1. Attachments are working again! Check out this thread for more details and to report any other bugs.

How many green cars...

Discussion in 'Gen 2 Prius Main Forum' started by Synergy, Sep 7, 2008.

  1. Synergy

    Synergy New Member

    Joined:
    May 27, 2008
    33
    0
    0
    Location:
    Ware, Massachussetts
    Vehicle:
    2008 Prius
    Hi all.
    I just got my prius last week and im loving it! I have kind of a "silly" question though, but here goes. How many green cars does it take to charge the battery one bar. Say if I get 3 green cars from regenerative braking does that even equal a bar on the battery, or does it take 5 green cars?

    Oh and im thinking about putting mud flaps on my prius. Would you recomend it? Or are they not worth it? And any other accessories that you have that you couldn't live without (I allready have a heat shield for the front window)

    Thanks!

    Synergy
     
  2. qbee42

    qbee42 My other car is a boat

    Joined:
    Mar 2, 2006
    18,058
    3,073
    7
    Location:
    Northern Michigan
    Vehicle:
    2006 Prius
    It's not that simple. The battery bars do not represent even units of energy, whereas the green cars do. Other factors also come into play, such as temperature and the age of your battery, which both affect the ability of your battery to accept charge.

    Tom
     
  3. Rokeby

    Rokeby Member

    Joined:
    Jan 21, 2008
    3,033
    708
    75
    Location:
    Ballamer, Merlin
    Vehicle:
    2008 Prius
    Synergy,

    'Twould be best to ignore the Leaf Cars. At best they are Reality Reminders,
    more likely they are Tokens of Failure.

    How so?

    Ultimately, all movement of the car comes from using gas from the tank.

    Reality Reminders result from scavenging small amounts of energy when
    you have to slow down to accomodate the real world in which you drive:
    stop lights/signs, incoming traffic, a really steep hill -- remember you
    already have or will have to climb the upside of that hill trading gas,
    chemical energy, for potential energy which can only be fully realized by
    rolling unimpeded down the hill, and on, and on until you roll to a stop.

    Tokens of Failure occur when you have to slow dow due to misjudging time,
    speed, and distances. This is just another way to waste gas.

    Basically, you want to avoid creating the little Leaf Cars if you're after good
    FE/MPGs.
     
  4. Freedom

    Freedom Active Member

    Joined:
    Jun 22, 2008
    531
    65
    0
    Location:
    Northeastern MA
    Vehicle:
    2008 Prius
    Model:
    Three
    Hi Synergy!

    I have lived in New England all my life. I can't imagine NOT having mud guards on a car in our climate. I bought them on ebay from Dick Dyer Toyota (best price) and put them on myself. You are a bit north of me (I'm in RI), but we get so much 'slush' kicking up on our cars I think mud guards are a must have around here.

    The other item I insisted on was the LCD protector. You can buy it from Nushield. I have a touch screen video game, use the provided plastic pencil, and have seen what happens to a touch screen. :rolleyes: Wished I had put the protector on THAT screen sooner. True, you seldom ever need to touch the Prius screen, between the steering wheel buttons and the buttons along the side of the monitor, but I figured it was the safe route.
     
  5. donee

    donee New Member

    Joined:
    Aug 15, 2005
    2,956
    197
    0
    Location:
    Chicagoland
    Vehicle:
    2010 Prius
    Model:
    III
    Hi Synergy,

    I have additional instrumentation and the bars on the SOC MFD display are not too reliable. They have different switching points discharging, versus charging. And they are also unevenly spaced, as previously mentioned.

    But on average, here is a gross approximation. The green cars are 50 watt-hours, or .05 kilowatt-hours (kwh). The Prius battery is something like 3 kwh, but the bars only range from 40 to 80 % approximately, so that range is 40 % of 3 kwh, or 1.2 kwh. And there are 8 bars, so if you divide them up evenly (which we know is wrong, but just for the sake of discussion) that is .15 kwh. .15 / .05 is 3. You would need 3 green cars for the SOC to change about 1 bar.

    So, you made a good guess. But due to the uneven spacing, sometimes it will take 2 cars to change 1 bar, and sometimes 4.
     
  6. Bob64

    Bob64 Sapphire of the Blue Sky

    Joined:
    Apr 9, 2007
    1,540
    92
    0
    Location:
    Virginia
    Vehicle:
    2007 Prius
    Model:
    N/A
    Uhh... I think your math is a tad off donee (or mine is).

    2004+ Prius capacity = 6.5 Ah * 201.6V = 1.3 KWh
    1.3 KWh * 40% available (40%-80%) = 520wh available
    520wh available / 100 = 5.2 wh per % (or 18,720 joules per %).

    green leaf = 50wh
    each bar can be ~4%-14% "long"
    1% = 5.2wh
    9.6% = 1 green leaf

    So yes, it can equal one "Bar" or even two - depending on where on the chart it is. Just remember that each green leaf regenerates ~10% and you'll be fine.
     
  7. Synergy

    Synergy New Member

    Joined:
    May 27, 2008
    33
    0
    0
    Location:
    Ware, Massachussetts
    Vehicle:
    2008 Prius
    Wow guys, thanks for all of your responses.

    Freedom I will definatly invest in some mudflaps. They seem easy enough to install on my own, and my parents insisted on getting them. I thought about getting a screen-protector. Im always touching the screen. Maybe its because i just got the car and maybe I wont be switching as often but maybe i will, lol. Are you talking about a Nintendo DS, yep got one of those and bought a screen protector right away as I saw the damage the plastic pencil does to it after awhile by my friends DS.

    And thanks so much bob64 and donee for giving me a rough estimate. It was just out of curiosity. Where I live there are alot of long country roads with the speed limit around 40 so i dont see alot of green cars, which i guess is good!

    Regards.