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Switch between HV and EV Modes

Discussion in 'Prime Main Forum (2017-2022)' started by Sid786, May 3, 2018.

  1. Sid786

    Sid786 Active Member

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    Recently I have decided to extend my battery usage per charge, by only using the EV mode when moving the car from dead stop position, such as at traffic lights or stop signs. Once the car is in rhythm then I switch to HV mode. Does this process of switching back and forth between HV and EV modes during driving is OK, OR it is not recommended.
     
  2. priuscatprimeguy

    priuscatprimeguy Senior Member

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    it kinda defeats the purpose because while in HV mode it switches to EV
     
  3. Sid786

    Sid786 Active Member

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    Pure EV mode gives prime very good power, while in HV Mode I had to press the panel to floor to move and catch up to the surrounding traffic speed. In both case the car is in ECO Mode. Once the speed matches to the surroundings, I switch back to HV Mode.
     
  4. john1701a

    john1701a Prius Guru

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    I only use HV for longer drives on the highway; otherwise, it stays in EV mode.

    Since the engine shuts off while in HV anyway, there isn't really any reason not to just take advantage of EV. Even in the winter I've seen that as the better choice.
     
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  5. Tideland Prius

    Tideland Prius Moderator of the North
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    Why don't you just leave it in HV mode then? The EV portion of the HV mode is pretty generous before the engine kicks in. You're literally describing a regular Gen 4 Prius operation :)


    (also, yeah there's no harm switching back and forth but you're not achieving anything more than just leaving it in HV mode)
     
  6. a_gray_prius

    a_gray_prius Rare Non-Old-Blowhard Priuschat Member

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    He may be stressing the engine a (very) little more than if he had just started in HV mode since power is being taken to move the wheels when the engine is first activated.
     
  7. Sid786

    Sid786 Active Member

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    I live in an apartment, so I cannot charge regularly. Hence using EV Mode when most useful i.e., after a stop light, makes it easier to extend EV use.
     
  8. FuelMiser

    FuelMiser Senior Member

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    Try using Normal or Power throttle mode if you want better throttle response in HV drive mode. ECO throttle mode gives a very lazy pedal response.
     
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  9. Bob Comer

    Bob Comer Active Member

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    I switch between EV and HV a couple times a day and that's to use the EV on the slower parts of my commute and HV on the faster. It's just to optimize gas mileage.
     
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  10. Pizza Driver

    Pizza Driver Active Member

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    I too cannot charge at home, so I try to use EV mode only when I feel it will do the most good. I have had no problems switching between HV and EV mode, though on rare occasions the switch to HV mode can result in a noticeable "thunk".

    Although I generally don't switch to EV mode for starting from a stop sign, when I want some very hard acceleration, like accelerating from a stop up a hill while trying to merge into higher speed traffic (45 mph) I will switch over to EV. This allows me to put my foot down harder without having the ICE kick in. Then once up to speed I will switch back to HV.
     
  11. Sid786

    Sid786 Active Member

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    Excellent! I am exactly doing as you have described. So far I not noticed the "thunk" when switching, but I will closely monitor.

    Driving in ECO + HV mode is a real drag and I have couple of frustrated drivers cut me or show obscene gestures. It is best not to frustrate others, if I have an option to avoid it and hence EV mode. For Power mode or normal mode, I felt that the ICE is working way to hard as I can hear the growling noise from the engine, so I try to avoid those modes.
     
  12. WTig3ner

    WTig3ner Junior Member

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    I hate to sound as dumb as I actually am, but I find Toyota's use of "mode" confusing. My 18 Prime has a button for "Drive Mode," which gives me a three-way choice: Eco Mode, Normal Mode, and Power Mode. But then there are two other buttons, one apparently to switch between HV and EV, and the other for EV Eco. I have no idea how the three choices from the Drive Mode button relate to the three choices the other two buttons represent. I promise that I have RTFMed, but it doesn't explain it to me.
    I gather that when driving at steady high speed, "HV Mode" may be best, saving EV for slower driving and city streets. But is that "HV Mode" with the left-hand button's Eco, Normal, or Power Modes?
    Apart from my general confusion, the specific problem I'm interested in is this: I have a 65-mile commute to work. About 33 miles of it is open highway driving, so I take it I should be in "HV mode." That's a toggle switch, so I get that. But where should I have the "Drive Mode" set for best economy when in HV?

    Does this make any sense?
     
  13. Trollbait

    Trollbait It's a D&D thing

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    Yes, the use of mode for two different things can lead to confusion. Sounds like you have the HV and EV modes figured out.

    The Drive Modes are on many cars now; hybrid, non-hybrid, and plug in. For the most part, they change the throttle position map. Power will open up the throttle with less depression of the pedal. Eco requires the pedal to be depressed further to get the same amount of power out of the engine. Normal is some where in between. With the pedal pushed to the floor, they all get the maximum power out of the engine.

    Eco gets its name because it allows more nuanced control of the throttle at lower speeds. generally, a driver won't call for more power than they need with it, so fuel isn't wasted by overshooting the pedal position you want. But which one gets the best fuel economy depends on what the driver is comfortable. You might not like having to press the pedal further with Eco, for instance. So just try them out on your drive, and go with what works for you.
     
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  14. Tideland Prius

    Tideland Prius Moderator of the North
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    Yup your question makes sense. @Trollbait already touched on a few points.

    The Drive Modes (Eco/Normal/Power) are independent of EV/HV/EV Auto.

    Just to further Trollbait’s explanation, Eco mode also puts the climate control in Eco mode as well (you’ll see the “Eco Heat/Cool” light illuminated). You can toggle that setting on or off independently and of course if you prefer normal in Eco climate or Eco mode with normal climate operation, that’s totally up to you. The reason it automatically puts the climate control into Eco mode is because it assumes if you’re driving in Eco mode, you want to save as much energy as possible. Eco Heat/Cool will limit the amount of energy the climate control system uses so it may take longer to heat or cool. Turn off Eco Heat/Cool if you need rapid heating or cooling.


    As for the powertrain options (EV/HV/EV Auto), you will always start in EV mode if there’s charge left in the battery. This is good for low speed (say, anything less than 40mph). Anything about and consumption significantly increases.

    On your 65 mile commute, it does make sense to go into HV mode for the highway portion since the engine will be more efficient than the battery. I would manually switch to HV mode a few miles ahead of time (depending on outside temperature) to let the engine run its warm up cycle so that you can accelerate on the on ramp with the engine (rather than in EV mode). You can blend the EV or HV mode on either side of the highway portion depending on terrain and speed limit.
     
  15. WTig3ner

    WTig3ner Junior Member

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    My thanks to both of you. So Drive Mode merely controls how far one has to depress the accelerator, right? So if my right ankle remains flexible--always a question at my age--I should set Drive Mode to Eco and then use the center button to shift in and out of HV.

    This I think I can handle. Again, my thanks.
     
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  16. Tideland Prius

    Tideland Prius Moderator of the North
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    Mostly, yes.
     
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  17. PT Guy

    PT Guy Senior Member

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    Mode does not = mode. As noted above, Eco, Normal, Pwr just controls how much scoot you'll get from a partial push on the accelerator pedal. Floorboarded is the same in all "modes." The difference is in the part push. I like Normal all the time. The Mrs. likes Eco around town and Pwr on the highway where she can get a quick boost to get into a gap in traffic.

    Why fiddle with the engine modes? Put it in EV and keep your concentration on the road and the traffic. The system is smart. It'll switch when it wants to. There is one route we drive, beyond battery range, that is hilly in the first part, and EV-Auto saves us a little gas; it runs the engine on the uphill parts and battery elsewhere as long as there's battery capacity. I switch to EV-Auto at the start and don't mess with it again.
     
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  18. Salamander_King

    Salamander_King Senior Member

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    Switching EV and HV modes during the drive is fine. I have never come across any recommendation not to do that. I did it all the time when I was trying to maximize the EV range on a charge. That being said, if the aim is to "extend the battery usage per charge", then you should use the HV mode when moving the car from a dead stop to accelerate and on the uphill portion of the trip, and switch to EV mode once the car is in the coasting after reaching the speed and gliding downhill portion. I used this technique often enough when the gasoline price was cheaper than the electricity price.
     
  19. Henrik Helmers

    Henrik Helmers Active Member

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    You’re free to change these modes at any time. The car takes care of itself. I think what you are describing makes sense, HV mode is more efficient for constant high speed.

    In practice it is difficult to outsmart the system though. I have gotten best mileage so far when spending my effort managing the throttle. When I try to be clever with the modes I tend to perform worse. I am sure there is a way to come out ahead, but it eludes me.
     
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