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Dead starting battery

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Benevento, Nov 22, 2005.

  1. Benevento

    Benevento New Member

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    I did a search but couldn't find a topic quite like the problem I experienced.

    I drove from Michigan to New York (ie, the car wasn't sitting for a week), and in the morning I was going to show my friends what a nifty new (2005) Prius I had. But it was completely dead. I even had trouble getting it open, and there were no lights on the dash, etc. So my questions are:

    1. Is there no indicator for the starting battery (as opposed to the drive battery) like most regular cars have?

    2. The car was off, the doors closed and locked. The 12-volt accessory outlet doesn't work if the car is off, but there was nothing plugged in anyway. We were driving in daylight, so I'm sure the dome light was off. How could the starting battery die?

    3. I called the service number and a guy came right out (though he had seen only one other Prius in his life and needed my Owners Manual to know how to charge the battery). After charging the battery he advised me to keep the car running to charge the battery (makes sense for an "ordinary" car). But the drive battery (the only battery I could see on the panel) was low but OK, and the gas engine kept shutting off, so it couldn't be charging anything. The only way I could charge the drive battery (and presumably the starting battery) was to take it for a drive and go down some big hills. Why would the gas engine go off when the battery (either one) is low?

    4. This is a silly question since I don't know what I did to cause the starting battery to die, but what can I do to avoid it in the future? It has not happened since then (around last May), but I certainly don't want it to happen again especially with winter setting in.
     
  2. efusco

    efusco Moderator Emeritus
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    Answers NOT in the order you asked the questions:
    1)The 12v (starter) battery is charged NOT by the ICE (engine) but by the HV (drive) battery directly. The ICE need not be running and it charges up pretty quickly.

    2)I suspect the reason it died was b/c the hatch may not have been completely closed/latched. That's the most common cause. If you know that with 100% certainty to not be the case then you need to have your battery tested as it may be bad. Barring that you should have the vehicle checked for other parasitic drains by your dealer if the problem (dead battery every morning) persists. But if this was a one-time deal you either left the car in Accessory mode (do you have SKS? it's easy to do on accident), or the rear hatch was open and that causes the dome light to stay on which can drain the battery.

    3)You should not "charge" through the under the hood contacts. Those are jump points. Once jumped the HV battery will charge the 12v.

    --evan
     
  3. Marlin

    Marlin New Member

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    Actually, the dome light doesn't stay on if you leave the hatch open. At least now on my '05. It turns off after 10 minutes or so.

    When my family went to see some fireworks back around July 4th, we left the hatch open and let my daughter sit in the back while we waited. About 10 minutes later, the dome light turned off on its own. A little after that, I opened one of the side doors to get something, and the light came back on. 10 minutes or so later, it turned off again.
     
  4. naterprius

    naterprius Senior Member

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    Do you have a JBL Amp? If so, it may be the cause. There is a TSB on this. See your dealer.

    Nate
     
  5. IsrAmeriPrius

    IsrAmeriPrius Progressive Member

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    The dome lights do turn off; however, the hatch compartment light stays lit as long as the hatch door is not properly latched.
     
  6. ross33

    ross33 New Member

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    i had the same problem once. turned out i had unclipped my cargo net and it held the rear hatch open enough to cause the door ajar lite on the dash to stay on and it killed the battery.
     
  7. andyprius

    andyprius Senior Member

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  8. andyprius

    andyprius Senior Member

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  9. Tideland Prius

    Tideland Prius Moderator of the North
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    The cargo area light won't drain the battery. My dad left it on overnight (hatch ajar) and it worked fine the next morning. A few months later, my battery mysteriously died while at school.
     
  10. IsrAmeriPrius

    IsrAmeriPrius Progressive Member

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    I found out that the cargo area light does not automatically turn off when I found it lit in the morning after it was on all night when my wife or daughter failed to close the hatch door properly after taking out the school backpack the previous evening. Yes, the car did start.