EV mileage

Discussion in 'Prime Main Forum (2017-Current)' started by ed4271, Jul 17, 2019.

  1. jerrymildred

    jerrymildred Senior Member

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    See how it levels off at about 75F and then starts to drop slightly just before the end of your measurements. If I was tracking, my measurements would go up another 20F and drop steeply right where yours start to hint at a drop. So, the warmer the better is not always true. At 95F, I get about the same range as you do at 35F. But at that sweet spot around 70-75, it's awesome. Someday I hope to see those temperatures again. We're looking at another 92+ day again tomorrow. :oops:
     
  2. Prius from Dad

    Prius from Dad Senior Member

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    Correct, no AC load. AC definitely affects EV range.
     
  3. jerrymildred

    jerrymildred Senior Member

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    Big time down here. But it had an even bigger impact with my PiP. Prime's AC is far more efficient, apparently.
     
  4. Dael

    Dael Junior Member

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    my postulation was: 1. Start out with a full battery 2. full tank of gas (=?miles) 3. during last leg of 1 trip recharge EV battery with engine and then exhaust any motive potential. = how many miles?
     
  5. Tideland Prius

    Tideland Prius Moderator of the North
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    @bwilson4web you've done these experiments, right? Thoughts?
     
  6. Salamander_King

    Salamander_King Senior Member

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    You might wait to hear from @bwilson4web for his experience on this. There are so many variables in this equation. How fast are you going? What kind of traffic are you going to have? What is the ambient temperature? What kind of terrain you are driving? Any AC (heat or cool) use? Any passenger or cargo in your car? All of them and many more other factors will affect the milage and EV range. It will be impossible to predict the precise range you will get.

    Assuming EPA published number of 55mpg and 25 miles of EV range, you will get 55x11.3=621.5 miles + 25 EV miles, total 646.5miles. I don't know how much of gas is used to get 80% charge for the last leg of EV, but the assuming the conversion is not 100%, your range will be little shorter than what you will get from all provided gas and charge at the start. So my guess is using a half-gallon of gas to get 20 miles of EV by CHARGE mode, thus total miles will be 7.5 miles shorter or 639miles when you hit dead empty.
     
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  7. bwilson4web

    bwilson4web i3 and Prime

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    This is hard to explain as there were
     
  8. Tideland Prius

    Tideland Prius Moderator of the North
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    Were you planning on finishing that thought? :D
     
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  9. jerrymildred

    jerrymildred Senior Member

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    I imagine that @bwilson4web will be back to finish that thought.

    In my limited experimentation, I got less total range using charge mode because of the losses involved in energy conversion. I didn't/couldn't document any numbers because it was such a variable situation involving changes in wind direction, hills, and stops for meals & bathrooms.

    My measuring stick was average mpg on the current tank. There was one stretch coming south on US19 in Fl. 65 mph speed limit. I did seem to get a tiny bit better mpg using charge mode and depleting the charge but it wasn't more than 1-2 mpg and that's well within the variation I'd expect from variations in wind speed and direction over the hours.

    I think a proper test would require an indoor track to eliminate wind, slope, and temperature variables. But just looking at the fact that you always lose energy when you convert from one form to another tells me that it would be very rare to gain anything with charge mode.
     
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  10. bwilson4web

    bwilson4web i3 and Prime

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    Sorry, I got distracted.

    Reset your trip meter and optionally, carry a small, spare gas can securely. My rule of thumb:
    • EV mode when off the highway
    • use hybrid mode, preserve EV charge, after you get to cruise speed
      • Follow trucks, RVs, trailers, or towed vehicles using dynamic cruise control
    • The low fuel light comes on with ~1.5 gal remaining
      • Set the car to charge the battery to 80%
    • Continue until the gas runs out within 20 miles of a truck stop or gas station
      • Slow down on EV to reach a gas pump
      • If less than 5 miles to a gas station, add spare gas to tank.
    On a 600 mile trip, there will be biology breaks. If gas prices are relatively high or you are going 'for the record,' do your business and get back on the highway. At the pump, do your 'victory' dance (looks a lot like the 'I gotta pee' dance) and take a photo of the trip meter.

    Bob Wilson

    ps. WARNING: if out of gas and EV charge, the car will coast to a stop. After adding gas, the negative battery terminal has to be removed for a power-on reset. Your tripmeter values will be lost but the car will start. Otherwise, the car will have to be towed to a very expensive Toyota service center.
     
    #50 bwilson4web, Sep 2, 2019
    Last edited: Sep 2, 2019
  11. Dael

    Dael Junior Member

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    Thanks Mr. Wilson!

    Sounds like a dangerous proposition! Scientists have to consider all possible outcomes!
    Jerry said losing about 1-2 mpg to charge. Towed for a power reset? really? how many times has this happened to people? Not a very user friendly experience. Thanks guys!
     
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  12. Felt

    Felt Senior Member

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    Correct me if I'm wrong, but on my Toyota Avalon Hybrid, the A/C compressor is powered by an electric motor .... not the ICE.
    I acknowledge that the ICE must generate electricity to run the A/C compressor, but it is minimal.(I would think)

    IF there is indeed a impact on milage from summer heat .... I'm thinking it must be from another cause. Air density? ICE in-efficiency? Rolling resistance from sticky hot pavement? And don't forget, motorist are much more prone to sit in line stopped at the drive-up with the A/C on.

    I would think that riding with the A/C on and the windows closed would more than offset any increase electrical demand from the ICE to run the compressor electric motor.

    Finally, I have not noticed any decrease in fuel economy on my Avalon Hybrid in the summer. If there is any, it's too small to accurately measure.
     
  13. Washingtonian

    Washingtonian Active Member

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    The impact on mileage from summer heat pertains to EV mileage, not ICE mileage. The traction battery is more efficient in warm weather than in cold weather. For example, in January I can expect to have 23-25 miles available after charging the car. In August, that has been 30-31 miles. Some get better, but I drive in the PWR rather than the ECO mode and am willing to make the trade off.
     
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  14. Felt

    Felt Senior Member

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    Washingtonian - Thank you for your comment.

    Actually .... my comment was prompted by: " AC definitely affects EV range." from an earlier post.
     
  15. Salamander_King

    Salamander_King Senior Member

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    AC use definitely reduces EV range for PRIME. Heating by heat pump uses more battery power than cooling does. See this thread for detail. Estimated EV penalties for various heating cooling and lights | PriusChat

    Here is data from my AC load ratio which I believe is a measurement of traction battery use by AC (both heating and cooling) expressed as a ratio of battery charge used for EV drive. More AC use (higher AC load ratio on X-axis), less EV range (actual miles driven on EV mode on Y-axis) I got.

    Screenshot 2019-09-03 at 8.06.52 PM.png
     
    #55 Salamander_King, Sep 3, 2019
    Last edited: Sep 3, 2019
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  16. eveyo

    eveyo Junior Member

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    question for you guys. If you charge your battery to 100% and then drive in gas eco-mode do you see the battery percentage drop despite not being in EV mode? Is this due to normal battery charge degradation over time, use of AC or electronics? I ask this as I noticed this the other day. I fully charged to 100%. The next day as I drove just on gas mode and noticed the battery percentage drop to 95% and then as the day went on to 90%. Thanks
     
  17. Dael

    Dael Junior Member

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    They say to charge right before you use it. Otherwise not good for battery to be driving around in EV mode when battery is charged.
     
  18. Salamander_King

    Salamander_King Senior Member

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    That's perfectly normal. When you drive PRIME on HV mode with the traction battery fully charged, for the first few minutes of engine warm-up ICE is not providing sufficient energy and depletes traction battery charge. Losing ~5% of battery charge on HV mode is normal. If your drive is too short, you will not gain back that lost charge. However, if your HV drive is a longer one you can usually regenerate most of the used battery charge, sometimes all the way back to 100%. I do this often enough when I charge my car full with the intention of saving the charge for my destination. Start a car with 100% charge on HV, lose some battery charge, but during the trip, I can gain back lost charge.
     
    #58 Salamander_King, Sep 4, 2019
    Last edited: Sep 4, 2019
  19. jerrymildred

    jerrymildred Senior Member

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    That's why we keep telling newbies, "Just drive it." It doesn't get any more user friendly than that. No one HAS to experiment. And very few people do. They just drive it. That's what I do 99.99% of the time.
     
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  20. drash

    drash Senior Member

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    The Avalon Hybrid like my wife’s NX300H always runs the A/C (or heat) off of the traction battery. That way if you are sitting at a light and the ICE turns off you’ll still have A/C. You won’t see the impact unless you’re creeping along on EV only. You might see the ICE power divert more to the battery if you watch the power flow on the display but the ICE is normally on most of the time in a hybrid like the Avalon or NX300h.


    Unsupervised!
     
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