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How to prevent accessory mode from turning off after 30minutes?

Discussion in 'Gen 3 Prius Main Forum' started by herqulees, Apr 1, 2016.

  1. herqulees

    herqulees Junior Member

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    So lucky us we actually still have a drive in theater nearby meaning were parked in Accessory mode for 4+ hours to use the radio without having the whole dash lit up. Is there any way to disable or at least temporarily stop the Prius from turning off Accessory mode after 30minutes? It's annoying as you can't even just turn it back on you have to open and close a door before you can go back into Accessory mode.
     
    #1 herqulees, Apr 1, 2016
  2. drysider

    drysider Active Member

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    You don't need to go to Accessory mode. Just put in park. It will stay in Ready mode and run the engine as needed to both charge the battery and keep the coolant hot. The car has been run in Ready for days at a time.
     
    #2 drysider, Apr 1, 2016
  3. xliderider

    xliderider Senior Member

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    Acc mode = risk a dead 12v auxiliary battery. Ready mode is better, turn down the dash illumination, throw a towel over the dashboard if you want. ;)
     
    #3 xliderider, Apr 1, 2016
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  4. RRxing

    RRxing Senior Member

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    Accessory mode turns off after 30 minutes? Are you sure about that? o_O
     
    #4 RRxing, Apr 2, 2016
  5. herqulees

    herqulees Junior Member

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    I can promise you all that there is next to no risk of running the 12volt battery down in a Prius. A simple radio hardly draws anything and the 12volt battery does nothing but click a few relays to start the car.
    We ended up leaving the Prius in Run mode, not Ready, and covered the dash with a blanket for the approx six hours. Run mode shuts off after an hour, so still annoying but not as bad as Accessory shutting off after 30minutes.
    So does anyone know of a way to circumvent this?
     
    #5 herqulees, Apr 2, 2016
  6. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    So does anyone know of a way to circumvent this?


    Yes, stay in Ready. The prius 12 volt battery is tiny and will run down rapidly. Do not attempt to.power anything with 12 volts alone.
     
    #6 JimboPalmer, Apr 2, 2016
  7. RRxing

    RRxing Senior Member

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    I'm still confused. Pressing the Power button without your foot on the brake puts you in Accessory mode so you can listen to the radio (and run down the 12V battery.) Pressing the Power button a second time without your foot on the brake puts you in On mode and all electrical components can be operated (and run your 12V down even faster.)
    There is no "Run mode" - only Off/Accessory/On/Ready. Unless they changed it for the 2014 model year.
     
    #7 RRxing, Apr 2, 2016
  8. herqulees

    herqulees Junior Member

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    You and I both know that's not an answer.Run/On. I called it Run since that's what it's called on the ignition of other vehicles, didn't realise people just called it On for the Prius. So to correct myself I had my Prius switched to On for six hours, it timed out every hour and I had to press the power button twice to turn it back on, every hour. We just covered the dash in a blanket to block all the lights and turned the screen off on the radio. Either way, I had my Prius in On mode for six hours, roughly half an hour of that was also with the interior lights on. You can not easily run down a Prius 12volt battery just listening to a radio, and leaving the car in Ready mode is not an answer. I am not going to waste gas just so my radio doesn't turn off every 30/60minutes.
     
    #8 herqulees, Apr 2, 2016
    Last edited by a moderator: Apr 2, 2016
  9. RRxing

    RRxing Senior Member

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    Well, if you say that On mode times out every hour, then it times out every hour. I don't remember seeing that in the owner's manual or anywhere else. Personally, I won't test it myself. I prefer Ready mode, the amount of gas wasted is insignificant compared to a dead 12V battery.
     
    #9 RRxing, Apr 2, 2016
  10. bisco

    bisco cookie crumbler

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    if you put it in ready mode, it's not using much power, so your engine shouldn't come on.
     
    #10 bisco, Apr 2, 2016
  11. herqulees

    herqulees Junior Member

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    Back when I had a 2007 Prius, which just recently had a hybrid battery failure and we traded it in for this 2014, we could use Accessory mode for an hour before it turned off. I'm not sure if On mode turned off after an hour as I don't recall testing it. It wasn't as bad because all we had to do is press the power button real quick and we only miss about three seconds of dialog from the movie.
    However with this generation you have to open/close the door to re-enable the power button after Accessory mode times out with a message on the HUD saying something along the lines of "Accessory mode disabled to conserve auxiliary battery" (I would assume I could press the brake and Ready mode would still work, I didn't try that though).
    Basically I started this thread hoping someone knew a button combination or something to disable this timeout like there was on my old Prius to disable the backup beep or reset the oil change light. However it's looking like nothing exists. I do want to add why I have 0% worry on a dead 12volt battery is both because the load from just the radio is so low, plus we only need this at the drive in which has multiple battery jump pack people that walk around after the movie is over. So if it really did die on us we just have to flag a guy over.

    I just downloaded the manual from Toyota and it took a bit to find it but I finally did;
    "Auto power off function
    If the vehicle is left in ACCESSORY mode for more than 20 minutes or ON mode (the hybrid system is not operating) for more than an hour with the shift position in P, the “POWER” switch will automatically turn off."

    Well I suppose things could have changed from our last generation (2007) Prius. With no heat/AC on the hybrid battery would drop to two bars after 5-10minutes making the engine start and run for 5minutes. (We didn't know at the time this was a sign of a bad battery) This was both wasting gas and I'm not sure if it was just our Prius or normal for the last gen Prius but it jumped forward whenever the engine starts and stops.
     
    #11 herqulees, Apr 2, 2016
  12. drysider

    drysider Active Member

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    I hope somebody else is as confused as I am. Put the car in Ready mode, not Accessory or On or anything else. With the car Off, put your foot on the brake and push the Power button ONCE. That's it. The Ready light on the dashboard will come on and the car will take care of the rest.
     
    #12 drysider, Apr 2, 2016
  13. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    I know it is the right answer, and i can see you want some other answer.

    No other answer will not discharge the 12 battery ($200)
     
    #13 JimboPalmer, Apr 3, 2016
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  14. David Beale

    David Beale Senior Member

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    You WILL dangerously (for its life) discharge the 12V battery in any mode other than "ready" if left in that mode for longer times. As in longer than about 10 minutes. It has been done by other owners and reported on this forum countless times! Yup, there can be current draw as little as a few amps. Yup, the 12V battery has about 38 A-Hr capacity -when new-. HOWEVER, things are not that simple. The headlamps can stay on, for example, unless you open and close the drivers door in some situations. The fan running will increase the draw. Lots of things you may forget about.

    Just use "ready". What's so difficult about this? Listen to the owners with experience! The engineers knew this could be a problem. That's why the car is shutting off on its' own (though that's the first time I've ever heard of that).
     
    #14 David Beale, Apr 3, 2016
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  15. cproaudio

    cproaudio Speedlock Overrider

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    Not sure if the radio is turned on by canbus. If it's turned on by 12v through acc wire like an older car, you can jump a constant 12v to the radio's acc fuse at the fuse box. Since you're bypassing the cars acc mode, the radio will never turn off. No other part of acc electrical system will get power except for the radio which the battery could last even longer. Once you're done at the movies, remove the piggy back fuse and insert the regular fuse and be done. Your battery is still new and can take this kind of abuse. Give it another year and you'll know why we have concerns about running in acc mode for such a long time.
     
    #15 cproaudio, Apr 3, 2016
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  16. CR94

    CR94 Senior Member

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    You're correct that "a simple radio" (like the basic version in Prii) draws so little current at reasonable volume level that it would take many hours to discharge the battery much. However, even with no accessories turned on, a Prius in "ACC" mode draws several times more current than the radio alone does. For that reason, people here who are warning you of discharging the battery with prolonged use of "ACC" are correct, and Toyota is trying to save you from killing the battery with that automatic shutoff.

    Yes, it's annoying that you and I can't listen to the radio long in "ACC" without abusing the battery, as I could in previous cars. That's not because the battery takes so much power, or that the battery is far smaller than others, as some people will try to tell you. It's because of the vampire current drain is so high in "ACC."
     
    #16 CR94, Apr 3, 2016
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