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Traction Battery

Discussion in 'Gen 3 Prius Technical Discussion' started by vday, Dec 19, 2014.

  1. vday

    vday Member

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    My prius is almost 5 years old and has 88K Klm (49K Miles)
    My battery has gone down to one bar of late.
    This never happened until recently, never went below two.
    The bars seem to fluctuate up and down much quicker than before.
    My mileage is slightly down but it could be because of other reasons.
    Does it seem that there is something wrong with the battery?
    No warning lights are coming on
    Thanks
     
  2. Blizzard_Persona

    Blizzard_Persona Senior Member

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    Can't hurt to bring it to dealer to test the HV battery. If it's deemed warranty issue you get a new HV battery (3-4k price if out of pocket)

    8yr/100k warranty on it.
    10yr/150k warranty for CARB states.


    --might want to check the 12v reg car battery first though to see if thats the issue. Pepboys will Check it free of charge.

    Edit: I just saw that your location is Isreal (mobile priuschat does not show locations, you have to click on posters name), warranty there I am clueless about, hopefully at least the 8/100.
    And pepboys?? Best of luck.
     
    #2 Blizzard_Persona, Dec 19, 2014
    Last edited: Dec 19, 2014
  3. vday

    vday Member

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    Here we get only a 5 year / 100K Klm warranty and I'm about 3 weeks away from that so guess I'll bring it in ASAP.
    Toyota offers to extent the warranty for a year (at a time) for about $80. We can do that every year till the car is ten. I plan to do that. I need regular maintenance (90K) in about 6 weeks but don't want them to tell me I'm late so I will bring it in before.
    Why would the 12v reg battery cause that?
     
  4. Blizzard_Persona

    Blizzard_Persona Senior Member

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  5. bisco

    bisco cookie crumbler

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    sounds like she's ready to give up the ghost. you can continue to drive her until the dashboard lights up. how's your gas mileage?
     
  6. David Beale

    David Beale Senior Member

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    "It can't hurt" is not quite true. It will cost you $50-$120 to have them evaluate the battery. If they find it's bad that charge may be waived.
    I doubt the battery is about to "go". The charge meter is approximate at best. Lots of things can cause it to read differently, such as changes in ambient temperature, dirty battery cooling vents, etc. etc.
    The 12V battery is charged from the traction battery (through the charger built into the inverter). If it's failing it will be a constant load on the traction battery, and -could- cause it to run a little lower on the charge scale. More importantly, a 12V battery in poor condition can "mess" with the electronics (poorly regulated power).
     
  7. vday

    vday Member

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    Thanks all
    I'll get it checked Tuesday. I don't think they will charge to check - we'll see.
    I am still using the original 12V battery so it could be that.
    As to my gas mileage - It has never been great - life time average about 40 MPG - lately about 10% down.
     
  8. bisco

    bisco cookie crumbler

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    ya, 10% could be your 12 volt. put a voltmeter on it in the morning before starting the car.
     
  9. vskid3

    vskid3 Active Member

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    Even if the traction battery is on its way out, the dealer probably won't do anything unless there's a code/warning light.
     
  10. macman408

    macman408 Electron Guidance Counselor

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    I'd second the guess that your car is just fine. The 12V battery might need replacement, but my first guess would be that everything is normal. The lower bars on the battery gauge represent less range than the upper bars (this is also true of the bars on your fuel gauge and your cell phone signal strength). So if your battery SoC is lower than it typically has been, you may see bars coming and going more frequently than you did before, even if the SoC isn't varying any more than normal.

    As to why it's low - it might just be chance, or maybe something has changed in how you're using it. Are you using A/C more, or the defrost vent output (which forces A/C on, even if the light is off)? Are you using EV mode, or feathering the pedal to keep the engine off intentionally? Are there any new or different electrical loads on the car? Turning on your headlights *might* make a noticeable difference (not on my car, but they're LED, so you'll have to ask someone else); more noticeable would be high fan speeds, a large power inverter, or aftermarket audio equipment, for example.

    Or maybe it just got low one day, and hasn't recovered yet. If you get on a highway and use cruise control to stay at a nice constant speed, it should stabilize around 60% SoC/6 bars fairly quickly.

    The battery meter on your dash tells you absolutely nothing about the health of the battery. Keep an eye on it, and look out for anything else unusual, but I would have no worries in your situation.
     
  11. Mendel Leisk

    Mendel Leisk Senior Member

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    I can't with recall ours, 2010 manufactured in August 09, seeing one bar state of charge. Ever.
     
    #11 Mendel Leisk, Dec 20, 2014
    Last edited: Dec 23, 2014
  12. vday

    vday Member

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    Went to get it checked
    They found no problem
    Said the 12V battery may go soon as it is 5 years old
    Didn't pay a penny :)
     
  13. bisco

    bisco cookie crumbler

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    well, at least you got what you paid for.
     
    vday likes this.
  14. vday

    vday Member

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    vskid3 you got it right
    The car gave a warning "check hybrid battery", then they started taking me seriously
    After a few day wait got the hybrid battery changed for free.
    Luckily I paid for the extended warrenty just a month earlier LOL
    Car sounds much better and seems fuel economy back to what it used to be3
     
    rtotheichard, Robert Holt and vskid3 like this.
  15. Garvin

    Garvin Junior Member

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    Hi vday. I have noticed my battery dropping down to one bar twice now over the last couple weeks. I also noticed that i cannot drive as far from full SOC to when the engine has to chip in to recharge. Are these the symptoms you had before your HV battery failed? I am at 85000km in a 2010 Prius. How long did it take before the warning signs and actual failure?