AC quits when parked with motor running

Discussion in 'Gen 2 Prius Technical Discussion' started by Roger3125, Sep 5, 2006.

  1. Roger3125

    Roger3125 New Member

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    I asked this before and still am not sure if I understood the replies I received.

    This was my experience. I parked the Prius with motor running and left the AC on. It was 98 that day.

    Being a little concerned about using up the battery I kept an eye on the bars. After about 20-25 minutes the bars were gone and although the fan was still pushing air it was not cold air. It was like the AC quit.

    I let it sit for a bit and restarted it and again no air. I pushed a few buttons on the Climate display and the air went on again.

    So now I wonder is there something wrong with my Prius system or was the little brain telling the Prius components to concentrate on one thing and ignore what is perhaps less import...such an the interior comfort. Or maybe I accidently hit something that turned off the air.

    Can someone tell me if this is they way it should be and if so what is the reasoning for desgning the Prius tthis way.

    Also can someone suggest a better way to have AC while parked.

    Thanks all
     
  2. glenhead

    glenhead New Member

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    Did you have it fully on, that is, could you have flipped it into drive and driven off? If yes, then I can't help - mine keeps cycling the gasoline engine as needed to keep the batteries happy. I've sat (twice now) in 100+ degree weather for more than a half hour waiting for my ex-wife to get to bring our daughter to our meeting place at the end of her weekend, and it's kept me nice and cool with no problems.
     
  3. efusco

    efusco Moderator Emeritus
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    Probably the reason you didn't understand the answers is b/c we kept asking for clarification of some things that you didn't explain well.

    In this case you make reference to "the bars went away"--what does that mean? How many bars were you seeing on the Energy display?

    Then you mention "restarting it" after a bit...did you shut the car off and the start back up in ready mode?

    You mention "pushed a few buttons on the Climate display"--what buttons? What adjustment did you make?

    Here's my take...the system is working normally. In Auto mode, the AC system will decrease output when you're stopped in order to conserve the battery as much as possible. It will not shut off completely but may let the temperture wander upward a bit higher than it would during normal driving.

    If you were uncomfortably warm and wanted it cooler then simply adjust the temperture setting downward a few clicks...ie if you were on 78 when you stopped and started feeling too warm and feel the AC isn't cooling enough drop the temp setting to 76. The AC will kick out cooler air. It'll probably force the ICE to start up to recharge the battery more often and for longer time periods, and it will decrease your fuel economy, but your comfort is important so do it.

    Alternatively, if you want full control, just set the temp where you want it and the fan where you want it thereby taking in out of Auto mode and it will run at that temp and fan speed the whole time and start and stop the ICE to charge the battery as needed.
     
  4. ken1784

    ken1784 SuperMID designer

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    <div class='quotetop'>QUOTE(Roger3125 @ Sep 6 2006, 11:16 AM) [snapback]314924[/snapback]</div>
    Which motor are you talking about?
    Are you in READY mode or IG-ON mode?
    Where was the shift position? (P, N, D, B, which one?)

    [email protected]
     
  5. hdrygas

    hdrygas New Member

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    <div class='quotetop'>QUOTE(efusco @ Sep 5 2006, 08:38 PM) [snapback]314978[/snapback]</div>
    Set the system and it will do what is necessary. If it is too hot, and it may be sitting in the parking lot stopped, decrese the temp request the car will take care of the rest. It will turn the ICE on or off as needed and run the AC as needed. All of this cooling will cost you but you will be good.
     
  6. bradysplace

    bradysplace Junior Member

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    <div class='quotetop'>QUOTE(Roger3125 @ Sep 5 2006, 09:16 PM) [snapback]314924[/snapback]</div>

    Hi Roger, your explanation appears to be a bit vague and that may explain why the replies haven't been as clear as you might like. Let me tell you how my 06 prius works. When waiting - put the car in park and leave everything alone. Period. As the batt. discharges the ice will start up to recharge as necessary and then stop. That will continue to repeat itself over and over as long as your just sitting there. The air cond. will continue to work just fine in either the recir. mode or outside air mode. If your car is not reacting in this manor - take it to a dealer. Toyota made this thing for the weakest link - so let their expertise work for you.
     
  7. eak354

    eak354 Member

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    <div class='quotetop'>QUOTE(Roger3125 @ Sep 5 2006, 09:16 PM) [snapback]314924[/snapback]</div>

    sounds like you weren't in READY mode. the engine will automatically kick in when SOC goes down to 2 bars. likewise, when not in READY mode the A/C won't work, the fan will, but it won't cool.
     
  8. kDB

    kDB New Member

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    did you have it on auto with a temp above 75? maybe the a/c was on auto and started blowing at max, then when it got near the temp set on the mfd it started turning itself down.
     
  9. tduescher

    tduescher New Member

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    I also recently found that the A/C will cause the ICE to automatically start, recharge the HV battery and continue to cycle through charging the battery. Ran it this way for about 1/2 hour. Seeing the purple bars does make me nervous but it cycled this way without problem.

    I also noticed that if you press the accelerator while it is in ready mode and Park but the ICE is not running that the ICE will start and accelerate but does not appear to charge the battery in this mode. Can anyone explain why the engine starts when pressing the accelerator in Park but does not Charge the HV battery.

    What makes this different from the computer telling the ICE to start and charge the battery?
     
  10. fphinney

    fphinney Member

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    <div class='quotetop'>QUOTE(eak354 @ Sep 6 2006, 04:48 AM) [snapback]315068[/snapback]</div>
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    WAIT A MOMENT!...
    Are you saying that, "...the A/C won't work, the fan will, but it won't cool." I thought the A/C was operated by an electric motor - - which means that it is NOT dependent on the ICE!

    Think about this way. Get the battery well charged (like after descending a long hill). Shut down the car. Go back a few hours later (or the next day), get the car in the "Ready" mode, & leave it in "Park". Operate the A/C. I contend that you will get cold air in a moment or two, & the ICE will have not started!

    Correct me, if I'm wrong -
     
  11. efusco

    efusco Moderator Emeritus
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    <div class='quotetop'>QUOTE(fphinney @ Sep 11 2006, 11:53 PM) [snapback]318154[/snapback]</div>
    Your quoting and question are not clear to me here and I'm not sure who you're asking the question of.

    But here are the facts:
    1)The AC will only run in READY mode...
    2)The AC is operated via an electric motor and is not directly connected to or dependent upon the ICE
    3)In IG On mode the fan will blow but the compressor will not run
    4)The fact that AC will not run in any mode besides ready is because this is regulated by the computers in the car to prevent rapid depletion of the 12v battery.
    5)The 12v battery would drain rapidly in IG ON mode b/c the HV battery is disconnected from the rest of the electrical system in all conditions except ready...thus the DC-DC converter could not send charge to the 12v battery from the HV battery.

    Finally, If I start my car into ready mode the AC will start working (at a low output) before the ICE starts...but the ICE will still start and run for at least a few minutes until the ICE/coolant temps are warm enough for it to shut off. The AC will then, of course, continue to run, often at a slightly lower output than it did during the ICE-on time until the battery gets low and the ICE kicks in again to recharge it.

    Does that clarify things any?
     
  12. curtissac

    curtissac New Member

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    <div class='quotetop'>QUOTE(Roger3125 @ Sep 5 2006, 09:16 PM) [snapback]314924[/snapback]</div>
    Were you in PARK? The A/C is electric and draws power from the batteries. If you you selected NEUTRAL instead of PARK, the ICE will not charge the batteries and I would assume the A/C will shut down wheh the batteries "turn purple". The fan will probably keep running off the 12V system with the ICE running.
     
  13. KMO

    KMO Member

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    Evan, the A/C compressor actually runs off the high voltage system - the only thing to do so other than the main motors. That's a more fundamental reason for it not working in IG-ON than just not wanting to run down the 12V battery.

    Nevertheless, the point about power is true. The power requirements of the A/C compressor are huge - something like 3kW - that'd be 250 amps from the 12V system, which is why you don't see normal cars using electric A/C! The 12V battery would last 5-10 minutes at full blast.

    In contrast, 3kW is fairly minor compared to the 25kW the HV battery can supply, or the 50kW overall rating of the main drive motor. Still doesn't last long before needing to start the engine to recharge though - the HV battery actually only has about 4 times the capacity of the 12V battery, interestingly, and it only uses under half that. You'd be lucky to get 15 minutes of full-blast A/C without starting the engine.
     
  14. curtissac

    curtissac New Member

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    <div class='quotetop'>QUOTE(KMO @ Sep 12 2006, 04:27 AM) [snapback]318215[/snapback]</div>
     
  15. efusco

    efusco Moderator Emeritus
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    <div class='quotetop'>QUOTE(KMO @ Sep 12 2006, 04:27 AM) [snapback]318215[/snapback]</div>
    Ok, thanks for checking behind me...I had thought that the HID headlights were the only thing other than motor that ran off the HV battery....
     
  16. KMO

    KMO Member

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    The power steering is purely 12V, through the 50A EPS fuse. It's activated at IG-ON.

    And the HID headlights - I'm pretty certain they'd be off the 12V too, just like any other car. I can't say for certain, not having US wiring diagrams, but if they weren't 12V you wouldn't be able light them in ACC or IG-ON.
     
  17. efusco

    efusco Moderator Emeritus
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    I'm pretty certain that the DC-DC converter for the HIDs is within the headlight assembly....but that's going on memory from a couple years back.
     
  18. mrg

    mrg Member

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    I have had the A/C problem myself on my 2004 Prius. I do not recall when it happened. My wife was driving and stopped at a drug store. She parked and left the motor running with A/C on and cooling fine, she just pushed the park button and said I'll be right back. I was setting in the passenger seat with our granddaughter in the back seat. The A/C was fine for a few minutes but stopped cooling. I kept thinking she would just be another minute or so. We got pretty warm. I pushed some buttons (maximum, etc.). It was not cooling anymore. Nothing I changed worked. I did not turn the car off. I assumed it was a hybrid problem.

    My wife finally came out and after resuming driving a few blocks it began to cool again. I have advoided parking with the motor running to keep cool. I turn the car off and go inside.
     
  19. richard schumacher

    richard schumacher shortbus driver

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    When the car is not moving there's little air moving through the engine compartment (where the A/C heat exchanger is) so it gets very hot in there. This makes it difficult for the A/C to remove heat from the cabin.

    On the other hand I've parked in Dallas for a half hour and the A/C kept working just fine, so perhaps yours does have a problem, or perhaps the A/C was somehow turned off in a way that was not obvious at the time.
     
  20. ken1784

    ken1784 SuperMID designer

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    <div class='quotetop'>QUOTE(mrg @ Sep 15 2006, 12:08 PM) [snapback]319891[/snapback]</div>
    Where was the shift position, P or N?
    What was the battery level then?

    [email protected]


    <div class='quotetop'>QUOTE(richard schumacher @ Sep 15 2006, 11:15 PM) [snapback]320047[/snapback]</div>
    When the car is not moving and AC compressors is on, the cooling fan runs in high speed condition to do enough cooling.

    [email protected]
     
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