would be. I assume doing the pre-conditioning would use more energy (either from the traction battery or from the wall outlet if it's still plugged in). Maybe I'll try it once, though I've never used it before.
     
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  17. Mendel Leisk

    Mendel Leisk Senior Member

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    You're inferring the difference between dash displayed mpg and calculated is due to speedometer over-reporting? Sorry, not buying that:

    The car has a fairly accurate measure of distance travelled (as displayed on the odometer), and the gas consumed. Toyota mpg displays are chronically positive, anywhere between 5~10 percent. Our 3rd gen's reporting settled in on 7.4% positive bias, pretty much unbudgeable after 142 fillups.
     
    #17 Mendel Leisk, Jan 29, 2018
    Last edited: Jan 29, 2018
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  18. Andyprius1

    Andyprius1 Senior Member

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    Preconditioning does at least three things, maybe more. I am speaking wall plug in only.
    1. Prepares car to desired temperature
    2. Seems to...lessen time engine needs to run on initial startup
    3. Extends range, minimally, perhaps 1-2 miles.

    I am not too concerned with my household electric consumption as I have 24 solar panels outside.
    PS. In ref to a pleasant day. The EV range is proportional to the outside temperature. the warmer, the greater range ( to a reasonable degree )
     
    #18 Andyprius1, Jan 29, 2018
    Last edited: Jan 29, 2018
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  19. Andyprius1

    Andyprius1 Senior Member

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    Post 14 That should be Hold Fob AC button down until taillights blink.
     
  20. Andyprius1

    Andyprius1 Senior Member

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    Something I just discovered, in exploring the settings I found a readout that shows Avmpg, this totally agrees with my calculated math at fill-ups. Simultaneously I’m now getting constant odometer readings showing. I always thought 199.9 mpg(e) readings were very much fictitious. Of course now I have lost my Highway speed Limit notification. Am afraid if I look for it, I’ll lose something else.
     
    Mendel Leisk likes this.