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Newbie - mileage question

Discussion in 'Prime Fuel Economy & EV Range' started by Moe_b, Nov 12, 2024.

  1. Moe_b

    Moe_b Junior Member

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    Just got a used 2020 Prius Prime XLE with 161,000 miles a couple of weeks back. I absolutely love it and I am surprised how solid the vehicle feels even after that many miles. It was well maintained by previous owner.

    FIRST, I have charged the plugin battery 4-5 times and every time I get right around 19-20 mile EV only range irrespective of whether I drive very lightly or a bit aggressively. I see people report 30+.

    SECOND, I am driving highway miles. My one way trip is 120 miles. I use cruise control at 65 miles per hour. I start with a full charge on EV Auto mode, after it depletes, it converts to regular hybrid and I use the ECO mode. After about 600 miles, I am averaging about 64 mpg... but people report 100+ mpg.

    Should I be concerned with both FIRST and SECOND above? If yes, what can I do about it?

    Tire pressure is 35 psi all around.
     
  2. schja01

    schja01 One of very few in Chicagoland

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    I wouldn't be. Yours sounds very normal.
     
  3. Danno5060

    Danno5060 Active Member

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    FIRST: That's an estimated range - based on what kind of driving the car has in its recent history. If you drive a lot of highway miles, use the gas pedal aggressively, and the brake pedal aggressively, you won't get the optimal miles per gallon. The car really does better in the city, where you've got much lower speeds, and can take advantage of the dynamic braking more. That's true for regular Prius driving too. My wife (who is a teacher) drives mainly highway miles during the school year. Our 2019 Prime was showing a fully charged EV range closer to 20 miles at the end of the school year. During the summer, we used the car for short trips in town, and its fully charged EV range came up to closer to 28 miles. Same car, same battery, different driving styles.

    SECOND: The measurement of MPG ignores the electric miles. If you consistently took trips of less than 25 miles, you'd be measuring 999.9 MPG. The standard Prius of that generation is rated at 54 City and 50 Highway. Since the first 20-25 miles are essentially free (according to the way the Prime calculates the MPG), 64 MPG sounds about right for the type of driving you've reported.

    I wouldn't be concerned. That's consistent with what I've seen with our 2019 Prius Prime Advanced. With the MPG you've seen, it also sounds like your driving style is fairly conservative, so there's not much to be gained there - especially without pissing off all the regular ICE drivers on the roads behind you.

    That tire pressure sounds fine to me. That's what I normally use for the summers around here. For winters, I bump that up by a couple PSI to keep from tripping the tire pressure alarms on cold days.
     
    pasta4breakfast likes this.
  4. BiomedO1

    BiomedO1 Senior Member

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    Your missing a few inconvenient truths & facts....

    First
    , your traveling at highway speeds so your battery will deplete faster and it's an old battery with 161K on the clock - so some degradation and beyond it's 150K mile traction battery warranty. Still pretty impressive, I'd say.. I believe Toyota optimized the EV motor around 45 mph. whenever your on either side of the power curve - it gets less efficient. I also run my tires at 40 psi. all around.

    Second, those claiming 100+ mpg is doing so on much shorter hops and mainly on shorter EV only trips. I'm one of those and my round-trip commute is 30 miles - 25ish miles on EV and the rest on ICE. I could do the entire trip on EV, if I can find an available charger at work - Usually monopolized by the BEV'er, so I rarely get to charge at work.

    Not everything on the internet is true and if they are telling you the truth your not getting all the related facts.....

    Hope this helps.....

    @Danno5060 I guess we were both responding at the same time....LoL
     
    Danno5060 likes this.
  5. Moe_b

    Moe_b Junior Member

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    Thank you both :).... Question for @Danno5060, are you sure the MPG calculation ignores the EV miles? If that's the case, and my 64 mpg is purely HV mpg then technically on my 120 mile trip the calculation would be following:

    - since first 20 miles was EV only, total gallons used = 100 miles / 64 mpg = 1.5625 gallons
    - total MPG including the "free" EV miles = 120 miles / 1.5625 gallons = 76.8 MPG

    So my total MPG in that 120 mile trip would be 76.8 MPG .... correct?

    But I personally think that the car does include the free EV miles into consideration when calculating the MPG on the gauge.
     
  6. kiwiscoot

    kiwiscoot Junior Member

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    My 2019 Prime does not ignore the EV miles but includes them in the displayed calculated mpg - l/100km readout. So in my case where I do most of my rides fully on EV my car shows l/100kms which started at 4.3l/100kms and is now slowly tracking down and at 2.2l/100kms for 750kms since refill. Fun to watch it slowly tracking down, will it get to minus l/100 so in theory making fuel while I drive?!:LOL:. So if my car was showing MPG it would slowly track up until it showed the magical 999.9MPG.

    Your true MPG

    120miles/64MPG = 1.875 gallons

    100/1.875gallons = 53.33MPG

    but to get true picture bring up the Trip stats to see actual % of distance on EV mode.
    CapturePrius.JPG
     
    #6 kiwiscoot, Nov 12, 2024
    Last edited: Nov 12, 2024
  7. Danno5060

    Danno5060 Active Member

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    @Moe_b
    Reset the trip meter at the beginning of your day. You'll see your MPG is 999.9 MPG (gallons used will be 0) until the ICE kicks on. From there, it will drop as you actually use gasoline (unless for some reason it kicks the ICE on for some reason).

    Calculating the EV MPGe (mile per gallon equivalent) is a complicated calculation, requiring data your car has no way of determining (cost of a kWh of electricity, cost of a gallon to calculate the gallon equivalent of a kWh), so there's little chance that the car can calculate the overall MPGe.
     
  8. BiomedO1

    BiomedO1 Senior Member

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    the odometer and trip counters are always correct in your distance traveled. MPG is derived from distance traveled divided by gallons used. If the ICE doesn't turn-on, you get a divide by zero error (undefined, mathematically), so Toyota engineers defined it as 999.9 miles/gallon. When your ICE kicks on, You'll see that number drop. After a while it'll get relatively close to actual MPG, because your slowly working off those "free" EV miles out of your calculations.
     
  9. vvillovv

    vvillovv Senior Member

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    averaging 64 mpg on a 120 mile drive sounds pretty good to me. There are reports of exceptional mpg all over this chat board. There are many tricks to getting better mpg in a Prius, some are one offs ( (I've had quite a few of those myself) and some are not so honest reviews and some leave out small details that can make a big difference in how other read them. That exceptional reports with a grain of salt or sand, they are not always what they appear on first read.

    Using EV Auto seems to be working for you on your 120 mile drive.

    You can always try HV mode for your trip and see how it stacks up against EV Auto mode during your drive.
    It's as simple as pushing the EV/HV button.
    Keep in mind as the weather gets colder it takes longer for the engine to complete it's warmup cycle. The slower you drive during the warm-up cycle the faster it gets over with and the mpg can start to raise while the Prius does it thing(s).

    Learning how to raise your EV miles range is not easy. At 167K miles it's going to take many many EV trips to learn which ones help and witch ones hurt your EV range.
    Since your 20 miles showing now has been burned into the cars history data. Even at 90 k miles in our Prime it's way more difficult to improve our EV estimated miles than it used to be when the car was newer.

    Colder weather the EV range typcially drops off, but in EV Auto, it may not drop as much as it does for those of us that can use EV only for most of our tirps. In spring as the weather warms and the Prius warmup cycle also shortens, both EV estimated miles and mpgs typically raise again for winter lows.