Difference between Driving Modes

Discussion in 'Prime Main Forum (2017-Current)' started by Mooney Driver, Jun 26, 2021.

  1. Mooney Driver

    Mooney Driver New Member

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    Just brought a 2021 Prius Prime and was reading the owner's manual and was a bit confused as to the differences in the driving modes. What is the primary difference between EV Auto mode and regular HV mode? Also when driving all electric, do you choose the EV mode or EV Auto mode to get the best overall mileage results? Thanks in advance for your input. Regards Mooney Driver.
     
  2. schja01

    schja01 One of very few in Chicagoland

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    In Auto it will use HV for highway driving and EV for non-highway speeds until EV battery is exhausted then it switches to HV mode. Honestly I don’t know if it drops out of Auto when the EV battery is used up.
     
    #2 schja01, Jun 26, 2021
    Last edited: Jun 26, 2021
  3. rdgrimes

    rdgrimes Senior Member

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    The beauty of this system is that if you just do nothing it will take care of all that for you. The only compelling reason to mess with the mode is if you wish to force HV (or Charge) mode when you still have EV battery range available. Otherwise just drive it.
     
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  4. Mooney Driver

    Mooney Driver New Member

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    My 2021 Prime is still out at sea somewhere due to arrive shortly. I'm reading the manuals to get a better understanding of the mode settings for a plug-in. I currently drive a 2017 Prius that averages around 61 MPG after 51K miles driven. If I want to drive around "town" on all electric power, what would be the best drive mode setting to achieve optimum miles driven? I live in a fairly hilly area so there are plenty of ups and downs type driving that are not too steep but definitely noteworthy.
     
  5. Trollbait

    Trollbait It's a D&D thing

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    The Drive Modes are mostly just a remapping of the accelerator pedal. In Eco, you have to push further to get the same amount of power with Power and less pedal push. Normal is inbetween, and they all deliver the same maximum power with the pedal pushed all the way. Which works better just comes down to driver preference. So try them all out. Double check the manual, but putting the car in Eco might also put the A/C into an eco setting.

    The description of EV Auto makes it sound like the car will use EV with lower speeds and power needs, with the engine coming when more power is called for. In practice, it seems to depend on route and driver style, with the possibility of Toyota fine tuning the software over the years. Some driving in EV Auto have reported the engine never comes on until the grid charge is used up. Others do have the engine come on before then.

    That means you are just going to have to try different modes out. If you don't want to devote too much mental energy to efficiency while driving, EV Auto should be the best mode for you. Some can do better with manually choosing between EV and HV modes. Then if the trip is going to be within EV range, just leave it in EV mode.

    Oh, the tires need several thousand miles of wear before they reach their best rolling resistance. You've probably noticed the Prius got better fuel economy after some 'broken in' period than when it was brand new.
     
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  6. rdgrimes

    rdgrimes Senior Member

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    Just charge it and drive it. ECO mode will help minimize the energy impact of the HVAC system.
     
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  7. PiPLosAngeles

    PiPLosAngeles Senior Member

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    As will a good infrared blocking window tint in hot climates. Your HVAC will have to work much less to keep you comfortable. Tint need not be dark to block heat. Some are hard to notice.
     
  8. john1701a

    john1701a Prius Guru

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    That is incorrect. Auto engages HV at times of high demand, like while you are accelerating onto a highway. That's it. Once you get on the highway and settle to a consistent cruise, it will automatically revert back to EV.
     
  9. schja01

    schja01 One of very few in Chicagoland

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    I stand corrected.
     
  10. PT Guy

    PT Guy Senior Member

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    We drive in EV all the time with two exceptions--
    --I switch to HV when I want to warm the oil before an oil change.
    --I switch to EV-Auto on one route we drive that is hilly and beyond battery range. The system uses the engine up hill and saves the battery for the flat sections. We get slightly lower total gas consumption this way.

    My wife never switches it, and she's happy running the car her way.

    Mooney, on your hilly routes try EV-Auto. Set it and forget it; no need to switch when the terrain changes. Then try EV all the time. See which works best for your driving.
     
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  11. where_are_my_keys

    where_are_my_keys New Member

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    Do you happen to know if this would this be the mode to use if I'm renting a Prius Prime and need to return it with full charge?
     
  12. FuelMiser

    FuelMiser Senior Member

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    I believe Charge Mode will only fill it to 80%
     
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