Master thread: Model 3 12v Battery issues, monitoring, Aftermarket replacement

[rrolsbe]

if you are plugged into the Tesla provided 12V outlet located under the center console lid, I can't imagine that hurting anything. Unless something has changed, the 12V power is only available when the PCS is operational which provides the power. When the car enters sleep mode no power is available to the center console outlet. The PCS can deliver somewhere around 200A, so the Dashcam power draw would be in the noise. Now if you are using a 12V outlet you or someone else installed that could be a different issue. If your Dashcam is drawing 12V power while the car is sleeping, you are adding at least slightly more charge/discharge cycles to the 12V battery. I you are using the center console outlet, I would remove the Dashcam before Tesla arrives to repair any car issue.

 

[rrolsbe]

I want to qualify my slightly more charge/discharge comment in my last post. It is my understanding the power draw on a typical Model 3 while sleeping is around 7W; therefore, if you had a dual DashCam setup that was using power during the car's sleep state, you could be pulling several watts. If that power draw is near 7W, you are potentially doubling the number of allowed lifetime charge/discharge cycles on the 12V battery. I am not familiar with power usage of the different Dashcams sold maybe someone more knowledgeable can weigh in? So this might be why Tesla makes the blanket statement to the Ranger/repair personnel , Dashcams are bad? Now the same thing could apply to ICE vehicles. Do ICE vehicle manufacturers have the same exception regarding their 12V battery warranty?

 

[cyberjoe]

I know there are other threads about this 12V battery problem. But I got some good insights into this issue.

First my story.

Model 3 stealth performance is 8/2018 model - one of the first off the production line. Love the car.

About 4 days ago, I got the 12V battery issue warning. IMMEDIATELY i scheduled a service appt via the app

There were ZERO appointments within 2 weeks. So I scheduled it at the earliest time slot available. (This is the SF bay area so service department is likely busier than most locations)

I thought about calling tesla about this to get an earlier appointment but got busy with life. Also, I was curious how long the 12V battery would last after the warning and if Tesla has a good system to fix it.

Conclusion: 12 V battery lasted 4 days after warning. Thankfully died at home in my garage.
Tesla does not prioritize or recognize this 12V battery replacement as an urgent priority in terms of appointments (this can be fixed with just software)
My model 3 is about 2.5 years old and 36,000 miles.


I spoke with the towing guy who had to tow away my car to the service center after jumpstarting the car. Once the 12V battery dies, the doors cannot be opened from the outside, trunk cannot be opened, and even the charging port cannot be unhooked if you are plugged into charge.

Towing guy said, he's seen increasing model 3, 12V battery failures and rare cases of even 2020 models have this issue. Only seen one model Y with this issue (Which means little since so few model Y on the road currently).

So as soon as you see the warning, I would CALL tesla and demand a service appointment within 1-2 days MAX. 12V battery failure can be dangerous especially in the winter if you cannot even get back inside your car!!!

Anyone at Tesla seeing this. Tens of thousands of model 3 will need 12V battery replaced- let's not wait to have some angry tesla owner or someone's life put into danger.

As a tesla shareholder, I'm going to call the customer service make sure they are aware this is a HUGE service issue.

 

[sightman]

Why does this require a service appointment as opposed to getting a battery at the auto parts store. Am I missing something?

 

[RandyS]

Why does this require a service appointment as opposed to getting a battery at the auto parts store. Am I missing something?

The exact OEM replacement is not available at most auto parts stores...Sometimes the car's software has to be tweaked by the tech as well (assuming they change battery or charging parameters)...

 

[tstolze]

Why does this require a service appointment as opposed to getting a battery at the auto parts store. Am I missing something?

Not sure what the warranty is on the 12v battery, but I would think being under 3 years it would be covered.

 

[KenC]

A 51R should fit. About $100 at my Sam's Club, (pictured below). Probably a touch more at Walmart. I don't see why using one as a bridge unit, until Tesla got around to putting in one of their $85 batteries. Seems like cheap insurance to me, much preferable to getting stuck somewhere, and having to call for a tow.

Before doing the above, please read up how to do it, since it requires disconnecting the HV battery.

As for Cyberjoe's experience, I would consider a failing 12V a safety issue, that should get priority from Tesla. I can't see how it's less expensive for them to have to pay for towing, when a 12V fails on the road. Sometimes Tesla needs to be more proactive. It's like Elon's blindspot. Safety has to be priority #1. It's bad optics for the company not to take this more seriously.

 

[DonTom]

I only have 5,427 miles on my 2018 Tesla M3, LW, AWD purchased new in Oct 2018. I have a few questions about the 12 volt battery. I still am using the original.

I recall there are a couple of wires below the right side of the left headlight (driver's side) under that round cap. I know those are to activate the doors and such if the 12 V batteries dies. I think I heard somewhere that all it takes is a little 9 volt battery to activate so the doors can be opened--and I assume drive with a dead 12 volt battery as then the DC2DC converter will supply the voltage from then on, while driving. I am surprised to hear the DC2DC converter is not activated also while charging.

Is it really possible to use a small 9V battery there? If so, I guess I should keep one in my pocket!

Another question is it worth it to install the Lithium 12 volt battery for $479.00?

And does the warning usually come on before the battery dies? I had no idea there was such a warning until I read this thread.

So when I am I mostly likely to need to replace this battery?

-Don- Reno, NV

 

[M3BlueGeorgia]

I only have 5,427 miles on my 2018 Tesla M3, LW, AWD purchased new in Oct 2018. I have a few questions about the 12 volt battery. I still am using the original.

I recall there are a couple of wires below the right side of the left headlight (driver's side) under that round cap. I know those are to activate the doors and such if the 12 V batteries dies. I think I heard somewhere that all it takes is a little 9 volt battery to activate so the doors can be opened--and I assume drive with a dead 12 volt battery as then the DC2DC converter will supply the voltage from then on, while driving. I am surprised to hear the DC2DC converter is not activated also while charging.

Is it really possible to use a small 9V battery there? If so, I guess I should keep one in my pocket!

Another question is it worth it to install the Lithium 12 volt battery for $479.00?

And does the warning usually come on before the battery dies? I had no idea there was such a warning until I read this thread.

So when I am I mostly likely to need to replace this battery?

-Don- Reno, NV

Yes, no, no, yes.

And when you get the warning, don't dally. Make an immediate appointment with Tesla through the application to get it replaced.

 

[KenC]

I only have 5,427 miles on my 2018 Tesla M3, LW, AWD purchased new in Oct 2018. I have a few questions about the 12 volt battery. I still am using the original.

I recall there are a couple of wires below the right side of the left headlight (driver's side) under that round cap. I know those are to activate the doors and such if the 12 V batteries dies. I think I heard somewhere that all it takes is a little 9 volt battery to activate so the doors can be opened--and I assume drive with a dead 12 volt battery as then the DC2DC converter will supply the voltage from then on, while driving. I am surprised to hear the DC2DC converter is not activated also while charging.

Is it really possible to use a small 9V battery there? If so, I guess I should keep one in my pocket!

Another question is it worth it to install the Lithium 12 volt battery for $479.00?

And does the warning usually come on before the battery dies? I had no idea there was such a warning until I read this thread.

So when I am I mostly likely to need to replace this battery?

-Don- Reno, NV

Mine is also a Oct 2018 build. I carry a 9volt battery in all my coats. I don't think it opens the doors, but opens the frunk, so you can access the 12V. When will you need a new battery? Of course when you least expect it.

 

[Brock-WI]

Is it true I can just buy a "spare" or replacement 12v battery from a tesla service center? I looked at the battery swapping procedure and can do that no problem. Our closest service center is 120 miles from here but we are occasionally near there and would like to just get one as a spare, especially if the replacement from Tesla is less than the $120 for the 51R from Walmart.

 

[M3BlueGeorgia]

Is it true I can just buy a "spare" or replacement 12v battery from a tesla service center? I looked at the battery swapping procedure and can do that no problem. Our closest service center is 120 miles from here but we are occasionally near there and would like to just get one as a spare, especially if the replacement from Tesla is less than the $120 for the 51R from Walmart.

Its definitely something routinely done through Mobile Service, so being 120 miles from a Service Center shouldn't be a major concern.

 

[rrolsbe]

I only have 5,427 miles on my 2018 Tesla M3, LW, AWD purchased new in Oct 2018. I have a few questions about the 12 volt battery. I still am using the original.

The following comments are correct AFAIK. Since you have low mileage on your 2+ year old car, the 12V battery has probably seen many more charge cycles than the norm; therefore, there is a chance it might be nearing the end of it's useful life.

I recall there are a couple of wires below the right side of the left headlight (driver's side) under that round cap. I know those are to activate the doors and such if the 12 V batteries dies. I think I heard somewhere that all it takes is a little 9 volt battery to activate so the doors can be opened--and I assume drive with a dead 12 volt battery as then the DC2DC converter will supply the voltage from then on, while driving. I am surprised to hear the DC2DC converter is not activated also while charging.

The wires behind the tow hook cover only open the frunk to give access to the 12V battery area. Tesla made a firmware change several months back that disallows opening the frunk,, via the tow hook wires, when the 12V battery is functional.

Anytime the car is awake the DC-to-DC converter is operational. In fact, you can disconnect the 12V negative cable anytime the car is in the awake state and everything works fine (you will get a message on screen that the 12V battery is disconnected). The 12V battery is required to close the HV contactors to transition from the sleep to operational awake state.

Is it really possible to use a small 9V battery there? If so, I guess I should keep one in my pocket!

Yes, last time i tried it. Maybe someone else who has tried it recently can confirm?

Another question is it worth it to install the Lithium 12 volt battery for $479.00?

And does the warning usually come on before the battery dies? I had no idea there was such a warning until I read this thread.

So when I am I mostly likely to need to replace this battery?

-Don- Reno, NV

 

[rrolsbe]

Its definitely something routinely done through Mobile Service, so being 120 miles from a Service Center shouldn't be a major concern.

Your absolutely correct about the Rangers replacing the 12V batteries. Since the cost is about the same, I might purchase a spare AGM battery from Tesla in lieu of a Jumpstarter battery. I would keep this battery in the frunk along with a 10MM wrench to allow change out and a 9V battery in my pocket. If I am stranded due to a 12V battery failure, I would much rather install the spare battery and get on down the road in 10 minutes. I can deal with Tesla regarding the failed battery later. If Tesla declined to cover the failed 12V battery under warranty so be it. Even though the 12V battery should be warranted for 4 years or 50K miles, the hassle factor of waiting for roadside assistance would probably not be worth it (unless I am parked in my garage and do not need to go anywhere). When I go hiking in the mountains I almost never have Cellphone service, so calling for Roadside service would be a problem; likewise, even if road side assistance would come to a mountain trailhead, how long might that take.

 

[Brock-WI]

Your absolutely correct about the Rangers replacing the 12V batteries. Since the cost is about the same, I might purchase a spare AGM battery from Tesla in lieu of a Jumpstarter battery. I would keep this battery in the frunk along with a 10MM wrench to allow change out and a 9V battery in my pocket. If I am stranded due to a 12V battery failure, I would much rather install the spare battery and get on down the road in 10 minutes. I can deal with Tesla regarding the failed battery later. If Tesla declined to cover the failed 12V battery under warranty so be it. Even though the 12V battery should be warranted for 4 years or 50K miles, the hassle factor of waiting for roadside assistance would probably not be worth it (unless I am parked in my garage and do not need to go anywhere). When I go hiking in the mountains I almost never have Cellphone service, so calling for Roadside service would be a problem; likewise, even if road side assistance would come to a mountain trailhead, how long might that take.

My thoughts exactly. I can change it myself easily enough and if it happened during a snowstorm while out shopping, that wouldn't be fun. Also waiting on the time for a ranger to come and replace even if the car happened to be at home seems silly. I wouldn't want them to waste 5 hours of their day when they could be helping someone who needs something now when I can change it myself.

Heck I might just get one and swap it right away for piece of mind. Now to see if I can just pick one up of if I have to order it or?

 

[DonTom]

And when you get the warning, don't dally. Make an immediate appointment with Tesla through the application to get it replaced.

I plan on replacing it myself. A lot less hassle. I usually fix my own problems even during the warranty period at my own cost, when possible.

Replacing the 12 volt battery is a very simple job:

 

[DonTom]

Mine is also a Oct 2018 build. I carry a 9volt battery in all my coats. I don't think it opens the doors, but opens the frunk, so you can access the 12V. When will you need a new battery? Of course when you least expect it.

In that case, I will carry the 9V battery AND keep a new spare 12V battery in the Frunk. Just for the fact that the lithium should have a very long shelf life and is lighter and can be stored in any position, that makes it good idea to keep in the frunk if I do not want to replace it before the stock battery craps out.

-Don- Reno

 

[KenC]

In that case, I will carry the 9V battery AND keep a new spare 12V battery in the Frunk. Just for the fact that the lithium should have a very long shelf life and is lighter and can be stored in any position, that makes it good idea to keep in the frunk if I do not want to replace it before the stock battery craps out.
-Don- Reno

Sounds like a plan. I keep a Noco lithium starter in the frunk. The car doesn't need much from the 12V, so I hope the Noco will have just enough power to get the car going, if the 12V fails somewhere. Then I can run over to Sams or Walmart to get a 51R to replace it, after checking with Tesla and finding out how long it will take to get a warranty replacement via mobile ranger.

 

[DonTom]

Sounds like a plan. I keep a Noco lithium starter in the frunk. The car doesn't need much from the 12V, so I hope the Noco will have just enough power to get the car going, if the 12V fails somewhere. Then I can run over to Sams or Walmart to get a 51R to replace it, after checking with Tesla and finding out how long it will take to get a warranty replacement via mobile ranger.

Is the 12V required to drive the car if you can get in it?

-Don- Reno, NV

 

[cyberjoe]

I only have 5,427 miles on my 2018 Tesla M3, LW, AWD purchased new in Oct 2018. I have a few questions about the 12 volt battery. I still am using the original.

I recall there are a couple of wires below the right side of the left headlight (driver's side) under that round cap. I know those are to activate the doors and such if the 12 V batteries dies. I think I heard somewhere that all it takes is a little 9 volt battery to activate so the doors can be opened--and I assume drive with a dead 12 volt battery as then the DC2DC converter will supply the voltage from then on, while driving. I am surprised to hear the DC2DC converter is not activated also while charging.

Is it really possible to use a small 9V battery there? If so, I guess I should keep one in my pocket!

Another question is it worth it to install the Lithium 12 volt battery for $479.00?

And does the warning usually come on before the battery dies? I had no idea there was such a warning until I read this thread.

So when I am I mostly likely to need to replace this battery?

-Don- Reno, NV

the warning came and the car lasted only about 4-5 days. But I would literally get on it within 48hrs TOPS. The car is like a dead brick when the battery goes. you cannot even open the door!

This is why I'm worried as a tesla investor EVEN more than as a driver. Huge safety issue and PR issue. Thousands of people will start having this issue in the coming months as 2019 model 3 will start getting dead batteries - how many were sold in 2019 - A TON of model 3s!