2007 Prius 12v Battery failures after 2 replacements

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by mainestreamrob, Jan 16, 2023.

  1. mainestreamrob

    mainestreamrob Junior Member

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    I’ve ordered 2 DEKA 12v batteries off rock auto. The first one was installed 2/21 and the second 8/21. The second is the one in my Prius now and was a warranty replacement for the first one I purchased because it began to die every time I turned on the car off.

    So this second one has been in my Prius for a little over a year and has worked pretty well. Although since winter has begun and the weather is colder out in Maine it’s started to shit the bed again.

    I’m just so confused if it’s the battery or not because once I turn the car off it usually dies immediately and my way of getting it to function again has been banging on the floor of the trunk with my fist and it starts working again. Does this sound like something that would work with a failing battery or more like some bad connection somewhere?

    Any advice is greatly appreciated
     
    #1 mainestreamrob, Jan 16, 2023
  2. SFO

    SFO Senior Member

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    Check the connections, including where the negative strap bolts to the body, as it may be rusted or corroded.

    How many hours per week are you currently driving?
     
    #2 SFO, Jan 16, 2023
  3. mainestreamrob

    mainestreamrob Junior Member

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    From inspection it appears to be okay but maybe I’m missing something? Is there more connections underneath the battery itself? I drive the car a good 8-12 hours a week I’d say. Maybe a little less

    does the tape on the wires look normal?
     

    Attached Files:

    #3 mainestreamrob, Jan 16, 2023
  4. mainestreamrob

    mainestreamrob Junior Member

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    [​IMG]
     
    #4 mainestreamrob, Jan 16, 2023
  5. Tombukt2

    Tombukt2 Senior Member

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    The negative band looks like it has a crack in it whether that's causing you any problems I wouldn't know but connection between your meter and ground and that terminal and moving it around if it can move around while it's on the terminal and the supposedly affixed to the terminal those are definitely not good signs I can't tell from here.
     
    #5 Tombukt2, Jan 16, 2023
  6. mainestreamrob

    mainestreamrob Junior Member

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    It probably is because I went out again and wiggled it to see if anything would happen and the battery went out and turned on once. Just to make sure the band you’re referring to is the one attached to the car in photo #1 correct?
     
    #6 mainestreamrob, Jan 16, 2023
  7. sam spade 2

    sam spade 2 Senior Member

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    Just looking at the point where it attaches to the body is NOT good enough.
    Needs to be loosened, cleaned with a wire brush or sand paper and re-tightened.

    The crack mentioned is where the cable connects to the negative battery terminal.
    It may be damaged........and/or not down far enough on the post.
     
    #7 sam spade 2, Jan 16, 2023
  8. TMR-JWAP

    TMR-JWAP Senior Member

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    The installation job is poorly done and is likely your problem. Neither of the clamps are fully seated on the battery terminals.
    You need to loosen the bolts on the clamps and spread the ends out. Then slide the clamp fully down the terminal until it basically sits on the battery case. Then tighten the clamp. Verify the fastener on the "ground to body" connection is tight.
     
    #8 TMR-JWAP, Jan 16, 2023
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  9. mainestreamrob

    mainestreamrob Junior Member

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    well that would be my fault… I guess I should’ve had it installed by a proper mechanic. I do have an appointment tomorrow so I will have them re install properly and see if the problem is fixed. Thank you for the advice
     
    #9 mainestreamrob, Jan 16, 2023
  10. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    ^ that.

    Take the clamps off, spread them open a little with a screwdriver, and put them back on the battery.

    Then use the back end of the screwdriver to tap them down until they are around the fattest part of the post. (the posts are shallow cones, not straight sided cylinders)

    THEN tighten the clamp bolts.

    This is 100% bad connection on a good battery.
     
    #10 Leadfoot J. McCoalroller, Jan 16, 2023
  11. sam spade 2

    sam spade 2 Senior Member

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    While that may be likely.......you don't KNOW that without being there.
    It is possible that the battery has an intermittent connection INSIDE the battery.
    :whistle:
     
    #11 sam spade 2, Jan 16, 2023
  12. mainestreamrob

    mainestreamrob Junior Member

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    I’ve slid the clamps down and retightened them. If I don’t reply more to this post then the problem was this. Thanks
     
    #12 mainestreamrob, Jan 16, 2023
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  13. dolj

    dolj Senior Member

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    It would be better if you actually came back to confirm that that was the problem. It is preferable than just leaving it for readers to assume that this what fixed the problem.
     
    #13 dolj, Jan 17, 2023
    Last edited: Jan 17, 2023
  14. mainestreamrob

    mainestreamrob Junior Member

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    me not coming back to reply is confirming that was the problem… it hasn’t happened again but it also doesn’t happen everyday
     
    #14 mainestreamrob, Jan 17, 2023
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  15. mainestreamrob

    mainestreamrob Junior Member

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    Problem was solved
     
    #15 mainestreamrob, Jan 21, 2023
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  16. bisco

    bisco cookie crumbler

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    and that's the way we like it! :)
     
    #16 bisco, Jan 21, 2023
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