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Anonymous asked in Cars & TransportationMaintenance & Repairs · 4 years ago

What is the point of regenerative breaking in cars? Why isn't it just regenerative moving?

Why do they only generate electricity when you're slowing down? Isn't that highly inefficient? doesn't that defeat the purpose of generating electricity in the first place?

If you have a container of liquid draining at a gallon a minute, and you wanted to keep it full, would you rather add a few cups here and there, or have a constant stream of a quart a minute?

Why don't we just have regenerative moving? the cup would drain much slower with some energy being constantly put back in as opposed to a surge of energy here and there.

4 Answers

  • Anonymous
    4 years ago
    Favorite Answer

    You are recapturing the energy of the moving vehicle as you slow it down.

    In a hybrid the computer can switch to generator mode, and use the momentum of the car to recharge the battery. Rather than using conventional brakes, where that energy is just going to go into heating the brakes. The power is then stored in the battery and can be used to accelerate the car again.

    It's not a totally efficient, but because all the hardware is in place anyway in a hybrid or electric car, then why not do it, and gain a little more range.

    If you try and generate power while moving, you create more load on the vehicle, and it takes even more energy to keep you moving, which defeats the purpose.

    In old friend of mine was a railway mechanic, and once told me that the electric trains he worked on could recover about 50% of the power they used through regenerative braking as they went downhill or slowed down. So the first part of the trip uphill they where drawing power from the grid, then going down the other side of the hills they where actually generating a significant amount of power back into the national grid.

    • FlagMichael
      Lv 7
      4 years agoReport

      Regenerative braking also does wonders for brake life. My 2002 Prius, at 184K miles, is on the original brakes.

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  • 4 years ago

    Regen braking harvests the otherwise wasted energy of a decellerating vehicle by engaging a generator which recharges the batteries. If it was used all the time, the batteries would draw too much engine power and use more fuel. You can't get more energy out of a system than you put in, only change it's state, with losses along the way.

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  • Jay P
    Lv 7
    4 years ago

    It's BRAKING, not "breaking".

    A regenerative brake is an energy recovery mechanism which slows a vehicle by converting its kinetic energy into a form which can be either used immediately or stored until needed. To capture that energy while driving normally means placing an increasing load or drag on the energy which means more fuel used.

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  • Anonymous
    4 years ago

    That's easy the capacitor which stores its energy would only be able to store a certain amount of energy to release it. The technology is simply not there yet. The car industry knows nothing about the polarity of neg and positive. They don't know how to convert positive energy into negative energy effectively. Regenerative breaking is storing positive energy which will be released anyways as positive energy via the size of the capacitor. The capacitor can only store the amount the battery of the car stores. It is possible, for negative-to-positive to be created via a surge coil and/or pulse circuit. Positive can infact overtake negative, and energy can infact go in two directions.

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