B mode: What is the advantage to use B mode when driving, more regeneration? more economy?

Discussion in 'Prime Technical Discussion' started by Gaëtan Lafrance, Jul 5, 2018.

  1. Pdog808

    Pdog808 Active Member

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    Yeah I have to admit being a bit of a control freak when it comes to maximizing miles per tank of gas (about 950+ miles per tank on the average).

    I manually move between EV and HV and never use EV-Auto. My daily drive is about 18.5 miles one way and I'm able to get about 100 MPG by charging about 3 times per week.

    I try to use EV only at lower speeds (below 40 MPH preferred) and switch to HV when I know I'll be going 50+ for at least 5-10 miles. Remember, electric motors drop have a severe dropoff in efficiency above about 25-30 MPH or so.

    PS - yes this thread can probably go on to at least 50 posts or more.
     
  2. fuzzy1

    fuzzy1 Senior Member

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    I'm inclined to believe that 'brain-dead' and 'just their DRLs' are two sides of the same coin.
     
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  3. triggerhappy007

    triggerhappy007 Active Member

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    Most newer cars now have lighted display in the daytime. So in the dark they will think their lights are on since the DRL are bright and their gauge is lighted.
     
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  4. Tideland Prius

    Tideland Prius Moderator of the North
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    Annoying as heck. People can't even take the time to read the owner's manual or the salesman couldn't be bothered to show them all the new features and ensure that their customer leaves the dealership understanding the vehicle. For my cars, the salesman (sorry product specialist) did go through the basics.

    Canada is introducing a law to counter that but it won't be in effect until 2023. (or at least, manufacturers have until 2023 to figure out which 1 of 3 options they want to implement).
     
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  5. Gaëtan Lafrance

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    Thanks so lot for this precision

    Merci beaucoup pour cette précision.
     
  6. akbetts

    akbetts Junior Member

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  7. akbetts

    akbetts Junior Member

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    The main advantage I have found of the B mode in Vermont is going downhill on steep snow covered roads in winter. In the B mode you dont need the foot on the brake, and the computer controlled braking and traction control keeps the car at a safe low speed in a straight line.
     
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  8. jerrymildred

    jerrymildred Senior Member

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    That's pretty much what it's for. (y)

    Using it on flat ground to supposedly increase regeneration is silly. You can get the same regen with the brake pedal, which you'll need to use anyway if you plan to stop.
     
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  9. padroo

    padroo Senior Member

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    I use it in stop and go traffic so I don't have to keep tapping my brakes. Kind of like driving a stick shift, it will slow down and not coast.
     
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  10. Old Bear

    Old Bear Senior Member

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    That's been my experience in stop-and-go city driving. One still has to use the brake pedal to come to a complete stop, but otherwise "B" mode allows a very comfortable driving experience when constantly going from 2 mph to 20 mph and back.

    Interestingly, I recall learning that back in the days of manual transmission cars, city taxi drivers would just leave their gear box in "second" and not bother shifting when in heavy traffic. It probably was no worse on their clutch than going between "first" and "second." I'm sure their clutches did not last very long in that kind of service under any circumstances.
     
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  11. stevepea

    stevepea Senior Member

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    I just drove 28 miles roundtrip city driving yesterday and got 6.8kw/hr using B. Roundtrip (about 14miles each way). Level driving along city streets on a Saturday, all in B, as is my default for city or start-and-stop driving. Looking back at my readings for days where I don't use freeway it's usually in the high 5s (5.4-5.8 typically, using B), though it sometimes goes to the mid 6s, or occasionally down to 5.0, but if it's just street driving in EV "B", mid to high "5s" is the norm. I was going to snap a picture of the readout but didn't bother...
     
  12. axle2152

    axle2152 Active Member

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    I'll throw in my impressions so far. I previously had a 2016 Prius Two and traded it in for the Prime Plus. One thing for sure is that the regenerative braking is much more robust than on the 2016...I haven't plugged my scanner in to see just how much current is going back into the battery but I can say that going down several miles of 6-9% grades can regenerate somewhere around 3 kWh of charge and I never had to use B yet in the Prime. The regeneration is stout enough to keep the speed under control without using the brakes. Unless you're going down a very steep grade you probably won't need B at all.
     
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  13. jerrymildred

    jerrymildred Senior Member

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    Same thing but on a smaller scale with my PiP. I finally got to drive it in the mountains last month and was IMPRESSED!
     
  14. utsug

    utsug Active Member

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    Another advantage of using "B" is save your brake pads.
     
  15. Starship16

    Starship16 Senior Member

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    Thanks. I will have to try that sometime.
     
  16. jerrymildred

    jerrymildred Senior Member

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    Where did you get that notion? Using B mode does nothing to save brake pads. Brake pads come into play when you call for more braking force than can be applied with regeneration. Whether you're in D or B makes no difference. Please read the manual.
     
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  17. utsug

    utsug Active Member

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    Oh I thought its like an engine brake. :D
    Thanks for clarifying it.
     
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  18. jerrymildred

    jerrymildred Senior Member

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    Remember that when you regenerate, not all of that deceleration energy goes back to the battery. Some of it is lost in heat in the wires and MGs. The higher the regen, the higher the current. The higher the current, the higher the heat loss. If traffic allows, it's more efficient to decelerate more gradually by allowing more following distance.
     
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  19. jerrymildred

    jerrymildred Senior Member

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    B mode works differently in HV mode vs EV mode, I discovered. Also the plug in cars act a little differently than the others. So a full explanation gets pretty lengthy. There may already be one here on the forum, but I don't have time to look for it now. If there isn't one, we should probably generate one because this is a confusing topic and understandably so.
     
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  20. jerrymildred

    jerrymildred Senior Member

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    I forgot to say that yes, it often is an engine brake, but not always. ;)
     
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