MPG in Hybrid Mode

Discussion in 'Prime Technical Discussion' started by CEJ, May 13, 2019.

  1. CEJ

    CEJ Member

    Joined:
    May 13, 2019
    130
    42
    0
    Location:
    USA
    Vehicle:
    2019 Prius Prime
    Model:
    Plug-in Advanced
    But isn't it true that if the charge allocated in the battery for EV were used up, you would necessarily be in pure HV mode, and whatever replacement charge is needed would have to come from the other sources (generator, etc.)?
     
  2. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    82,295
    35,758
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    yes, once there is no wall charge, it becomes a regular prius, and the software manages the battery level of charge and discharge with propulsion assistance and regeneration.

    and according to jb above, i'm wrong about prime, so your loss of 10% is still unanswered.
     
  3. jb in NE

    jb in NE Senior Member

    Joined:
    Apr 13, 2018
    2,235
    1,553
    0
    Location:
    Nebraska
    Vehicle:
    2018 Prius Prime
    Model:
    Prime Premium
    When the traction battery gets to 0% indicated and the car runs in HV only, there are a few ways to get charge back in the traction battery.

    1. Use charge mode and have the engine charge it (up to 80%).

    2. Put the car in charge mode long enough to get a few percent into the traction battery, then you can go to EV mode on a downhill and use regenerative braking (B mode, for example) to recharge the traction battery. I've gotten up to 50% battery doing this in the mountains.

    3. Plug into external power source when parked.
     
  4. CEJ

    CEJ Member

    Joined:
    May 13, 2019
    130
    42
    0
    Location:
    USA
    Vehicle:
    2019 Prius Prime
    Model:
    Plug-in Advanced
    Just finished 52mi of driving (accumulation of several in-town trips of 10mi or less) in HV mode starting with the battery 100% charged. The percentage dropped to 80% as indicated by several of you and has stayed there (this is, of course, 80% of the charge energy allocated for EV). This jibes with the fact I started with 39 EV miles and ended up with 31. I have gotten 72mpg so far.
    Questions:
    1. How are some able to preserve 90% or more of the EV charge-energy while in HV?
    2. How is that 20% of EV charge-energy being used if nothing is turned on?
     
  5. Salamander_King

    Salamander_King Senior Member

    Joined:
    Nov 8, 2015
    4,197
    3,219
    0
    Location:
    New England
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Premium
    That's very strange. I just drove ~300 miles today mostly on highway. I needed to save EV range for in-city drive at the destination, so immediately after starting the car, I hit HV button. Drove most of ~300 miles on HV, but traction battery level never went below 96%. In fact, after on highway speed, the battery recharged back to the original 100%. No, I did not use any CHARGE mode. This recharge was all by itself presumably by regen. I had 99% of battery left when I was off the highway and switched to EV mode in the city.

    The pic showing 100% traction battery level remaining after 179.6miles HV drive on the highway today.

    IMG_20190521_165924.jpg
     
    #65 Salamander_King, May 21, 2019
    Last edited: May 21, 2019
    jb in NE likes this.
  6. jb in NE

    jb in NE Senior Member

    Joined:
    Apr 13, 2018
    2,235
    1,553
    0
    Location:
    Nebraska
    Vehicle:
    2018 Prius Prime
    Model:
    Prime Premium
    That matches what I saw recently on a long trip. In HV mode, the battery stayed within a percent or two of when I started.
     
    Salamander_King likes this.
  7. Salamander_King

    Salamander_King Senior Member

    Joined:
    Nov 8, 2015
    4,197
    3,219
    0
    Location:
    New England
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Premium
    As @bisco pointed out, immediately after starting the car if you push on HV, some traction battery is used until warm-up is complete. I saw an initial loss of 4% after driving a short distance. I recovered this initial loss as soon as the engine warmed up and driving at highway speed. I guess, like OP, if all you are doing is a short distance drive, you may not recover this loss.
     
  8. CEJ

    CEJ Member

    Joined:
    May 13, 2019
    130
    42
    0
    Location:
    USA
    Vehicle:
    2019 Prius Prime
    Model:
    Plug-in Advanced
    So it might be the shorter trips (each requiring an engine warmup) and the slower in-town speed could be an explanation. I will be going on a 200mi trip in week or so and will be able to see if those conditions make a difference. Does anyone know where that 80% figure, which has been mentioned several times, comes from?
     
  9. Salamander_King

    Salamander_King Senior Member

    Joined:
    Nov 8, 2015
    4,197
    3,219
    0
    Location:
    New England
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Premium
    80% comes from a single quote I cited earlier on my comment #30. I have never seen my traction battery level decrease down to that level by just driving on HV. One thing I can think of the significance of 80% is that it is the level of traction battery that CHARGE mode can replenish from ICE. It is conceivable that there is a limit on how much ICE can recharge even without going into CHARGE mode, although I have not seen that happens to my PRIME. Beside short trip, excessive use of AC may also cause the loss. Also, I have not tested retention of traction battery charge over a long period, say more than a few days.
     
  10. CEJ

    CEJ Member

    Joined:
    May 13, 2019
    130
    42
    0
    Location:
    USA
    Vehicle:
    2019 Prius Prime
    Model:
    Plug-in Advanced
    I have now driven over 70 miles in HV mode and the EV charge continues to drop--now in the 60 percent range. I consulted TCS and the story I get there is that, yes, EV charge is being used in HV mode to make it more efficient and there is no limit to how much it will use. This makes some sense since I getting average mpg near 75, when I would have expected to be in the 50's. The acid test, of course, will be to see what happens when the charge is 0%. But, if this is true, doesn't it mean that the 2019 is different from earlier ones, who like SK are essentially maintaining full charge in HV mode?

    So it looks like I can't save charge to use in EV mode at the end of a trip. Does it make economic sense, in this case, to go into charge mode before I reach my destination, which I guess is capable of getting it back up to 80%?

    Thoughts?
     
    kevin.c likes this.
  11. jb in NE

    jb in NE Senior Member

    Joined:
    Apr 13, 2018
    2,235
    1,553
    0
    Location:
    Nebraska
    Vehicle:
    2018 Prius Prime
    Model:
    Prime Premium
    If this is a change for the model year, it's a change for the worse. I like being able to control how much battery I have in reserve.

    This in the 2018 owner manual, page 84 under the description of HV mode:

    "When the accelerator pedal is depressed heavily, drive force from both the gasoline engine and the electric motor (traction motor) is used to accelerate."

    You haven't been lead-footing it have you?
     
    #71 jb in NE, May 22, 2019
    Last edited: May 22, 2019
  12. CEJ

    CEJ Member

    Joined:
    May 13, 2019
    130
    42
    0
    Location:
    USA
    Vehicle:
    2019 Prius Prime
    Model:
    Plug-in Advanced
    No, definitely not a lead-footer. I suspect this new feature (if that is what it is) will produce greater energy savings, always a goal for the manufacturers.
     
  13. jb in NE

    jb in NE Senior Member

    Joined:
    Apr 13, 2018
    2,235
    1,553
    0
    Location:
    Nebraska
    Vehicle:
    2018 Prius Prime
    Model:
    Prime Premium
    Perhaps, but maybe some other 2019 or 2020 owners can report if they are seeing the same thing.
     
  14. CEJ

    CEJ Member

    Joined:
    May 13, 2019
    130
    42
    0
    Location:
    USA
    Vehicle:
    2019 Prius Prime
    Model:
    Plug-in Advanced
    Yeah, I would to love to know if any others have gotten this and have this confirmed . Doubt there are any 20’s yet. The 19’s were not available here until a few months ago and in short supply. Haven’t found anything in the owner’s manual about this.
     
  15. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    82,295
    35,758
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    this happened with pip. seems driving conditions had something to do with it.
     
  16. CEJ

    CEJ Member

    Joined:
    May 13, 2019
    130
    42
    0
    Location:
    USA
    Vehicle:
    2019 Prius Prime
    Model:
    Plug-in Advanced
    Can't resist asking, but, of course, you don't have to answer. By any chance does the NE stand for Nebraska?
     
  17. jb in NE

    jb in NE Senior Member

    Joined:
    Apr 13, 2018
    2,235
    1,553
    0
    Location:
    Nebraska
    Vehicle:
    2018 Prius Prime
    Model:
    Prime Premium
    Yes.
     
  18. CEJ

    CEJ Member

    Joined:
    May 13, 2019
    130
    42
    0
    Location:
    USA
    Vehicle:
    2019 Prius Prime
    Model:
    Plug-in Advanced
    What town? We may be neighbors!
     
  19. jb in NE

    jb in NE Senior Member

    Joined:
    Apr 13, 2018
    2,235
    1,553
    0
    Location:
    Nebraska
    Vehicle:
    2018 Prius Prime
    Model:
    Prime Premium
    Outside of Omaha.
     
  20. CEJ

    CEJ Member

    Joined:
    May 13, 2019
    130
    42
    0
    Location:
    USA
    Vehicle:
    2019 Prius Prime
    Model:
    Plug-in Advanced
    East side of Lincoln. Pretty darn close for a random cyberspace encounter. Am I right that you have a 2018 Prime and that you are able to retain most of the EV charge when you are driving in HV mode?
     
Loading...