Power Loss

Discussion in 'Gen III 2010+ Prius Technical Discussion' started by jwads, Jan 23, 2012.

  1. jwads

    jwads New Member

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    Was sitting in my car on my lunch break playing the radio and had my seat heater on, and all of a sudden my radio kinda went staticy and died and my car completely died. Had to power it back down then back up to get it running, battery didn't show very low, but when I went into start mode (non accessory) it immediatly started the ICE and charged.

    Wondering if this happened to anyone else?
     
  2. cwerdna

    cwerdna Senior Member

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    What mode were you in? Were you in IG-ON or READY? If latter, where you in any "gear" other than Neutral?
     
  3. jwads

    jwads New Member

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    Im not sure. I was in what I call AUX mode, like where your radio and stuff works but the car won't drive b/c I hadn't pressed on the brake. I was still in park, wasn't driving in any gear
     
  4. cwerdna

    cwerdna Senior Member

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    DO NOT run your Prius for too long in either ACC or especially ON (formerly known as IG-ON) otherwise you will drain the very small 12 volt very rapidly, which isn't good for it.

    I have a 2nd gen so I have no seat heaters (weren't available). ACC should be where the stereo works but you don't see any dash indicators. ON should be the above + turn all the warning lights initially and leave most of the dash indicators on. See pages 164-167 of your manual.

    If you want to sit there w/the stereo and esp. the seat heaters for a long period, you should be in READY mode (READY indicator on the left). Being in READY mode allows inverter to supply power to the 12 volt bus, charges the 12 volt and allows the ICE to fire up to maintain charge on the HV battery.
     
  5. ETC(SS)

    ETC(SS) The other One Percenter.....

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    Concur!
    You may want to start learning how to replace your 12V battery.
     
  6. qbee42

    qbee42 My other car is a boat

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    Don't do that. That's the simple answer.

    Tom
     
  7. ken1784

    ken1784 SuperMID designer

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    Owners manual says...
    Code:
    [B]Auto power OFF function[/B]
    If the vehicle is left in ACCESSORY or ON mode (hybrid system is not operating)
    for more than an hour with the shift position in “Pâ€, the “POWERâ€
    switch will automatically turn OFF.
    Ken@Japan
     
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  8. kithmo

    kithmo Couch Potato

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    UK model turns ACC off after 1 hour to prevent flattening the 12v.
    just beat me to it Ken ;0)
     
  9. jwads

    jwads New Member

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    Good to know. I know I wasn't in that mode for an hour though, but still good to know. I was under the impression the Prius had a huge battery, so doing that wasn't a problem. Good to know!
     
  10. seilerts

    seilerts Battery Curmudgeon

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    Charge that 12V asap. 2 amps for 10 hours.
     
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  11. jwads

    jwads New Member

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    Ya, ive been running it a lot since, and haven't kept it in AUX mode ever. How exactly does it flatten the battery? Why isn't it a normal charge recharge cycle?
     
  12. cwerdna

    cwerdna Senior Member

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    The "huge battery" (the HV battery, in the metal box that runs the width of the vehicle) is not in use when you leave it in ACC or ON (aka IGN-ON) mode. It's running off the tiny 12 volt in the rear corner which is not being charged via the inverter while in those two modes.

    This is why you should be in READY mode if you want to run the radio, seat heaters or any accessories for any length of time.
     
  13. richard schumacher

    richard schumacher shortbus driver

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    To sum up: leave it Ready, shifted to Park, and the parking brake set. Then you can listen to the radio until it runs out of gas, which will take something between two days and two weeks.
     
  14. jwads

    jwads New Member

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    Ya, Ill have to do that from now on, I always thought it used the huge car battery. Is there any way to get a charge on the little 12 volt in the back from any of the main indicators up front?
     
  15. seilerts

    seilerts Battery Curmudgeon

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  16. qbee42

    qbee42 My other car is a boat

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    Your Prius must be Ready and not in N to allow the engine to charge the battery. If you sit in Park the engine will come on and charge when necessary, then turn back off.

    In Acc mode the small 12V battery is on its own; it doesn't get recharged by the big battery no matter how dire the level of charge.

    In Ig-on the 12V bus is being supplied by the big battery, but the engine cannot come on to recharge the big battery. All of the circuits are powered up in Ig-on, so it doesn't take a long time to run down the big battery.

    Tom
     
  17. lorraine

    lorraine New Member

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    My car losses power sometimes when I am driving it. I have to pull over and restart and then it is fine. Has anyone else had this problem?
     
  18. AtoyotA

    AtoyotA Junior Member

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    Hmmm, good clear explanation of the difference. I was never quite sure which did what. Thanks!
     
  19. seilerts

    seilerts Battery Curmudgeon

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    Can you give us more details? Do warning lights come on? Is the engine revving high, or is it completely off? Do you hear the hv battery fan running in the back?

    Power loss while driving is definitely not normal.
     
  20. lorraine

    lorraine New Member

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    No warning lights come on. Not revving high, everything seems normal. I told my dealer about this and he said he did not have any other complaints.
    Car is fine otherwise. Can it be bad gas?