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2007 Prius won't start after 12v battery drained

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by drlocke, Mar 29, 2015.

  1. drlocke

    drlocke Junior Member

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    Loaned my car to a friend who left something on and drained the 12v battery. Some "good person" tried to jump start the car and was unsuccessful. When I got there I attempted to jump start from the front and direct to the battery in the back, both unsuccessful. After having it hauled back, I charged the battery with my charger, no luck. When I put the keyfob in, press the break, and push the power on button; get green light on the power on button and a check engine light on the panel. This 12v battery is original battery and car has 100K miles. Could really use suggestions, hoping I'm not looking at a $1000 bill at the dealer. Thanks.
     
  2. rjparker

    rjparker Tu Humilde Sirviente

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    If all you need is a battery it should not be $1000 or even half that. First thing you might do is find out what the voltage on the battery is without the charger. If it's over 12.5 then the problem might be bigger. Sometimes it takes 5 minutes with the jumper cables on before it will go because the battery has to absorb some power first. They say as much in the manual. There have been many people fooled by that. Hopefully the good person did not jump it backwards when it did not go immediately..
     
  3. drlocke

    drlocke Junior Member

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    The battery was 12.7 volts immediately after charging, 12.4 volts after 2-3 hrs, and 12.2 volts after 24+ hrs. That would indicate to me that the battery is bad, but would a battery in this condition give the symptoms of no start and nothing else but check engine light?

    Ordered Optima battery. Hope this is the fix, crossed fingers!
     
    #3 drlocke, Mar 29, 2015
    Last edited: Mar 29, 2015
  4. bisco

    bisco cookie crumbler

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    make sure you charge the optima before installing. all the best!(y)
     
  5. rjparker

    rjparker Tu Humilde Sirviente

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    The next step (while you are waiting for your new battery) would be to measure the battery voltage when the car is placed into ready. At that point the car is pulling more amps from the battery, so if the voltage goes down immediately it is definitely bad.
     
  6. fuzzy1

    fuzzy1 Senior Member

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    That battery voltage actually sounds good to me. A Prius should start just fine at those levels.

    Can you measure the voltage while the car is trying to go into 'Ready'? If it stays in the 11+ range, that car still ought to start. If it falls into the 10s or lower, then I'd be more suspicious of the battery.

    A stranger attempting to jumpstart a Prius was a very bad idea. While it is OK if done correctly, a lot can potentially go wrong, and the Prius is far more sensitive to errors than are traditional cars.
     
    #6 fuzzy1, Mar 29, 2015
    Last edited: Mar 29, 2015
  7. Easy Rider 2

    Easy Rider 2 Senior Member

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    No not likely.

    You don't really need a lot of power to kick off the starting sequence.
    And a jump should always work........unless the battery is shorted out, which your's obviously is NOT.

    Alas, your good Samaritan might have crossed the leads and blown a fuse.......or worse.
     
  8. Mendel Leisk

    Mendel Leisk Senior Member

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    Yeah me too. A fresh charged battery, having no subsequent load applied will read high. A new, 100% battery would be close to 13.0 volts in that situation. Being 12.7 right after charging, and dropping that fast to 12.2: not so good.
     
  9. bisco

    bisco cookie crumbler

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    batteries are funny things, beloved by many, but understood by few.
     
  10. Mike500

    Mike500 Senior Member

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    It's lake I've found with almost anything that depends on chemical reactions.

    It's more like "baking a cake," meaning that it is an "art."

    While there are design parameters, little details mean a lot. It is in the process that is oftentimes kept as a trade secret.

    That's why one batch of plastic polymer made by one process might last for a year or two and, another, actually last over 20 years.
     
  11. drlocke

    drlocke Junior Member

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    Update. 12.2 volts before power on, 12.1 when power on is active (green light on button), 11.8 after power on is pushed the second time. We'll know Wed night after the new battery gets here.

    Just read "12V battery replaced with wrong polarity" post which would be the next step if the new battery doesn't do the trick. Guess I'll go ahead and check fuses tonight.

    Update#2. Checked engine fuses, inside fuses and battery fuses. Blown fuses "Dome" and "ETCS". Checked 100A fuse assembly, initially looked good because had voltage at top and bottom. Then noticed that there are 2 main drops on the right side of the assembly that didn't have voltage. Ordered new 100A fuse assembly. Should be in Wed.
     
    #11 drlocke, Mar 30, 2015
    Last edited: Mar 30, 2015
  12. Patrick Wong

    Patrick Wong DIY Enthusiast

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    This is proof that the battery was incorrectly jumped by the "good person" who obviously was color-blind, could not distinguish red from black. This may discourage you from loaning your car in the future...

    The fusible link assembly is not particularly easy to install, it requires unbolting the main relay/fuse box for access to the bottom.

    I hope that the DC/DC converter within the inverter is not blown, which is a distinct possibility given the 100A DC/DC link was blown.
     
  13. bisco

    bisco cookie crumbler

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    all the best.(y)
     
  14. drlocke

    drlocke Junior Member

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    OK, Wed update: Got the new battery and fuse link assembly in. Battery is doing a low current charge before installing. Looking at the new fuse link assembly, I could see how it was designed. Basically metal plates with thin links to output terminals. Removed clear window from the currently installed assembly and quickly saw that the link to the upper right terminal (DC-DC converter?) was blown. Being a risk taker, I jumpered across the blown link. Checked door locks, working. Went to non-ready accessory mode, panel lights working. Break...Power On... engine starts. Master warning light remains on, no other indications or lights. Engaged shifter, short reverse, short forward, ok. Airconditioner works, radio works. Let AC run long enough to pull hybrid battery down past 1/2 and engine started up and indicated charging. Will investigate Master warning light after new fuse link assembly and new battery installed. Will post step-by-step for replacing fuse assembly, assuming I can figure it out. Stay tuned and thanks for the help.
     
  15. RRxing

    RRxing Senior Member

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    Now would be a good time to pull any codes.
     
  16. fuzzy1

    fuzzy1 Senior Member

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    And then clear all codes, then check what reappears. Some codes persist for a while after the actual fault has vanished.
     
  17. drlocke

    drlocke Junior Member

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    Finished, all ok, fuse link assembly and battery replaced. No codes. Will post a DIY on replacing the fuse link assembly under new comment. Thanks to all for the assistance.
     
  18. bisco

    bisco cookie crumbler

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    thanks!
     
  19. koolingit

    koolingit Member

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    I, for one, am really looking forward to the DIY.