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Suspect my 12V battery has died

Discussion in 'Prius v Care, Maintenance and Troubleshooting' started by Krellan, Jan 6, 2016.

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  1. Krellan

    Krellan Junior Member

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    I have a 2012 Prius v Five, without ATP package. It was parked outside, on a cold rainy day. Went to start it.

    To my surprise, these four idiot lights lit up: yellow skid icon, yellow "check engine", yellow "(!)" icon, and yellow hybrid system icon (car with "!" symbol through it). Tried turning it off and on again, it persisted. Tried driving the car, but it barely had any power.

    The gasoline engine ran continuously, without stopping after warming up, as it usually does. The car struggled to climb uphill until I could find another parking space. I managed to achieve a top speed of 8 MPH by flooring it! Obviously, something was very wrong.

    So, after reading up about it here, I suspect it's the 12V battery. Toyota, unfortunately, uses a nonstandard battery that is of an unusual small size. A shame they did this, I wonder if it was a size or weight consideration that made them use a nonstandard battery? And why is it buried in the trunk, and not under the hood like it's supposed to be? Anyway, I took some measurements.

    Car completely off, measured at battery terminals with voltmeter = 12.3 V without load, 11.8 V with load (headlights turned on with high beams).

    I used the cheat code to obtain the other measurements directly from the display. On my model, the correct cheat code was to hold in the "Car" button by the center display screen, and while doing that, flick the headlights on and off three times. That worked! I entered Maintenance Mode. I then chose Function Check, then Vehicle Signal Check, to bring up the battery voltage reading.

    In "ACC" mode (hit Power button, without hitting brake pedal, once) = 12.1 without load, 11.5 with load.

    In "ON" mode (hit Power button, without hitting brake pedal, again) = 11.9 without load, 11.4 with load.

    In the normal "Ready" driving mode (hit Power button, while holding down brake pedal) = 14.5 without load, 14.5 with load.

    The voltage looks good in "Ready" mode, which tells me the alternator (or equivalent thing in Prius that keeps the 12V battery topped off while the gasoline engine is running) is OK.

    Is this normal, or does this correctly indicate a dead battery?

    Any good aftermarket batteries available, or is the Toyota dealer the only place to go?

    Thanks!

    Josh
     
  2. 48mpg

    48mpg Member

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    I know on the gen 2's anything under 12 volt is considered bad ...they only last about 4 years
    I have found the optima yellow top is a very good replacement and can be found on amazon for around $160 with free shipping.
    stores like auto zone are near or over $200
     
  3. Air_Boss

    Air_Boss Senior Member

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    We did the Optima replacement on a precautionary basis on our early '12 v.
     
  4. bisco

    bisco cookie crumbler

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    hard to say without a load test. if the car started, then the 12v is good enough to fire the computers. if the engine won't shut off (maybe) there is an internal short in the battery, or it could be something else. you might want to have the codes read.

    there are a few alternatives to the oem 12v. optima, as air boss mentioned. exide, duracell, maybe others. check around at auto parts and battery stores, or on line.
     
  5. rjparker

    rjparker Tu Humilde Sirviente

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    I would suspect something else, maybe in the Hybrid system that has a longer warranty. Take it to the dealer. Your HV battery, it's fuse, the inverter, it's power transistors, etc or caps could be bad. The inverter system had a software recall to prevent failures without which yours may have gone. All guesses but the 12v battery won't start the car if it's bad and even if jumped the car would run ok after. A crosswired jump could cause electronics failure, hybrid and otherwise.
     
    #5 rjparker, Jan 6, 2016
    Last edited: Jan 6, 2016
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  6. Krellan

    Krellan Junior Member

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    Thanks for the advice! The car is at the dealership now (it was easiest to just have it towed there, plus they have the most resources to troubleshoot it).

    Turns out there's more to it, and it wasn't just a simple battery failure. Will find out more, when they're done looking at the car.

    Regardless, I'm looking at getting this battery: DS46B24R YELLOWTOP® Prius® Auxiliary Battery 8171-767 | OPTIMABATTERIES

    Josh
     
  7. bisco

    bisco cookie crumbler

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    if you go with it, or any battery for that matter, if it isn't 13+ volts when you get it, trickle charge it until it is, before installing.

    btw, your oem battery may still have some warranty, not sure.
     
  8. Krellan

    Krellan Junior Member

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    Talked to a local battery shop that's also a pinball arcade :)

    The pro there recommended Deka batteries instead of Optima. Optima used to be good, but quality has gone down recently, he said. Luckily, he had some of the special Prius batteries in stock. Asked him to put one on the battery tender for me, that way it will be fully charged when I go to pick it up tomorrow.

    And, it turns out that it wasn't the battery that was at fault!

    It was the hybrid IPM. It died. Luckily, it was still covered under an extended warranty I didn't know I had! My Prius has 90K miles on it, which I thought was beyond all warranties, but evidently it's covered until 150K miles! Nice, because the IPM is a very expensive part, I heard.

    Also, while inspecting it, they found a small oil leak from within the timing chain cover, so they redid the sealant on that, which is rather cool.

    So, now it drives again, and I'm happy with it, but will still replace the battery because it's been a while and I want to upgrade to a stronger aftermarket battery anyway.

    Josh
     
  9. EZW1

    EZW1 Active Member

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    okay... forgive ignorance here... what is hybrid IPM?
     
  10. Lucifer

    Lucifer Senior Member

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    In the affected vehicles, the IPM is equipped with transistors that have a higher operating temperature than the solder attaching them can support, damaging the transistors. If this occurs, warning lights will appear on the dashboard, the vehicle may enter a limp-home driving mode, or the hybrid system will completely shut down, causing the vehicle to stall.

    To resolve the problem, dealers will install a new IPM at no cost to the vehicle owner. The recall begins at the end of September, and does not include vehicles that have already had their IPM replaced under an earlier recall (11V342). Owners with questions can contact Toyota at 1-800-331-4331, referencing NHTSA recall campaign ID number 13V396.
     
  11. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    Yes. Once the car's running, a weak 12 volt battery wouldn't be causing the behaviours you described.

    @EZW1 : IPM means the inverter's computer. Nowadays, one consise word is never enough; it has to be fluffed up to three, then distilled to an acronym. I had no clue, looked it up, found this: the inverter Intelligent Power Module.

    Inverter IPM - 15 year Warranty Enhancement ZE3 | PriusChat
     
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  12. EZW1

    EZW1 Active Member

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    Okay... now I get the picture. Thx
     
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  13. mikefocke

    mikefocke Prius v Three 2012, Avalon 2011

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    Can anyone tell us the date of manufacture range for the IPM extended warranty on a v?
     
  14. ChapmanF

    ChapmanF Senior Member

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    In case a little background/history helps illuminate why they sometimes come up with new highfalutin' names for things ... in Gen 1, the inverter basically had six big transistor bridges in it, that was about it. Them and the cooling system for them, current monitors, big capacitors, but mostly just big switches. And all the control of when those switches turned on and off ... to the instant, in time with the motors spinning n,000 rpm ... was done by the HV computer, under the carpet in the cabin. It had to directly watch the motor resolver signals (the resolvers are able to report back the rotor position to one part in 4096 of a revolution, and keep it up at the speeds the motors turn), and the HV computer, based on those positions, sends direct signals to the inverter to turn each of those transistor bridges on or off in perfect sequence with the rotation of the motor. Without the HV computer constantly sending those switching signals, the motors and transaxle would just be paperweights.

    In later generations, as I understand it, they moved more of that position-following and timing logic into the inverter itself, so a later generation HV computer can just send the inverter a message like "hey, need about 150 Nm forward torque out of MG2" and the inverter will make it so, and keep it up until the HV computer tells it to do something else. So, it went from having dumb transistor bridges that had to be told at every instant whether to be on or off, to having ... intelligent power modules. :)

    -Chap
     
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