12 volt may or may not die before I can get it replaced🤷‍♂️

[Mesogreat]

Woke up to the screen saying my 12v is dying. Hell of a coincidence this happened the day I got fsd. Now it’s looking like I can’t get a mobile appointment until Thursday. Do we think my battery going to die before my appointment . If so what’s the procedure after my car turns in to a giant paper weight. The tesla service center has been pretty cold and heartless about the whole thing. I’m kind of freaking out as my car is needed for my work. Lives are actually involved with the sudden disappearance of a vehicle. I’m just trying to work out the what if’s.

 

[davewill]

It's not a terribly difficult DIY project if you're mechanically inclined at all. Here's a how to video:

 

[archae86]

They don't usually fail all that fast. I think you probably have a few weeks before it is even a worry.

 

[Mesogreat]

It's not a terribly difficult DIY project if you're mechanically inclined at all. Here's a how to video:

They don't usually fail all that fast. I think you probably have a few weeks before it is even a worry.

This is what I was hoping someone would say. I’m going to cross my fingers that all will go well up to my Thursday mobile appointment. Thank you for your reply

 

[danarcha]

This is what I was hoping someone would say. I’m going to cross my fingers that all will go well up to my Thursday mobile appointment. Thank you for your reply

I would recommend turning on sentry mode and leaving it on all the time. That prevents your car from going asleep. If the 12V completely fails, it won't wake the car up and it will be undriveable, but if the car stays awake it should be fine to drive. There are some reports that recent software updates force the car to stay awake whenever 12V error occurs, but turning on sentry mode is a way to force the car to stay awake.

 

[Mesogreat]

I would recommend turning on sentry mode and leaving it on all the time. That prevents your car from going asleep. If the 12V completely fails, it won't wake the car up and it will be undriveable, but if the car stays awake it should be fine to drive. There are some reports that recent software updates force the car to stay awake whenever 12V error occurs, but turning on sentry mode is a way to force the car to stay awake.

Just turned it on! Thank you for the advice again.

 

[jjrandorin]

They don't usually fail all that fast. I think you probably have a few weeks before it is even a worry.

This isnt true for Model 3s, at least ones from 2017-2022 (until they changed them to factory Lithium Ion batteries. Many (many many) people had them fail with no notice, and for ones that did get a notice, they usually fail shortly after, measured in a few days tops. I could point you to a number of threads but if you search here for "12v battery" you will see most of them.

 

[Mesogreat]

That’s concerningmines a 2019

 

[STS-134]

This isnt true for Model 3s, at least ones from 2017-2022 (until they changed them to factory Lithium Ion batteries. Many (many many) people had them fail with no notice, and for ones that did get a notice, they usually fail shortly after, measured in a few days tops. I could point you to a number of threads but if you search here for "12v battery" you will see most of them.

When did these incidents occur though? There was probably a software bug in the notification system, which has since been fixed, although I wouldn't rule out Tesla reintroducing the bug and screwing over a new group of people before they figure out something's wrong and fix it again, so it's best to test the battery regularly. It's not going to go from good to completely failed in a month or even two months.

 

[jjrandorin]

When did these incidents occur though? There was probably a software bug in the notification system, which has since been fixed, although I wouldn't rule out Tesla reintroducing the bug and screwing over a new group of people before they figure out something's wrong and fix it again, so it's best to test the battery regularly. It's not going to go from good to completely failed in a month or even two months.

I was just commenting on "its usually a few weeks after the notice until its a worry" which has not been the reported case here.

one such thread:

How urgent is "12V battery degraded" warning?

Today my wife's Model 3 displayed a dialog saying the 12V battery has degraded and should be serviced. The car is 3 years old, so I know it's not unusual to have to replace the battery at this point, but I was wondering how urgent the replacement is. There have been no symptoms of 12V battery...

teslamotorsclub.com

Dec 4th 2021

Dec 5th 2021 (a day later)

I have not seen a single thread here on TMC the entire time I have been here, in the model 3 subforum, where someone says " I got the 12v battery warning and waited weeks before I got it replaced, and the battery lasted all that time".

I have seen people do what @danarcha recommended, which is keep the car awake somehow, either sentry mode or something else that keeps it awake.


I was commenting on the comment made that this OP "had weeks" which has not been the reported case. They will be lucky to get "days" unless they keep the car perpetually awake.

 

[RoBoRaT]

@Mesogreat

I would also prep for tow via flat bed in case the 12V died by: Pointing the car where you don't need to reverse out of the location; roll down the driver side window; open the frunk - assuming your car is inside a secure place.

I am curious about the state of the 12V battery - test it somehow. I know you can see the state in the Li-ion Low Voltage (16V) battery of newer Tesla Models by going to the in-car Service Mode.

Does yours show 12V battery state in Service Mode?

 

[P3dStealth]

@Mesogreat

I would also prep for tow via flat bed in case the 12V died by: Pointing the car where you don't need to reverse out of the location; roll down the driver side window; open the frunk - assuming your car is inside a secure place.

I am curious about the state of the 12V battery - test it somehow. I know you can see the state in the Li-ion Low Voltage (16V) battery of newer Tesla Models by going to the in-car Service Mode.

Does yours show 12V battery state in Service Mode?

The lead acid 12v batteries don't show a status in service mode. The battery tab actually looks a lot different than yours.

 

[Mesogreat]

I

@Mesogreat

I would also prep for tow via flat bed in case the 12V died by: Pointing the car where you don't need to reverse out of the location; roll down the driver side window; open the frunk - assuming your car is inside a secure place.

I am curious about the state of the 12V battery - test it somehow. I know you can see the state in the Li-ion Low Voltage (16V) battery of newer Tesla Models by going to the in-car Service Mode.

Does yours show 12V battery state in Service Mode?

Thats a good question I’ll check tomorrow . I’ll definitely prepare the car for a just in case of a tow situation. With my night work I could have the car in all kinds of parking situations. I’ll think about that now. Oh and How do I not have the Windows automatically roll up?

 

[AlanSubie4Life]

I would recommend turning on sentry mode and leaving it on all the time. That prevents your car from going asleep. If the 12V completely fails, it won't wake the car up and it will be undriveable, but if the car stays awake it should be fine to drive.

The "12V dying" warning message on the screen also says standby power will be high (there are two or three messages that quickly cycle by when the detection occurs). This is because Tesla forces the car to idle mode all the time when the battery is detected as defective. That means that the 12V is no longer needed (in theory the OP could disconnect it, though I certainly don't recommend that, no need to tempt fate).

So turning Sentry Mode on all the time (if the notification has come on) should not be necessary. Of course, Tesla could always have screwed up the software and adding the Sentry Mode protection layer to prevent sleeping could help.

But it's definitely a good idea to turn on Sentry Mode if you suspect your 12V might be weak (but with no warning), you're going somewhere really cold with that weak battery, etc. Just as long as you account for the high drain (though if your car detects the 12V as bad you're going to be stuck with that drain anyway, at least you can be sure that your car does stay awake with Sentry Mode).

But it should not be necessary as long as the car has detected the battery as bad, and Tesla's software is working correctly (last phrase is doing a lot of work).

 

[RoBoRaT]

The lead acid 12v batteries don't show a status in service mode. The battery tab actually looks a lot different than yours.

View attachment 878394

Got it - no page for 12V Battery.

 

[RoBoRaT]

I

Thats a good question I’ll check tomorrow . I’ll definitely prepare the car for a just in case of a tow situation. With my night work I could have the car in all kinds of parking situations. I’ll think about that now. Oh and How do I not have the Windows automatically roll up?

You can disable "Automatically Roll up Windows on Lock"

 

[Mesogreat]

You can disable "Automatically Roll up Windows on Lock"

Ahh ok. Thanks

 

[P3dStealth]

If the only reason you are waiting is for mobile service to stop by...

You could just drive to Tesla and buy the battery. It's only $85. It would probably take you 10mins to swap the 12v even if you were reading the service manual and never used a ratchet before. It's very easy and accessible. It's very small and has a handle so it's even easy to lift out. You will also save whatever it is they charge for mobile service. Just an option but some people are just not comfortable working on things so it's understandable if you don't want to.

 

[archae86]

Well--if there are no reports of waiting a good while before failure here, it is probably because those people did not think it worth starting a thread to post about it. My own single hearsay sample is that of a pretty early S owner (he got his second S shortly after dual-motor was offered, and that was the one). His car told him he needed a new battery. Service told him they were out of stock, so it would be a few weeks. He was not happy, but they reassured him all would be well, and so it was.

So, now can we say the sample size on the other side of the ledger is one, not zero?

But my comment was not based solely on his experience, but also on my understanding of the usual deterioration curve of lead-acid batteries, and my presumption that Tesla's detection scheme was not wholly deficient. I'll learn from this episode, if it is reported here.

 

[STS-134]

@Mesogreat
I am curious about the state of the 12V battery - test it somehow. I know you can see the state in the Li-ion Low Voltage (16V) battery of newer Tesla Models by going to the in-car Service Mode.

Completely useless. SoC is not SoH.