2012 Prius v Five: sudden 12v battery failure

Discussion in 'Prius v Technical Discussion' started by Synthetic, Aug 1, 2016.

  1. Synthetic

    Synthetic Junior Member

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    The Saga
    We've had our Prius v for a few weeks. Bought from a Toyota dealer who serviced the car (oil, filters, rotate) at 114,000 miles) before delivery. The car has been wonderful... until this week. We were on a 900 mile trip to the LA area from Texas, stopped for fuel at about 800 miles, Marino Valley, CA and when I got in to start the car it was completely dead. The day was hot, hitting 115F around Phoenix.

    From my manual readings and priuschat readings I thought the 12V battery must have failed. It was 4:15 on a Thursday afternoon.

    Lucky/Unlucky
    Luckily, there was a Toyota dealer 4 miles away. Unluckily their regular mechanics had left for the day.
    Luckily, their recommended tow co. sent a truck within 20 minutes. Unluckily, all three of us could not fit.
    Luckily, Enterprise, only 5 minutes away, sent someone to pick me up at the gas station while my wife and son rode with Mr. Towtruck to the dealership. Unluckily, I had to wait to near closing (6PM) to get the car.
    Luckily, I got the car and they gave me the "old man pity" discount and I headed for the dealership planning to pick up the familiy and luggage, continue on to Calabasas, drop our son at Pepperdine the next day, and drive back to Marino Valley to retrieve our fixed car on Friday. Lucky (again) moments after I left Enterprise, my son called and told me the service manager swapped in a new 12V and the car was working. Lucky again as I drove around the block and returned the Enterprise car just minutes before they shuttered the shop. Lucky still, Enterprise, in full old-man-pity-mode, voided my rental contract. By the time I walked out of the Enterprise office, our son was pulling in with the Prius. So, in the space of an hour and 45 minutes, we completely broke down, towed the vehicle to the dealer, Enterprise picked me up at the scene of the crime, I rented a car, returned the car, and the Toyota was fixed, all within minutes of closing times at the dealership and Enterprise.

    Cost
    $95 for the flatbed tow. I hated watching him drag our locked front wheels even the short 20" onto the flatbed. Dwayn, a Jamaican, assured us he understood "Prius" language and all was well.
    $200 battery plus $130 install = $330
    $10 tip for the Shell gas station attendent who patiently looked up phone numbers for me.
    Total $435 for this failure. My wife paid for this, and I think the Toyota dealership reduced it by $50
    because the install went quickly.

    Happy endings
    We continued on to our airbnb rental in Calabasas, washed faces, and went out for one of the best pizzas ever...
    the place even had a group of about 10 people who I think were patrons but met to play Irish songs on their violins and gutars.

    Discussion
    Our car gave us zero warning of any sort of impending failure. The Toyota dealer told my wife and son "120,000 miles and 4 years old, yes, time to replace the 12V". In my opinion, Toyota engineering needs to find a way to detect impending failures, direct dealers to inspect/replace the 12V during routine service appointments (such as this car had 6 weeks prior), or light a dashboard light at certain mileage/age to recommend a new battery. I read another story here where the Prius (non-v) drive had total failure while entering a highway, with no warning signs, and only 1 year after replacement of his 12V.... now THAT would be terrifying.
     
  2. drysider

    drysider Active Member

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    Couldn't the gas station jump start the car?
     
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  3. rdgrimes

    rdgrimes Senior Member

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    There was nothing "sudden" about the battery failure, its been planning to happen since 2012. A 4-year old battery and high temps are a recipe for failure, and failing "all of a sudden" is typical in hot weather. Unless you expect Toyota to predict operating conditions for the car, how are they supposed to predict failure? Some people replace OEM batteries every 3 years and 4-5 years for aftermarket. Keep in mind the factory uses batteries from the lowest bidder.

    Moral of this story: When buying a 4 year old car demand that they install a new 12v battery as a condition of the sale.
     
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  4. Synthetic

    Synthetic Junior Member

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    Lesson learned. BUT, who, other than seasoned Priuschat users and Prius dealers would even know to do that? That is why Toyota engineering needs to look for solutions. In all of my own decades of car and battery use, in every case, impending 12V battery failure
    came with warning signs; labored cranking, slighly dimming of lighting, hard start on cold mornings.

    Leaving owners stranded without warning is not a good formula for owner satisfaction.
     
  5. Synthetic

    Synthetic Junior Member

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    It was just a "gas" station. The towtruck driver could have given us a jump at $60 vs a tow at $95 but I was not willing to risk a failure on the way to a dealer, 800 miles from home, at closing time. For us we needed some surity. If we were in our home city we might have made the jump decision.
     
  6. Synthetic

    Synthetic Junior Member

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    Also, from now on, yes, we will install new batteries every 3 years... I just hope we don't forget. If the dealer where we purchased the car even hinted to us to consider replacing the battery we certainly would have done that. Remember this, anything that strands a motorist on the highway is a life or death event. Some things mechanical cannot be predicted or avoided, but in this instance, it would seem that the selling dealer should have given us the choice and Toyota engineering should have provided us with at least a warning. This was a preventable failure event.
     
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  7. Mendel Leisk

    Mendel Leisk Sand Pounder

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    Get a digital multimeter, read up a bit and peridocially check the battery's at-rest voltage. Get a 4 ampish smart charger, hook it up once a year or so and just let it run. Turn off any interior "convenience" lights you can, never listen to the radio in "accessory" mode, and just get biblical about accidentally leaving lights on, door ajar. Get a jump pack, test-use it, keep it charged up, always bring it (is there an underfloor tray in the hatch?). And yeah, be prepared to replace the 12 volt battery in advance of a failure, say every four or five years, at your convenience, and stay on top of prices, what batteries are compatible.

    Umm, that's about it.

    FWIW, your bill wasn't catastrophic, well maybe a bit for the states. The inconvenience is the main factor: a jump pack would dispel all that.
     
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  8. Synthetic

    Synthetic Junior Member

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    Thank you for your comments. After reading I put "replace Prius battery" on my calendar for 1 August 2019, three years out. Off to buy the smart charger. We had already assumed the steps you mention regarding no use of accessory mode. We were leaving the headlight switch in AUTO mode, which left the lights on for a minute or so after exiting the car.
     
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  9. rdgrimes

    rdgrimes Senior Member

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    Depends on what battery they put in there, but it could last 6 years even. The caveat here is the OEM battery, which is crap.
    Living in the desert for 20 years, I've seen quite a few batteries die in the heat and there's almost never any warning. They start fine one minute and then die completely. Welcome to hot places. Heat is actually worse for a battery than cold cranking. Hybrid systems don't crank the ICE. The good news is that because the battery is in the back instead of under the hood it doesn't get quite as hot. The traction battery fan even blows air past the 12v battery under the rear deck, although its warm air.

    But these are puny little batteries that aren't meant to do much of anything besides boot the computer and run the cabin lights when the system is off. Hardly more than a motorcycle battery. Forget about people telling you that you can tell by checking the resting voltage. It might be low or it might not. But you can start a hybrid system with a handful of D-cell flashlight batteries.
     
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  10. Mendel Leisk

    Mendel Leisk Sand Pounder

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    Heat punishes them, then they die in the cold?
     
  11. bisco

    bisco cookie crumbler

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    because you bought a used car, you have no idea how the 12v was abused. there is no need to buy a new battery every 3 years. if you educate yourself, your battery can last up to 8 or 9 years.

    toyota has basically admitted the problem by moving the battery to the engine bay, in the gen 4.
     
  12. drysider

    drysider Active Member

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    Another option is to keep a 12 volt source in the car. I use a small lithium pack that is good for 15 amp-hours. You could get by with 8 D cells if necessary.
     
  13. Synthetic

    Synthetic Junior Member

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    Also, our 12V completely died, or seemingly so; everything lost complete power, no dome light, no dash lights at all. I left the car unlocked or otherwise would have had to use the metal key to get insidWould a smart charger have helped?
    I think this idea also makes sense,
    I think we will try the 12V lithium pack. Any wild guess on how far you could drive with one of these? Do they hold their charge over time while stored in the car? Would you connect the pack across the Toyota 12V battery terminals, or disconnect the bad 12V battery and connect the lithium pack to the cables? I just looked at my receipt from Moss Bros and the 12V they installed has a 7-year warranty. Does not state if it is prorated. Frankly, we are still living in some fear that a future failure could result in far worse consequences, but if circumstances are similar to a gas station failure then we could probably avoid the tow and drive to a dealer. Thanks.
     
  14. bisco

    bisco cookie crumbler

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    if it's toyota oem, it's 2 years full replacement, then prorated. fear is your enemy, not the battery.:)
     
  15. Mendel Leisk

    Mendel Leisk Sand Pounder

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    The 12 volt battery is mainly used to start the car, nothing beyond that. Well not quite: a failing 12 volt will continue to tax the car's charging system as the car runs, and can be the source of decreased mpg and buggy behaviour.

    Any jump pack requires periodic recharging, particularly after use.
     
  16. drysider

    drysider Active Member

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    It is just for jump starting, not for constant use. Once the engine is going, the HV battery will supply the necessary 12v thru the down-converter.
     
  17. Mendel Leisk

    Mendel Leisk Sand Pounder

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    Similarly with a conventional car, once it's jumpstarted, the 12 volt battery is little needed: the car's alternator is constantly supplying voltage and keeping the (ailing) battery's voltage up.

    But stop and try to restart the car, if the 12 hasn't been revived by the charging while the car was running, you'll continue to have starting problems.
     
  18. Robert Holt

    Robert Holt Senior Member

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    Funny you should say that! I have a lithium-ion jump pack as my Plan A backup for 12-volt battery failure, but the Plan B fallback is a pack of 9 akaline D cells in series with alligator clips to jumpstart our Prius. I have not tried Plan B, have you?

    But I also replaced all interior lights with LEDs, which reduces power consumption , particularly if lights are left on accidentally.
     
  19. rdgrimes

    rdgrimes Senior Member

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    No, but I replace 12v batteries on spec every 3-4 years. If one ever gets completely drained, its gone the next day.
     
  20. Synthetic

    Synthetic Junior Member

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    Related: upon total failure of our 12V, even though our car was unlocked at the pumps, my son could not open the rear hatch even though the doors were unlocked and could be opened. I did not go to the Toyota dealership with the car, but I asked our son if he saw how they opened the rear hatch and he (thinks he) saw them "pull a fuse" under the hood, then open the hatch. This doesn't make logical sense to me. Anyone want to comment?
     
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