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How to read the consumption chart?

Discussion in 'Gen 3 Prius Main Forum' started by Lunchbox, Mar 5, 2011.

  1. Lunchbox

    Lunchbox Junior Member

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    Sorry for being a little bit dumb here =) In the 5-min consumption chart, I know the BAR means MPG, but what about those little car icons within the bar?
     
  2. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    They represent energy recovered via braking. They show that you are not just throwing away that energy. You want as few as possible, (it is better to avoid braking at all) but you can be happy that when needed, you got some energy back.
     
  3. revhigh

    revhigh MPG Enthusiast

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    They indicate 'recovered' voltage. I'm not sure exactly how much each car represents, but I'm pretty sure that you get them by regenerative braking or coasting.

    I'm sure someone else can explain it better, but that;s the gist of it.

    Looks like Jimbo and I responded at the same time ! :D

    REV
     
  4. Lunchbox

    Lunchbox Junior Member

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  5. macman408

    macman408 Electron Guidance Counselor

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    When going down a long hill or mountain, you have lots of extra energy that you can store in the battery. Having lots of regen is only a bad thing if it means that you have to run the engine a lot to get it (eg to accelerate back up to speed after you stopped at a stoplight). When it comes "for free" like down a hill, it's good. Well, ignoring the fact that you had to run the engine a whole lot to get up the hill in the first place, of course - overall, it's still a net loss. But you can't do anything about the terrain, and you can at least do a tiny bit to anticipate all your stops.
     
  6. Skoorbmax

    Skoorbmax Senior Member

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    It says right on that screen that each car represents 50wh. Thus 20 of them equal one megawatt or about $.10. However, using that math projected out over an hour it seems that regen would be responsible for virtually no gas savings at all (because generally each 5 min bar will have 1-3 of these, the max is 8 I think but I've only seen that once after riding the brake basically down a mountain. Can anybody reconcile these numbers?
     
  7. Prius O Matic

    Prius O Matic Junior Member

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    I think my display shows each car represents 30 watt hours.

    Getting my glasses and heading for the car. ;)
     
  8. Prius O Matic

    Prius O Matic Junior Member

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    Yup... =30wh.

    This is on a 2011. Is that really different on the 2010, or are you like me and occasionally forget your glasses? :D
     
  9. Paul58

    Paul58 Mileage Miser

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    I thought the display on my 2010 said 50wh as well, I may have to take a closer look. Of course, that 50wh on the 2010 may be a generous estimate, kind of like the average mpg reading! The lawyers may have made them change it for liability purposes, i.e. someone suing Toyota because they weren't actually recovering 50whs per little car displayed!
     
  10. Prius O Matic

    Prius O Matic Junior Member

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    Actually Paul it seems we are both correct. I looked after leaving this morning and if you have it set for 1 minute updates it states =30wh. However, if it is set for 5 minute updates then....you guessed it....50wh.

    Hi five! Both right. (I've had too much coffee today me thinks)
     
  11. Steve23

    Steve23 New Member

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    Correction. 20 of them would be one killowatt-hour (KWH). 1 MHW=1000KWH. Additionally, A watthour (and also KWH and MWH) is a finite unit of energy. This confuses most people because a Watt is actually already a rate of energy flow which is then called power. One watt is one Joule per Second flow.
    So when we want to totalize this power flow over a period of time we end up calling them watt-hours. The hours and the time part of the rate implicit in the definition of a watt cancel out and you end up with energy. One KW = 1.34 horsepower. The electric motor in my 2011 Prius is 60KW or 80.4 Horsepower. (max of course).

    Clear as mud?

    As far as gas savings, I think a large part of it is that the engine is not running in addition to the power generated. Regular cars do a lot of idling that this car does not do.

    Steve D