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12v Battery

12v Battery

So I came across a comment on a different thread about how a 12v battery died in a 3 day old X, and I was concerned about this. If your 12v battery dies, is there a way you can get your car running again on the road, or are you forced to wait for a tow truck? I mean on an ICE car, you can obviously just pop open the hood and jumpstart your car, but we've got a frunk instead, so what can you do in that situation? I saw that on the old S, you could pop off the nosecone and attach a jumper cable behind there, but obviously we don't have that option now. Is there any warning that your 12v battery is low, or does it just happen unexpectedly? Thanks.

eric.zucker | 9 août 2016

The manual says how to get to the 12V terminals in the frunk. Alternatively you could recharge it through the 12V sockets.

hami05 | 9 août 2016

@eric -Hey man, I read about your accident, and happy to hear that you're okay! Thanks for the tip though, I'll look into that. Any warning light that comes up when the battery is close to dying?

eric.zucker | 9 août 2016

I don't know for sure but would definitely think so.

hami05 | 9 août 2016

Okay thanks, I think I'll just ask my DS when I pick up my X in two weeks. Also, could you direct me to what page in the manual I can find how to get to the 12v frunk terminal?

eric.zucker | 9 août 2016

Look at the First Responders Guide, it's worth reading end to end.

hami05 | 9 août 2016

@eric.zucker Will do, than you for the advice.

eddiemoy | 9 août 2016

if your 12v is dead, the only thing you can do is jump it to get your car on the flatbed. you cannot drive it. it is the same with a regular car. if your 12v is completely dead same thing on ICE.

hami05 | 9 août 2016

@eddiemoy I see. Well do you happen to know if there is still a warning that pops up to let you know that the 12v battery is running low? I came across some old forum threads where people talked about a warning popping up, and was wondering if someone could confirm that the new cars still give one. If no one is able to confirm this, I'll just ask someone at my service center.

Jean PierreD | 9 août 2016

on the model S you would receive a warning message on the dashboard

rossRallen | 9 août 2016

@hami05 - let us know what you find out. The SC can enter a code and check the state of charge and voltage on your 12V battery. Drivers can't get any information except, maybe, an imminent failure. I'd like to see the state of charge and voltage display on the instrument panel along with tire pressures.

eddiemoy | 9 août 2016

these new issues on the model x is strange. i did have that one issue where the battery didn't warn and it turned out to be a bad contactor on the model s, but think the new software warns since i did get the low battery 12v battery warning and it mention getting it fixed soon... i don't know exactly what the issue with the model s 12v batteries are. i've so far seen a few posts about it, i'm thinking it is a few bad batteries out there in the mix. i would assume the model x would also warn if it had a chance, but if they get no warning which is what i'm reading, it must be some really weird issue with the battery where it gets drained and dies quickly, not in a slow death like the inital bad batch on the model s'.

hami05 | 9 août 2016

@Ross will do, but I won't be making a visit to my SvC for about 2 weeks. That's really strange that they don't let us check the status on our own, hopefully they can add that in a future sw update, maybe even the 8.0 update.

hami05 | 9 août 2016

@eddiemoy yeah I'm hoping that it is just an issue with defective batteries and under normal conditions it probably does give sufficient warning in advance. I mean it would be pretty ridiculous if Tesla expected you to just drive and have no clue that your car may randomly die at any given moment on the road.

Dcp9142 | 9 août 2016

Having replaced the 12 volt on my three year old Model S, I can state reliably that you get several weeks of warning when the 12 volt is going bad. The kind of sudden catastrophic failure messages about 12 volt are nearly always caused by an entirely different set of failures that just look to the monitoring software like a 12 volt failure.

However, it seems very odd that Telsa does not make a high reliability lithium ion 12 volt.

jdrand01 | 10 août 2016

Hey guys, that 3 day old MX was mine. I was driving normally from a red light and got warning light for the suspension. Immediately, another warning that the front motor was disabled and finally a warning light stating that the 12v battery was low and car could shut off at any point.I left my house with about 200 miles left of charge. I lost almost all power and was trying to get to a safe spot to pull over, but didn't make it. I turned on the hazard lights as one should, but I guess when the 12v goes EVERYTHING goes. the hazards went out within 30 mins. Waited almost 3 hours for a Tesla certified tow truck to come. They tell you to put it into tow mode, but as stated earlier, when 12v goes, NOTHING works. Next step is to open the frunk to access the 12v for a boost. Did I mention...nothing works!!! The frunk was not designed with an emergency latch on the inside of the car, as all other cars ever made. The process is to remove a small plastic cover under the bumper near the right fog light. Once you get that piece open, then you have to fish out two straps and pull on them for the trunk to open. Did I mention I was in the middle of the street for 3 hours? Once we opened the frunk, we had to remove three plastic covers, find the battery and begin to charge it. Luckily, it only took about 3 minutes for us to have enough power to put the car in tow mode. The tesla tech said it could take from 15-30 mins. This whole process took about an hour to get the car fully on the flatbed (assessment,traffic,tow mode and loading on to truck). Rode back with the tow truck and was issued a MS loaner. The SC told me that it was an HD harness that caused all my issues. Waiting for parts and hopefully my car and sanity will come shortly after. Odometer read 96 miles. The car was awesome for the two days I drove it. The SC has been attentive and has promised to do all they can to get me back in my MX as quickly as possible. Aug 5 - ?

jdrand01 | 10 août 2016

Hey guys, that 3 day old MX was mine. I was driving normally from a red light and got warning light for the suspension. Immediately, another warning that the front motor was disabled and finally a warning light stating that the 12v battery was low and car could shut off at any point.I left my house with about 200 miles left of charge. I lost almost all power and was trying to get to a safe spot to pull over, but didn't make it. I turned on the hazard lights as one should, but I guess when the 12v goes EVERYTHING goes. the hazards went out within 30 mins. Waited almost 3 hours for a Tesla certified tow truck to come. They tell you to put it into tow mode, but as stated earlier, when 12v goes, NOTHING works. Next step is to open the frunk to access the 12v for a boost. Did I mention...nothing works!!! The frunk was not designed with an emergency latch on the inside of the car, as all other cars ever made. The process is to remove a small plastic cover under the bumper near the right fog light. Once you get that piece open, then you have to fish out two straps and pull on them for the trunk to open. Did I mention I was in the middle of the street for 3 hours? Once we opened the frunk, we had to remove three plastic covers, find the battery and begin to charge it. Luckily, it only took about 3 minutes for us to have enough power to put the car in tow mode. The tesla tech said it could take from 15-30 mins. This whole process took about an hour to get the car fully on the flatbed (assessment,traffic,tow mode and loading on to truck). Rode back with the tow truck and was issued a MS loaner. The SC told me that it was an HD harness that caused all my issues. Waiting for parts and hopefully my car and sanity will come shortly after. Odometer read 96 miles. The car was awesome for the two days I drove it. The SC has been attentive and has promised to do all they can to get me back in my MX as quickly as possible. Aug 5 - ?

Dcp9142 | 10 août 2016

Thanks, JDRand. A harness defect, not a 12 v battery failure. folks think that the battery just decided to die, but that was a consequence of a manufacturing defect as I understand it.

hami05 | 10 août 2016

@jdrand Wow I'm sorry you had such a major issue in your first week with your new X, and I'm sure that's a very rare thing to happen. Hope you get your car back soon.

rossRallen | 10 août 2016

@jdrand01 - OMG! I'm sorry to hear that you had such a tense and miserable experience. Let's hope the problem is solved quickly and fully.

As for the 12 V battery, I wrote to Elon Musk's office suggesting that the 12V battery voltage and state of charge be displayed on the instrument panel on the same screen as tire pressures. Such a critical system element should not be invisible.

georgehawley.fl.us | 11 août 2016

Good idea @Ross. There are only two possible reasons for the failure of the 12 volt battery: bad 12 volt battery or a problem between the 350 volt battery pack (cabling, connector, fuse, or DC-DC converter circuit). In the latter case the 12 volt battery would not charge off the battery pack and there's should be an immediate warning with enough charge in the 12 volt battery to get to a safe place and put into tow mode. If the latter is not the case, then Tesla has a design problem that needs to be corrected. If the 12 volt battery itself fails, it could be due to gradual degradation. Again a warning about the status of the battery should show up with ample time to get to a safe place if not the service center. If the 12 volt battery has a defect and fails suddenly, there is no recourse.

hami05 | 11 août 2016

@georgehawley What would be really cool is if the Nav rerouted you to a service center when your 12v battery is running low like how it sends you to a supercharger when your range is low. More importantly than that, I do really like Ross's suggestion and hope that's implemented in an update soon.