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

Just how much power am I saving?

Discussion in 'Gen 2 Prius Main Forum' started by spim, Jul 10, 2004.

  1. spim

    spim New Member

    Joined:
    Jul 10, 2004
    2
    0
    0
    I've had my 2001 Prius for about a month now, and I've started to wonder, when I brake well and get a half or whole lightbulb on the Consumption montior, exactly how much energy am I saving? I mean I know its 50 Wh (watt-hours?) but to me that doesn't really mean anything.

    How does it translate to power saved for the car? I assume it would be the power needed to run a 50 Watt lightbulb for an hour, but I really don't know how many watts you need to make a car go 10 feet, or a mile, or whatever.

    Can anyone translate this into more human terms for me?

    Thanks
    -spim
     
    #1 spim, Jul 10, 2004
  2. NiMHPrius

    NiMHPrius New Member

    Joined:
    Jul 7, 2004
    33
    0
    0
    Location:
    S. Calaifornia USA
    On a flat road already cruising about 55 mph the Prius uses about 200Wh to go 1 mile (roughly). So 50Wh of energy recovered will give you approximately 1/4 mile of energy. Acceleration or going up hill can increase up to 10 times this 200Wh per mile consumption. About 40% of the kinetic energy of your Prius can be recovered when you are breaking. Why not higher? Well there is various resistances working on the car ( wind, rolling and mechanical friction, as well as battery charging, inverter and generator efficiency).

    All the numbers I just gave you are the best possible values. The way you drive and break as well as the terrain and air temperature have great affect on how much you consume as well as regenerate.

    Hope this helps.
     
    #2 NiMHPrius, Jul 10, 2004
  3. spim

    spim New Member

    Joined:
    Jul 10, 2004
    2
    0
    0
    That sounds pretty reasonable, thanks for the answer.
     
    #3 spim, Jul 11, 2004
  4. richard schumacher

    richard schumacher shortbus driver

    Joined:
    Mar 27, 2004
    7,663
    1,038
    0
    Location:
    United States
    Vehicle:
    2004 Prius
    Model:
    N/A
    In round numbers the Prius uses roughly 100,000 Watts at maximum aceleration. (That's roughly the power sucked on average by 100 suburban houses. It's a pity that there's no safe and easy way of connecting such a power plant to a house for emergency use. )

    If the Prius accelerates at that power for the 10 seconds or so it takes to reach 65 MPH, that's one million Joules or about 280 Watt-hours of energy. Thus one green car in the display represents about 18% of the energy needed to come to highway speed from a stop.
     
    #4 richard schumacher, Jul 12, 2004
  5. efusco

    efusco Moderator Emeritus
    Staff Member

    Joined:
    Nov 26, 2003
    19,891
    1,191
    9
    Location:
    Nixa, MO
    Vehicle:
    2004 Prius
    Model:
    N/A
    More numbers to throw around. It's estimated that energy recovered through regenerative braking improves fuel efficiency b/w 2-4% depending on the driver, conditions, etc. Not a lot, but another little piece of the the puzzle.
     
    #5 efusco, Jul 12, 2004
(You must log in or sign up to post here.)