Will I go blind if I abuse my B too much?

Discussion in 'Gen 3 Prius Main Forum' started by Kevfra, Jun 18, 2018.

  1. Kevfra

    Kevfra New Member

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    I live in the mountains where there is no such thing as a straight road or a level road. It isn't unusual to coast for several miles downhill, several times a day. Consequently I use the 'B' mode for braking to save my actual brakes, just as I shift down in a conventional car.

    Sometimes that B mode really winds up the revs when I'm really on a steep decline. Has anyone ever heard of B mode excessive use causing problems over time?
     
  2. fuzzy1

    fuzzy1 Senior Member

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    I haven't heard of such a problem.

    The frequent high RPM will cause extra engine wear, but I take that as an inherent consequence of being in mountainous areas. If you don't want to walk the route, and don't want to move to a flatter area, then this is just what you must do.
     
  3. ForestBeekeeper

    ForestBeekeeper Active Member

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    I have gotten into the habit of using 'B' a lot. My thinking behind this is to save on brake wear.

    I had thought that light braking was supposed to use the 'regenerative' function. Which in theory would not wear on the brakes. But after about 120k miles my brake pads had to be replaced. So I am not entirely sure that the 'regenerative' function truly does anything.

    I think that using 'B' seems to extend the life on my brake pads. [if nothing else]
     
  4. sam spade 2

    sam spade 2 Senior Member

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    That is NOT a problem.
    A lot of people would love to go that long between brake pad changes.

    (Prius owners do a fantastic job of worrying about insignificant stuff.)

    And for the OP, in my experience when the rev's sound like they are getting a bit high your speed is probably a bit high too.
    Use the brakes for a few seconds to slow it down just a bit and unless the grade is REALLY steep it might hold that lower setting.
     
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  5. jjmerp

    jjmerp Junior Member

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    It will also over rev when the battery is fully charged and have no regen assist

    Posted via the PriusChat mobile app.
     
  6. Johnny Cakes

    Johnny Cakes Active Member

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    Love the title for the thread. :)
     
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  7. Mendel Leisk

    Mendel Leisk Senior Member

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    I would only use B where the battery's getting COMPLETELY full and you still have a goodly steep downhill distance to go. Shorter downhills, you're not saving your brakes, and needlessly reducing charging.
     
  8. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    The computers will not let the engine over rev. I have not seen over 4700 RPM in B, red line is 5200 RPM on Gen 3 and v.
    I would use B from the summit if you know that the battery will fill before the bottom, over 600 foot drop. (3000 foot drop for PHEV)
     
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  9. phoenixgreg

    phoenixgreg Senior member

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    Another option is to let your cruise control do the work. Depending on the slope, set the cruise for a speed you are comfortable with and it will automatically "B" to maintain the speed you have set.
     
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  10. Mendel Leisk

    Mendel Leisk Senior Member

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    Should qualify that: it's better to make the shift to B at the top of the hill, requires a judgement call.
     
  11. sam spade 2

    sam spade 2 Senior Member

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    THANK YOU. I was going to say that too but then got distracted.

    I think that the max. engine braking might cut in a bit later in cruise so a little braking might still be necessary.
     
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  12. qdllc

    qdllc Senior Member

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    Blind? No. Hair on palms? Definitely.
     
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  13. Isaac Zachary

    Isaac Zachary Member

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    After years of driving commercially, yes, I downshift in whatever vehicle I'm in. Have you ever been in a vehicle suffering from brake fade on a long steep decent? I have, I was not the driver, and now if someone refuses to engine brake I ask for them to pull over and let me walk myself down off the mountain, thank you very much! I have to climb and descend some 10,000ft or more daily in my car. But never have I had a vehicle that needed its brakes changed even after some 200,000 miles or more of driving, including the buses I drove over many mountainous passes.
     
  14. mjoo

    mjoo Senior Member

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    You'll poke your eye out, kid...

    Pixel XL ?
     
  15. bentbow

    bentbow Junior Member

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    arent you endangering the expensive engine at the cost of cheap brakes?
     
  16. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    The computers will not let you abuse the engine. Although it sometimes sounds like it.

    Engine = $1500

    HV Battery (regen braking) = $3000


    On some other car, the brakes might be cheap.
     
  17. Grit

    Grit Senior Member

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    technical question: If engine braking is engaged, and you press down on the brake pedal in combination, is there any regen happening as you press brake pedal down?
     
  18. fuzzy1

    fuzzy1 Senior Member

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    If the battery isn't full, then there is some regen happening.
     
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