12V Battery warning and sudden shutdown on the highway

12V Battery warning and sudden shutdown on the highway

I was driving my wife and son back from his final JO water polo game, was just merging onto 101 Southbound. When I punched it to merge into traffic, I got the 12V battery warning, and then the car SUDDENLY AND COMPLETELY SHUT DOWN. No power at all. Thank God I was in the right lane and made it to the shoulder.

Ironically, I'm about 1 mile from the Tesla headquarters, and roadside assistance said it would be a 25 minute wait (this was after at least 10 minutes on the phone already).

WTF Tesla! A car should not just shut down that quickly without any warning - very dangerous! Obviously there is a single point of failure in the electrical system that just simply shouldn't exist. This is a total failure in engineering!

I see that others had a good experience with customer service. My experience is anything but good right now!

Tesltoronto | 5 août 2014

I think the point is not whether ICE cars fail or not. I am not sure why when anyone talks about a problem they are always ridiculed.

Let us face it. The 12V problem seem to be there from the beginning. It was initially blamed on the battery vendor, bad batch of 12V batteries, etc. But the car is in its 3rd year of manufacture. So those excuses are no longer valid.

I think Tesla, being a proactive organization, should seriously look at resolving this issue once and for all before it goes out of hand.

May be there is a common cause to all the 12V issues. Perhaps people are not charging the car every day or something like that. It would be great if Tesla comes up with a solution quickly - since this has taken far too long to resolve.

NetWatchR | 5 août 2014

@hpjtv - The problem wasn't the type of the original 12V battery but the quality. Any battery that's built incorrectly will fail. And that's not to say that Tesla intentionally cheaped out on the 12V, it simply could have been a bad batch from the vendor.

Mark E | 5 août 2014

@mrspaghetti & @Cindy I II III

LOL, it sounds worse than it is - I've been driving for 33 years, and well over a million km. I've owned cars that never failed, and some that failed multiple times - eg the one that broke a timing belt tensioner on the way to getting serviced. It's problems were often after getting serviced, I changed dealerships and the car was better.

I've been stuck a few times, but also rescued others - I have pretty good mechanical knowledge and always have at least a basic toolkit in any car. I'm also on the road a lot having been in iT field support, consulting and then IT sales for 25 years, plus living in Australia with family up to 1500km away in various directions.

14 failures over that time isn't all that bad less than one in 2 years :)

J.T. | 5 août 2014

@bobgriswold I'm sorry for your frustration and I know the fact that it did happen is a lot more important than why it happened or if it is more likely in an EV than an ICE.

Has service confirmed an actual 12v failure or was it perhaps the dc to dc connection or other contactor failure between the batteries?

PBEndo | 5 août 2014

It seems you and I had different problems. My problem was the main pack, even though the alerts indicated the 12V was the problem. Since my 12V was still working, I was able to put it in tow mode without issue, once I realized it was necessary. In addition, my main pack was actually still working, it only failed for a moment.
I now carrying a small 12V spare battery in the frunk for emergencies, one of the small sealed ones used in backup power supplies for computers and alarms systems. I haven't needed it yet, but I think it would be powerful enough to power things up in an emergency. Of course, I have to remember to keep it charged.

Bighorn | 5 août 2014

It's easy for us to be flip and snarky as we lounge around our yachts and manses in our smoking jackets while the OP recently faced the gritty reality and trauma of a major breakdown which threatened his sense of security and the safety of his family. It's natural for us to practice the art of oneupmanship regaling others with our worst automotive memories. It's no wonder there's not been a meeting of the minds here, which included the OP. If that's distasteful, I apologize for my part in it, as well as joshing about the surname that brought back memories of Chevy Chase's onscreen travel persona.

What's been equally unproductive is the suggestion that this breakdown was the result of the 12V battery and not something more insidious and difficult to address, be it the contactor or something we don't quite understand. The lame-ass panacea of 12V redundancy being the obvious course of action (and I'm not calling anyone out, but it just seemed to be the tack this thread was taking) is intellectually flawed. Far greater minds are working on the problem, and based on the number 12V battery upgrades we've witnessed, I don't think there's an issue over lack of trying or an unwillingness to invest resources towards its resolution. This issue has to be right up there with fire prevention/battery intrusion on engineering's to-do list. It's a potential make or break issue for TSLA's survival, so they will figure it out.

I live over 400 miles from a service center, so the concept of being stranded is a lot more palpable than for someone who breaks down one mile from Tesla central. I imagine assailing the service department based on a 25 minute wait might have been what triggered some of the many defensive responses. I hope after your car was taken off for the remedy, the concern shown for your situation by service and a proper explanation of what happened and how they're working to fix it will mitigate the bad taste this left after so many years of being an early, supportive disciple.

P.Mac | 5 août 2014

I pick up my S85 in lateSeptember, so I have no personal knowledge in this area, but it is easy to sympathize.

I want to emphasis easy particular facet of OP's problem - the "complete" shutdown of the vehicle. As other posters have mentioned, a complete shutdown turns everything off. I suspect that means no access to the frunk-opening controls on the center screen. Is there a manual opening mechanism for the frunk? If not, how could we even accecc a spare 12 volt?

Further, in a complete shutdown we appear to lose access to the always valuable ability to simply push a vehicle, whether it is off of a busy road or out of the entry to a parking lot. I wonder if Tesla could give us, or any road-side service person, the ability to tap into a dead main control screen to enable us to access basic emergency controls such as frunk opening or tow mode. Perhaps a special USB port that could provide access to a smart phone. Or maybe even appropriate software modification to allow such access through the existing USB ports. Would it be possible for the main screen to run off the power through the USB from the smart phone, briefly, to allow access these emergency controls. Perhaps using the security controls already available in the remote app?

I do not know anything about the wiring or logic of the a Tesla system, but a complete lack of knowledge on a topic has never prevented me from making a suggestion.

P.Mac | 5 août 2014

One other thought. This topic seems like a good candidate for switching to a "private" thread.

jai9001 | 5 août 2014

I recently had my 12volt battery replaced prophylactically. Car was driving fine, but car would not enter "sleep" mode and my vampire drain had increased substantially.

I was told by the ranger that Tesla engineering was in the process of completely "redesigning" the way the 12 volt battery worked. The interim solution was to switch to a deep cycle battery, but a more definitive solution was coming.

Bighorn | 5 août 2014

Some people have had luck boosting the car with the 12V terminals behind the plastic nose cone, others not. Some people have had luck restarting the car after it "died" in order to move it.

tes-s | 5 août 2014

Good thing it was not on the way to the final JO game! Did that happen last week? I thought the boys finished a week ago.

J.T. | 5 août 2014

@P.Mac After many long threads which debated the option of making "problem" threads private it has been pretty much agreed that it is not a good idea.

Imagine if you were a potential buyer and you saw that post title and the thread was private. You would never read the resolution.

The car will have problems. All cars do. No reason to try and hide it. The way Tesla resolves the problems is what continues to set them apart from the ICE dealers and keeping the threads open allows everyone to see that.

The only reason I would ever make a thread private is if I was seeking advice from experienced owners only. I only wish that there was a "really private" designation to filter out reservation holders.

SCCRENDO | 5 août 2014

I thought the 12 volt battery was solved. I had a first generation battery (vin 77xx). Never had a problem. Mine was prophylacticaly swapped out at my second annual service. I thought that there was a service bulletin. OP doesn't state whether this was an old original battery. Also how many on this board still have the first generation battery and has anyone here had issues with the newer battery.

jjs | 5 août 2014

Bighorn - Although you did not want to call anyone out, effectively you did.

We mostly agree. We agree that the primary concern should be for the safety of bobgriswold and his family. We agree that the service center should quickly work on and hopefully resolve the issue. We agree on best wishes to the OP and the best of luck moving forward. We also agree that minds much more capable than ours (at least mine) are working on the problem.

However I stand by my statements regarding the simplicity of the Model S design allowing for more redundancy than we will ever find in an ICE vehicle. I also stand by my statements regarding Tesla's willingness to listen and improve.

Early on in this thread I stated "...if it was the 12V battery..." leaving room for it being another part that caused the problem. I do not know if it would be better to fix the defective part or to build in redundancy. I will leave that to the experts. My statements were always meant in the generic sense and not specific to any single part. To the extend I did not convey that bad. I do however very much disagree that the general concept is intellectually flawed.

mrspaghetti | 5 août 2014

@SCCRENDO - we don't know for sure that the 12V is the actual cause of the malfunction experienced by the OP

@Bighorn - I think what you're perceiving as snarkiness in some responses is not a response to the incident per se, but rather the implication that such a failure is somehow unique to Tesla. OP stated the following:

WTF Tesla! A car should not just shut down that quickly without any warning - very dangerous!

Reality check - I paid over $100K for this car. How many of you out there have ever had a $100K+ car less than 2 years old suddenly fail??

Thus, many people have answered his question with accounts of how their vehicles have suddenly and catastrophically failed. So yes, Tesla can improve this situation, but the OP should understand that Tesla is not more failure-prone (and probably less so) than any other vehicle. Furthermore, he's been astronomically lucky not to ever have experienced this previously if he's been driving for any length of time. And clearly he has never driven with Mark E.

Bighorn | 5 août 2014

You know I love you and you'll have to believe that I didn't go back and see who I might offend. Almost guaranteed, this was not a 12V battery problem--it was almost certainly the contactor and my limited mind can't conjure how having a second 12V would have remedied that situation. Is it possible that it could have it kept the car alive enough to shift into neutral/tow and move? I don't know if that's possible or if the car is de-energized as a safety measure for rescue personnel. I wouldn't mind a lithium 12V if the lead-acid battery is a problem. I wouldn't mind two if it's going to solve something. But, in this instance, it seemed like the thinking was going down the wrong path. I apologize if you took my criticism to heart--I was just trying to re-direct to what likely happened, and I don't think the 12V was the culprit. I have a July '13 build and have had the 12V replaced twice for no apparent reason. I thought the first time was to get a deep cycle, though I think my car came with one. What the deal with the second replacement is anyone's guess. It was at my annual service and I don't think the car let on that anything was amiss.

I guess you'll have to allow for some poetic license:) I too piled on with my example of stranding, but it clearly did not help Mr Griswold feel any better about his plight. A $100,000 benchmark does not change physics in this world and the reality is that even million or billion dollar vehicles suffer catastrophic failure (see Challenger O-ring seal). Exotic and prototypical cars are probably more prone to these things and we don't wish to feel any angst headed out on the open road in our new super car, but there is measurable risk in every action we take. If there's any consolation for this type of failure is that it's probably covered under the unlimited 8 year battery warranty. I'll feel better when it's all figured out, if it's not already, and properly addressed.

J.T. | 5 août 2014

In situations like being stranded there isn't much solace in knowing that it simply shouldn't happen, not to any well maintained vehicle. But it does, and getting the incidence rate down to fractions of percentages is the best we can hope for. Murphy will always have his way, but maybe not as often.

AmpedRealtor | 5 août 2014

There is no reason why the failure of a 12v battery should immobilize a vehicle that already sits on top of an 60-85 kWh battery pack that is also responsible for recharging the 12v battery. The redundancy is obvious - either use the main pack for all electrical needs, or have the main pack act as backup in the event of a 12v failure.

I'm obviously not an engineer, but it seems odd that a car with so many powerful batteries can be brought to its knees by a stupid 12v.

Mark K | 5 août 2014

Bighorn, jjs, et al - it almost certainly was not the 12V cell in this case, but likely the main HVIL contactor (which is powered by the 12V cell).

The common notion though, is that if either one of those single choke points has a failure, the whole power system goes offline.

This "deadman trigger" arrangement is a very effective safety feature in a crash, but it also carries a finite risk of unwanted shutdown.

Reducing or eliminating single point failure risk is a good thing, and I think Tesla will be able to do it. I believe they can get this risk very close to zero with further creative engineering. SpaceX is very focused on this, and their extraordinary launch record is testimony to it.

For the OP, the salient feature right now is his fresh brush with danger and the fracturing of confidence in his in enthusiasm for his EVs. That is regretful, but I believe it will heal with attention to the matter, and a return to solid performance.

There is a natural perception bias at work here too. If you ask someone about car crash risk the day after they had a wreck, their answer is different for a while. Then it goes back to normal with time.

In pure, coldly logical terms though, the way I would get over such a disappointment is to ask whether my statistical risk is less in any other car.

My engineering opinion is that this car has a lower risk of catastrophic power failure than any gas car. The risk is still nonzero in a Tesla, but it's worse in conventional cars. This advantage is inherent in the architecture.

That is why, at the end of the day, all of my family is in Teslas.

Mark K | 5 août 2014

AR - your assumption is correct that a redundant 12V cell would have allowed the parking brake to be released.

That is evidenced by the successful jump procedure from tow truck.

Bighorn | 5 août 2014

Thanks again for another very incisive post using facts to illuminate the discussion.

Bighorn | 5 août 2014

As to a second 12V being necessary to release the parking brake, is there a way to keep it charged as well as isolated from the main battery pack such that it doesn't suffer a similar fate to the present 12V battery? Does it make more sense to have a manual over-ride of the parking brake, since in either situation, the car will have no power to move other than brute force?

Mark K | 5 août 2014

Yes, it's possible to have an independent charge path for the backup cell - not expensive, and desirable. What I suggested on a past thread was a smart fail-over circuit that would handle charging and switchover.

As to parking brake, your idea is good, but it's not simple to operate by hand, since it's an electrically-operated gear motor drive (likely a worm drive so it can't loosen when powered down).

One way to do your idea is to provide a hole in the caliper housing into which an Allen key could be inserted to manually crank it open. Some Mercedes convertible tops/ sunroofs had that.

But for most consumers, a second power circuit that could move it for you would be more friendly.

Brian H | 5 août 2014

By all accounts, on level ground the MS in neutral and tow rolls very easily. Not a whole lot of brute required.
Powerful machines and people are a problematic mix. Murphy can get murderous. People drive anyway, "knowing" the risk.

jjs | 5 août 2014

Bighorn, you have been too level headed and beneficial to the forum for me to have taken offense. I didn't. I did however want to make the point the Mark K. made more eloquently than I. (He often does that and it's getting REALLY annoying. :) )

The type of failure was serious. It can be addressed. It should be know....what Mark said.

Bighorn | 5 août 2014

I agree it's easy to move the MS in neutral on a LEVEL surface--otherwise you're at the mercy of gravity, so there's ~ a 50/50 chance your car goes the way you'd hoped.

I appreciate Mark and jjs's thoughts on an auxiliary battery. I imagine the engineers are not ready to give up on the possibility of creating a single battery solution. Fixing the contactor would be the ultimate outcome.

bobgriswold | 5 août 2014

So, it turns out that my problem was indeed the contactors in the main battery pack. Tesla has replaced those contactors now in my original battery pack and are testing it now. I am supposed to get my car back tomorrow.

Incidentally, I have a very early VIN (019XX), and my 12V battery was indeed replaced about a year ago, so this happened with the new 12V battery on board.

My biggest issue here, which may have been buried by my temper when I wrote my original post, is the suddenness and catastrophic nature of the failure. No warning at all, just sudden shutdown with no ability to even push the car. No matter how you cut it, and completely regardless of whether ICE vehicles have this problem or not, this is a situation that should not happen and absolutely can be prevented with basic & proper engineering.

Bighorn | 5 août 2014

I think some people have gotten new battery packs when the contactor went, because supposedly they weren't easily accessible--you are simply having the part replaced and keeping your battery?

bobgriswold | 5 août 2014

@Bighorn - yes, they put new contactors in my original battery and reinstalled it in my car. I did not get a new pack. I asked for one, but they said that the factory has fixed my pack and it is "as good as new." I asked about the warranty, whether the battery warranty would restart from today, but the service rep said that all 85's have 8 yr. unlimited mile warranties, and since mine was repaired, the warranty doesn't start over. I'm not that happy with this, but I can understand the business reasons behind it.

@tes-s - My son is 10, and he competed in Session 1 of JO's with a U12 team (they got the silver medal in the Bronze division), and he competed in Session 2 last weekend with the U10 team (U10's are mixed boy-girl). They got 4th place in the Gold division there. We were returning from his last game when this happened.

Bighorn | 5 août 2014

Perhaps one drawback of having it fixed at the factory--they could fix it whereas a service center might need to do a battery swap. Not saying one is any better than the other. Did they give you any reassurances about the issue and whether it's been improved upon in the updated contactor?

Mark K | 5 août 2014

Glad your car is getting fixed.

There have been comments that the contactor part has been changed to address rare issues that have occurred with some early vin's.

Given that this is the only time you experienced this defect in 18 months, and they've now installed the latest spec part, let's hope your go-forward experience will be the same as all the other owners who've never had this problem.

To gain confidence that it's solid, there are some tests you could do. Go to a safe area that has an incline, and try flooring it several times going up the hill. Hopefully, it truly is fully resolved.

As to what TM can or should do, a few comments - although engineers try to avoid single point failure risks, this issue is not as basic as it may seem. The safety system is a complex network of links in the chain, and firmware to operate them. It is possible to cause other problems if redundancy is added, and these design choices are always about balancing objectives.

In principle, it should be possible to have a fallback set of contractors - even a partial set that gets you reduced power to limp along. But covering all the bases is nontrivial and takes engineering time. I'm sure Tesla is studying this data, and planning how to mitigate the risk. But we shouldn't expect this very quickly, given the validation required to get it right.

My summary point is I don't think Tesla's engineering was lax at all, but it's always possible to improve something.

Everything, and I mean every single thing in the world, can fail. Even with a super low failure rate however, If you happen to be that one in a million, it is unnerving. Reducing this as much as possible by continually improving the design is desirable.

It is intrinsic to Tesla's culture that they are motivated to do this.

I think they will.

hpjtv | 5 août 2014

@bobgriswold Your vehicle was taken in for warranty cause of a battery fault. It carries an 8 year unlimited miles warranty from the date you purchased it. Why in the world would you think they should give you a brand new 8 year warranty from the date of the warranty repair? If that was the case, your warranty could potentially last forever. I've never heard of any product doing that.

riceuguy | 5 août 2014

I had the engine fall out of a $60k Mitsubishi 3000GT Spyder at less than 1 year old. Talk about stopping suddenly and not being able to start again! They said the engine mounts weren't installed properly at the factory...the engine was damaged and the repair took weeks. This can definitely happen in a new, expensive ICE vehicle!

bobgriswold | 10 août 2014

@hpjtv Your logic is sound, until you get to the extremes - imagine if 2 days before my warranty ends my battery pack completely fails and I get a new pack. Would that new pack only have 2 days warranty? And if it failed 3 days later, I'm out of luck?

Honestly, I think what would make business sense is to have Tesla warrant any new component or work they do on a car for 1 year or until the end of the original warranty - whatever is longer. If that were Tesla's policy, then the work they did on my battery would be covered only until my original warranty expires since it is further out than 1 year. Either way, I'm fine with what Tesla did for me this time.

Only Trons | 10 août 2014

@bobgriswold: I'm sorry you had to go through this and I can certainly understand your frustration. I'm glad that your family was safe. I am certain it was a very scary moment when it happened.

I have had a couple of instances of an ICE car (not >$100K) stopping suddenly and without warning. I was on the highway in California after just having visited my grandparents in Fremont (when the current Tesla manufacturing plant was a GM plant, and not a NUMMI or Toyota plant!!!) The engine in my MG just stopped dead cold. I immediately depressed the clutch and was able to coast over to the right side shoulder. No cell phones in those days!!! I walked some distance to a gas station --- can't remember how far, but when I tell the story to my grandkids it is always at least a mile or two, all uphill, and with snow on the ground!!!. Called my grandfather and he came with a big rope. We towed the car about 20 miles back to his home using a rope! After crawling around the car for an hour or so I discovered that the fuel pump safety switch had given out. I wired around the darn thing and got the car started again and made it home to southern California. The other time I was with my brother in his old VW squareback. I seem to recall that the cable from the accelerator pedal to the throttle snapped. The engine immediately went to idle and we coasted over to the side of the road. We figured it out. Fortunately we were able to rig up a temporary line to the throttle and limp back home about 100 miles or so pulling the temporary line by hand.

Again, glad to hear your problem has been corrected. And thanks for being one of the early adopters that paved the way for me. My VIN is 8XXX so I am benefiting from folks like you.

PaceyWhitter | 10 août 2014

Just the same as if the original pack failed three days later.

Mark K | 10 août 2014

@bibgriswold - Bob, just want to check something -

Had your Model S been serviced shortly before your power loss experience?

bobgriswold | 13 août 2014

@mark k: as a matter of fact, it was serviced a couple of weeks before this incident. I didn't even think that would be related in any way. I'm curious - why do you ask?

nickjhowe | 17 août 2014

OK @Mark K - very intrigued by your question....

J.T. | 17 août 2014

@bob @nick Mark K asked the question like he was House M.D. This should be good!

Mark K | 17 août 2014

Reason for asking was that one other such incident happened one day after a service visit.

Could be pure coincidence, but I work a lot with firmware-based systems design, and when anomalies arise, I've learned to ask what just changed. It's uncanny how often that points to the cause.

In your case, it was 2 weeks, which is a pretty long time. I assume you had plenty of hard acceleration events before the failure event.

Insufficient data to conclude anything here, but the next day juxtaposition case was notable. Sometimes firmware-based activity can behave unexpectedly if initial conditions are disturbed.

Service diagnostics can do things that are not typical of routine driving. Theoretically that should all be reinitialized after diagnosis, but there is a nonzero possibility of some residual state.

In any case, the HVIL contactor issue is under review and they will find the cause. At the moment, we don't know whether the cause is defective contactor hardware, an oddball state the firmware got stuck in, or something else. They need to study the batteries that manifested it to understand and eliminate any residual possibility it could ever happen.

In the meantime, it looks like there's a very low incidence of this failure, so it is unlikely most people will ever experience it.

Since it works well for the great majority of owners, it is likely some small subtlety needs adjustment - like that 50 cent washer in the case of the reduction gear assembly issue.

It's important that they find and fix it, and I'm confident they will.

It will be interesting to hear their final conclusion of the cause.

Sudre_ | 17 août 2014

Yes I have had a car less than two years old just suddenly shut down. It was the camshaft sensor. It does happen.

pdmckinnell | 15 septembre 2014

Just happened to me with my 3 month old Model S 85. Fortunately was in a parking lot when it happened

pdmckinnell | 17 septembre 2014

Update on my post from 9/15/14. Car was picked up by Tesla on 9/15 and just got it back (they dropped it off at my house.) The issue was "the HV pack was disabled and was not floating the 12V." They replaced both the 12V battery and the HV battery. All in all, not to bad. Two days without the car but they handled the issue quickly and professionally.

iblorico | 29 août 2019

@bobgriswold, I have similar problem now. Shutdown 3 times already and they still can't find out the main problem. What happen to your vehicle now?