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When does regenerative braking kick in?

Discussion in 'Prius v Main Forum' started by BluePriusVee, May 5, 2013.

  1. BluePriusVee

    BluePriusVee Junior Member

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    Hi folks,

    Just bought my first Prius five days back, and all I've been doing ever since is read up on the fascinating details of how a Prius works :) One thing that I'm still a bit unsure of is when exactly does regenerative braking kick in? Is it as soon as I take my foot off the gas pedal? Or after I slightly press the brake pedal? What's the best practice in this regard?

    Thanks!
     
  2. Feri

    Feri Active Member

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    As soon as you take your foot off. Even more if you brake.
     
  3. Les_PL

    Les_PL Active Member

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    Then - the new question arises - when the hydraulic brakes kicks in? ;)
     
  4. css28

    css28 Senior Member

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    The hydraulic brakes definitely kick in when you're braking hard enough to fill the "regen" area of the HSI. Additionally they're always in play at very low speeds (below 7 mph or so, I think).

    The best practice for maximizing the regen is to brake early so you can brake gently (less than filling the regen zone).

    An even better practice is to learn the traffic light timing characteristics along your route so you can hit more of them on green. This is impossible in most cases when there are other drivers. Don't become a traffic hazard.
     
  5. The Electric Me

    The Electric Me Go Speed Go!

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    Correct me if I'm wrong.

    But you should notice that if you are coasting, with neither your foot on the brake, nor the accelerator, the charge area of the HSI is just barely filled. So some regeneration is happening without any application of the brakes at all.

    Then my understanding (which could be flawed or wrong) is that The Prius under "normal" non-emergency, or non-sudden braking, uses primarily regen braking. So long timed out, gradual braking gives you the best regeneration possible.

    The friction brakes are designed to basically take over when needed.
     
  6. Jzerocsk

    Jzerocsk Member

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    In addition to the above situations if ABS or traction/stability control are triggered, it will automatically kick the physical brakes on. You may notice this if you go over pothole or manhole cover while braking...the pedal feedback suddenly changes.
     
  7. Les_PL

    Les_PL Active Member

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    Yes - on the beginning it was confusing, even little scary - but now I'm getting to use to it :)
     
  8. BluePriusVee

    BluePriusVee Junior Member

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    Luckily I can use a route to/from work that has 10 miles city streets with mild traffic and 10 miles freeway. I tested the long gradual braking several times on the city streets and started to see vastly improved mileage already. Thanks for the replies everyone! Next stop would be to try pulse and glide. The first couple of attempts have been a total failure. I have only had a couple of occasions where it was gliding, i.e., with no arrows in any direction on the energy monitor, but they were too brief to be counted as gliding. Looks like this is a bit tough to master.
     
  9. jdenenberg

    jdenenberg EE Professor

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    The above information is correct as long as you are in "Drive". In "Neutral", regenerative braking is disabled. This can be useful as lightly braking in neutral will clean surface rust off your brake rotors.

    JeffD