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Regenerative Braking

Discussion in 'Gen 2 Prius Main Forum' started by Kaos1, Feb 8, 2006.

  1. Kaos1

    Kaos1 Junior Member

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    Greetings,

    I'm a new Prius owner, 06/06 seaside pearl, and learning much about the car. I've searched a bit to learn about the "B" setting in the transmission and there is much discussion about it. It seems that it is better to brake then to use the "B" to store charge when stopping.

    The question that I bring is about the regenerative braking. How can you tell when you've pushed the brake hard enough to actually engage the brake pads? If I listen closely, I think that I can hear a very high pitch whine of the generator when lightly depressing the brake pedal. I can't ascertain at what point the wheel brakes take over.

    I know that the most efficient travel is not to use the brakes at all. Every time you change the form of energy, you loose some to inefficiencies in the system. Kinetic to electric back to kinetic. If I'm going to harvest the most electrons in the process of stopping, I would like to exercise control and make more charge and heat the disks less.

    Any advice?

    Kaos1
    first full tank 49 mpg (computer) / 48 mpg (calculated)
     
    #1 Kaos1, Feb 8, 2006
  2. V8Cobrakid

    V8Cobrakid Green Handyman

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    a very light braking. You can gain back two bars if not more if you do it right. Just barely touch the brake.. you shouldn't really feel it "grab" just start to slow down.. so.. yeah.. very light braking.. very steady light braking. let the brake do it's job.. just make it take a couple hundred feet.
     
    #2 V8Cobrakid, Feb 8, 2006
  3. TheForce

    TheForce Stop War! Lets Rave! Make Love!

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    I have my Prius for a little over a month now and I cant tell when it kicks in but I have noticed that when I get to about 5mph or less I can hear the breaks kick in with its scraping sound. I have always pressed lightly on the break so I dont know if the breaks kicked in before that or not. I hope that noise is normal.
     
    #3 TheForce, Feb 8, 2006
  4. efusco

    efusco Moderator Emeritus
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    You can actually brake quite firmly before the friction brakes kick in. The best way to "Know" is to train your foot to know how much pressure to put on.

    Here's how you know if you had only regen braking...at 7mph you will feel a 'drop out' of pressure on the brake pedal. Regen only goes down to 7mph where braking goes to friction only.

    Now, just experiment with steady braking pressure...very light at first so you're sure you feel the drop out. The start doing runs with steady braking at gradually more firm pressure each time until you notice that there is no longer any drop-out at 7mph.

    Be aware, there are other things that will prevent regen braking from going all the way to 7mph. If you hit a solid bump it sort of activates the ABS system and regen drops out...so make sure your experimentation is on a nice smooth road.
     
    #4 efusco, Feb 8, 2006
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