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Aux Battery woes

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by cdweller0, Jan 11, 2011.

  1. cdweller0

    cdweller0 New Member

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    I have a 2005 that I drive most every day without problem. I do have one quirk that I haven't heard of before. If I don't drive it for 3-4 days, it just won't start without a jump. My understanding is that is should be able to go much longer than this without use. I replaced the auxiliary battery last year in attempt to fix the problem, but it just happened to me again. I would guess it's a wiring problem?

    My two conversations with the dealer have not gone well at all. I'm told that everything checks out fine. "Yes, because I just drove it here," I seethe (politely). I've joked about having to take my car for a walk often enough that it's just practice now. As I am riding my bike around the neighborhood more, including going to work, you can see how this is going to become a much bigger issue in the near future.

    Of course I'm looking into a second opinion. If need be I am willing to leave it with a shop for a few days so they can see the problem firsthand while I go about my merry way in a rental. I'd like to avoid that route/expense! I checked the stickies and searched the forum, but perhaps not well enough. Has anyone heard of this before? Or have any advice for me?
     
    #1 cdweller0, Jan 11, 2011
  2. snead_c

    snead_c Jam Ma's Car

    Joined:
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    Location:
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    Vehicle:
    2013 Prius
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    Four
    :(
    Some thoughts from a nonexpert:
    It sounds like the aux bat is running down while parked. Something might be draining it...rear overhead light ?
    Check all lights, hatch and doors to be sure they're secure.
    Are the cables securely attached to the battery ?
    Has the battery been abused by frequently run down by radio etc?
    Have the "new" battery checked to see if it has lost its ability to hold a charge. At just over 1 year old it may be defective and probably eligible for a free or very cheap replacement.
     
    #2 snead_c, Jan 11, 2011
  3. KK6PD

    KK6PD _ . _ . / _ _ . _

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    If it indeed is a 2005, and it's the original battery, time to dump it and get a new battery. The old one is just used up!! The battery of choice is the Yellowtop Optima. Here is a site that is in So Cal, you could drive over and pick up the battery, well if your car will start, or they will ship it to you. I got a battery about 4 months ago from them, they also have the kit to adapt it to the Prius! Here is the URL...

    Prius parts
     
    #3 KK6PD, Jan 11, 2011
  4. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Two
    1. If you have access to a digital multimeter, you can measure quiescent current draw from the 12V battery when the Prius is IG-OFF, by disconnecting the negative terminal cable where it connects to the body, and putting the DMM in series. Should be around 20 mA. If much more, then your car has a problem.

    2. If #1 does not show any problems, you may need to hook up a battery charger weekly, or else use a battery minder, in order to keep the 12V battery charged up. It sounds like you may not be driving the car sufficiently.
     
    #4 Patrick Wong, Jan 11, 2011
  5. FlyboyTR

    FlyboyTR Member

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    Three
    Good suggestion made about checking the current draw with a multimeter. However, If you don't have one... you could just disconnect the battery (ground) and then let it sit for the obligatory 3-4 days, reconnect and see if it starts. If is doesn't start...battery issue. If it does start, you've got an excessive parasitic load on the battery.

    I agree with the earlier post about checking lights that are in the ON position, etc.
     
    #5 FlyboyTR, Jan 11, 2011
  6. richard schumacher

    richard schumacher shortbus driver

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    Any aftermarket or 3rd party electronics installed?

    Do you use the radio or other accessories with the car in ACC (not ON/Ready)?
     
    #6 richard schumacher, Jan 16, 2011
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