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

REGEN % and accessory loads

Discussion in 'Gen 2 Prius Technical Discussion' started by djm74, Nov 9, 2006.

  1. djm74

    djm74 New Member

    Joined:
    Nov 9, 2006
    2
    0
    0
    I am hoping someone has info/data on what % of the Prius's kinetic energy can be regenerated on average. I know it varies quite a bit based on battery level, grade, etc, but a general idea would be helpful.

    I am also looking for data on overall accessory load (kW preferably), and a breakdown would be even better.

    Thanks for the help!
     
    #1 djm74, Nov 9, 2006
  2. ken1784

    ken1784 SuperMID designer

    Joined:
    Dec 18, 2003
    2,940
    1,365
    67
    Location:
    Yokohama, JAPAN
    Vehicle:
    2010 Prius
    Model:
    N/A
     
    #2 ken1784, Nov 9, 2006
  3. hdrygas

    hdrygas New Member

    Joined:
    May 22, 2004
    3,650
    6
    0
    Location:
    Olympia Wa
    Vehicle:
    2004 Prius
    I run 2-3 amps with the light air and radio on.
     
    #3 hdrygas, Nov 11, 2006
  4. donee

    donee New Member

    Joined:
    Aug 15, 2005
    2,956
    197
    0
    Location:
    Chicagoland
    Vehicle:
    2010 Prius
    Model:
    III
    Hi Djm74,

    I did some simple analysis on Atila's data. Its detailed in http://www.priusonline.com/viewtopic.php?t...asc&start=0 . The short answer was Attila got 81.5 percent regeneration efficiency ( Energy of regenerated electricity / Energy of Car Motion), and 66.6 percent electric acceleration efficiency (Energy of resulting motion / Energy of electricity applied to motor).

    The Efficiency of reuse was then .815 times .666 times battery efficiency (times 100 percent) or 54.3 percent times battery efficiency .

    Guidance from this info is that the electric acceleration is not super efficient. Cruise would be more efficient as the motor and inverter losses are approximately a fixed resistance, and lower currents would result in less energy dissipated as heat.
     
    #4 donee, Nov 12, 2006
  5. djm74

    djm74 New Member

    Joined:
    Nov 9, 2006
    2
    0
    0
    Thanks for the info. The efficiency of reuse must assume there is enough storage space available in the battery to recapture that much energy. The model I am trying to come up with needs a single reuse value, so do you think I should further discount the efficiency to account for this occassional lack of storage space issue? Or is the battery almost never topped off enough to preclude sending the regen energy back to it?

    Thanks!! :D


    <div class='quotetop'>QUOTE(donee @ Nov 12 2006, 07:50 AM) [snapback]347768[/snapback]</div>
     
    #5 djm74, Nov 13, 2006
  6. DanMan32

    DanMan32 Senior Member

    Joined:
    Aug 27, 2004
    3,799
    26
    0
    Location:
    Tampa Bay, FL
    <div class='quotetop'>QUOTE(djm74 @ Nov 13 2006, 01:14 AM) [snapback]348067[/snapback]</div>
    Well, you can't put 10 gallons in a 5 gallon bucket, so there will be a point where the battery will not be given a charge from regen. Slowing down without regen provides 0% efficiency, so it does sound like you need to factor that in.

    Or perhaps I am not understanding your last post.
     
    #6 DanMan32, Nov 22, 2006
  7. 2009Prius

    2009Prius A Wimpy DIYer

    Joined:
    Mar 25, 2009
    2,705
    510
    63
    Location:
    USA
    Vehicle:
    2009 Prius
     
    #7 2009Prius, Oct 2, 2011
  8. SageBrush

    SageBrush Senior Member

    Joined:
    Jun 4, 2008
    11,627
    2,530
    8
    Location:
    Southwest Colorado
    Vehicle:
    2012 Prius v wagon
    Model:
    Two
    I wondered what the average energy/time dissipation of kinetic energy was --
    mv^2/2
    1400 * 20 * 20 /2
    = 14000*20 = 280000 joules = 12.4 kw (over 22.5 seconds)

    This rate is less than simply taking the foot off the go pedal according to Attila's graph that Ken linked to, so the general advice to apply 'gentle but firm pressure' does not make sense to me.

    With a scangauge I think one could shoot for 5 - 10 amps going into the battery during the braking event and get good results, but that is a guess.
     
    #8 SageBrush, Oct 2, 2011
(You must log in or sign up to post here.)