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

no power going uphill w/ AC on?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by hoodenc, Sep 11, 2009.

  1. hoodenc

    hoodenc Junior Member

    Joined:
    Mar 29, 2008
    17
    0
    0
    Location:
    Los Angeles, CA
    Vehicle:
    2004 Prius
    Hi everyone,

    On a hot day a few weeks ago, I had the AC on and was going up a steep hill when I lost power after just a few minutes. The vent in the back seat was blowing air loudly, the first time I had ever heard that happen. No warning lights on the dashboard, just very little power. The engine strained every time I hit the gas. I pulled over, restarted, turned off the AC, and the car seemed to run fine after that.

    Just wondering if anyone else has encountered similar problems. Is this abnormal, and something I should get checked out? Or is running the AC while driving up a steep hill on a hot day just a bad idea?

    Thanks!
     
    #1 hoodenc, Sep 11, 2009
  2. ragman

    ragman New Member

    Joined:
    Aug 9, 2009
    25
    5
    0
    Location:
    Chichester, NH
    Vehicle:
    2007 Prius
    Model:
    N/A
    Sounds like your HV battery got hot. It kicked the battery cooling fan on (on hi or just on and off?) and started to cut out power to the electric motor to keep the batt temp down.

    Is your A/C compressor electric?
     
    #2 ragman, Sep 11, 2009
  3. donee

    donee New Member

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

    The vent noise indicated the battery was warm, and the car decided not to give you any battery power until the battery cooled. Which probably means you went up the hill you started at a low battery state of charge, or went up so fast that the battery was needed to maintain the speed. I find the car warms more when there is a tail wind. As the airspeed is less, and thus less cooling.

    To avoid this in the future, avoid yellow arrows going up a hill, if its long. Get a steady state speed going with just the engine providing power.
     
    #3 donee, Sep 11, 2009
    1 person likes this.
  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
    Did it ever do this before, on the same hill in the same heat? If not, and if it happens again you might ask a dealer for diagnosis. Otherwise it's happenstance: the battery was drained when you hit the hill on that trip, or the car was really hot in the Sun and you had not been driving long enough for the AC to cool down the cabin (and thus the battery system).
     
    #4 richard schumacher, Sep 11, 2009
    1 person likes this.
  5. patsparks

    patsparks An Aussie perspective

    Joined:
    Jul 12, 2007
    10,664
    567
    0
    Location:
    Adelaide South Australia
    Vehicle:
    2004 Prius
    Model:
    N/A
    Use open vents in hot weather to keep air going through the battery with the AC fan, not the recirculating setting. Dont tow trailers, especially in hot weather and roof top boxes arent much better.
     
    #5 patsparks, Sep 11, 2009
  6. hoodenc

    hoodenc Junior Member

    Joined:
    Mar 29, 2008
    17
    0
    0
    Location:
    Los Angeles, CA
    Vehicle:
    2004 Prius
    Thanks, everyone! Yeah, I'm guessing the battery wasn't in the green when I started, and it drained quickly with the steep uphill and the AC on. I guess the best way to avoid this in the future, if I have to go up a steep hill, is just to roll down the windows and not use the AC...?

    Thanks again.
     
    #6 hoodenc, Sep 14, 2009
  7. john5396

    john5396 Junior Member

    Joined:
    Jul 2, 2009
    14
    4
    0
    Location:
    Burlington, NC
    Vehicle:
    2009 Prius
    Model:
    N/A
    Hood,

    A note, the battery was not necessarily drained, but getting hot. The battery will heat both on charge or discharge. So donee's recomendation above is what you need to think about. Can you manage your gas pedal so that there are no arrows in/or out of the battery.

    Since the traction battery is cooled by cabin air, turning off the AC might make the situation worse since that would raise the air temp into the battery compartment making the battery cooling less efficient.
     
    #7 john5396, Sep 14, 2009
    1 person likes this.
  8. hoodenc

    hoodenc Junior Member

    Joined:
    Mar 29, 2008
    17
    0
    0
    Location:
    Los Angeles, CA
    Vehicle:
    2004 Prius
    Hm. But going uphill, isn't it impossible to have arrows in or out of the battery? That is, one can't pulse&glide up a hill, right?
     
    #8 hoodenc, Sep 14, 2009
  9. richard schumacher

    richard schumacher shortbus driver

    Joined:
    Mar 27, 2004
    7,663
    1,038
    0
    Location:
    United States
    Vehicle:
    2004 Prius
    Model:
    N/A
    You can glide up a hill until the car rolls to a stop.
     
    #9 richard schumacher, Sep 16, 2009
(You must log in or sign up to post here.)