How Hard to Brake

Discussion in 'Gen 3 Prius Main Forum' started by Yaesu, Nov 12, 2017.

  1. Yaesu

    Yaesu Junior Member

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    When braking, is there any fuel economy benefit when braking harder than when the braking gauge shows full? There are times when I could choose to brake gently for a long distance but would rather coast longer then brake harder then maximum on the gauge as I approach the stop. I understand that a very hard braking action will use the calipers.
     
  2. bisco

    bisco cookie crumbler

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    try to keep your speed and following distances in a place where as little braking as possible is needed (outside of emergency situations) until your down to 6 mph, when manual braking takes over completely from regen.
     
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  3. WilDavis

    WilDavis Senior Member

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    By looking ahead at the traffic situation, brake-lights, traffic flow etc. I try to drive with only minimal use of the brakes, since it really helps to stretch the gas mileage! Back when I lived in the UK, I drove a Bond-Bug¹, and in those days (mid 1970s) I did all my own maintenance, and one weekend I'd decided to drive home from Oxford to North Devon to visit my parents, and I'd also started to do a brake-overhaul on the Bug, so I started the brake-job, but unfortunately needed a part, ran out of time , and was unable to completely finish the job, so I drove nearly 200 miles (in the dead of night) without using the brakes (well the hand-brake worked), of course it would have been easier (and more efficient) if I'd been driving a Prius! ;)

    ¹ Bond Bug - Wikipedia

    ¹ WHD's Bond Bug
     
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  4. Yaesu

    Yaesu Junior Member

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    I don't think I am making myself clear. I understand that not using the brake is best for obtaining high fuel mileage. But my question is, does the brake regenerative system provide electrical power beyond the limit of the braking power indicator on the display. I ask this, because the display moves to its maximum limit with relatively little brake pressure.
     
  5. bisco

    bisco cookie crumbler

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    braking is a constant mix of regen and calipers, except under 6 mph. if you hook up a scan gauge, you will see the calipers starting to operate along with the regen. the percentage mix starts in regents favor, and ends in calipers favor.
     
  6. Yaesu

    Yaesu Junior Member

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    I have a standard Scangauge in the RV. Are you saying that it will show me regen/caliper braking? If so, I will connect it to the Prius.
     
  7. bisco

    bisco cookie crumbler

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    that is what i have read in other threads.
     
  8. Maarten28

    Maarten28 Active Member

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    No, it does not regenerate more if you brake harder past the point when you get the maximum regeneration.
    BTW: the maximum regeneration may be lower than normal when the battery pack is cold.
     
  9. fuzzy1

    fuzzy1 Senior Member

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    Nope, it doesn't.

    The max limit will also vary with speed. The faster the car is moving, the easier you hit the limit. As the car slows, the max regen limit shifts to somewhat harder braking, but never gets anywhere close to full panic or emergency braking levels.

    This is a direct consequence of basic physics equations. The electrical limit of regeneration is about 26 or 27 kW, if the battery isn't restricted by temperatures limits. Full force highway speed mechanical braking is over 500 kW, far beyond the car's electrical limit.
     
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  10. Yaesu

    Yaesu Junior Member

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    Thanks for the responses. I suspected that keeping the braking regenerative power at the upper edge of the indicator was the best that could be done when using the brakes for slowing.
     
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