[ctaylor2047]

Seems like since one can get stranded with a failed 12 volt battery there should be a better warning of the impending failure.
I suggest the warning should be an audible that requires driver to acknowledge it, Additionally the warning should be made when starting to drive off and when finishing the drive. I asked my friend that had to replace his, he said his wife missed the alert. Hmmmppfff, maybe the alert should go to the husband's phone as well.

 

[Ed Woodrick]

My car was showing a warning when I drove it. It occurred well in advance of any failure. Lots of Model 3 owners have been receiving the warning over the past year. Model Ys aren't quite old enough yet.

The notification was quite obvious and the driver had to explicitly ignore it

 

[MYLR2023]

12 volt batteries tend to fail > 4yrs or so. My ICE is 8 years old and on 3rd battery. A bit less than > 4yrs. With my 2023 Y I plan on having it replaced at 4yrs to be on the safe side and not to trust perhaps there will be a warning in time.

 

[JasonF]

There is an alert, but batteries fail in so many different ways, it doesn't catch all of them.

For instance, the new lithium based 12 volt batteries tend to be healthy one day, and completely dead the next. And the lead-acid ones sometimes degrade slowly, other times go "dead cell" one day, and sometimes there is no indication anything is wrong with a lead-acid until one day it stops taking any charge whatsoever.

 

[Rub"Y"]

12 volt batteries tend to fail > 4yrs or so. My ICE is 8 years old and on 3rd battery. A bit less than > 4yrs. With my 2023 Y I plan on having it replaced at 4yrs to be on the safe side and not to trust perhaps there will be a warning in time.

81

Your 2023 Y has a 15 volt lithium ion battery, these may last as long as the high voltage battery.

"13"

 

[MYLR2023]

For instance, the new lithium based 12 volt batteries tend to be healthy one day,

in my ice vehicle my battery completely failed 3 days after being tested at it's regular maint appointment.

 

[MYLR2023]

these may last as long as the high voltage battery.

....maybe, maybe not. After coming out to my RDX twice with a totally dead battery and both times needing to go to work I'm not taking chances. Seen posts here and there about the Tesla 12v biting the big one, so I prefer to be prepared vs being stung (so to speak). That's year out from today, so not worried at all....hopefully.

 

[Rub"Y"]

My wife's TLX had a bad battery after the first year, replaced and no problem since. Didn't bother with dealer, they are the worse ever. But like I said our model Y has a different battery not Lead acid.

 

[MYLR2023]

they are the worse ever.

first battery that failed around 4yrs I had Acura dealer switch 'em. Second battery at just 3 years I had AAA change it. Live and learn. No doubt years from now I'll check on what Tesla 'recommends' as I don't trust battery testers for shyte. Reading posts beyond here they do, at times, tend to fail unexpectedly, so I prefer to hedge my bets vs waiting.

 

[Electrocat]

Seems like since one can get stranded with a failed 12 volt battery there should be a better warning of the impending failure.
I suggest the warning should be an audible that requires driver to acknowledge it, Additionally the warning should be made when starting to drive off and when finishing the drive. I asked my friend that had to replace his, he said his wife missed the alert. Hmmmppfff, maybe the alert should go to the husband's phone as well.

ICE car 12V battery warning, no crank happens.

 

[MYLR2023]

ICE car 12V battery warning, no crank happens.

or every single LED lights up on the dash with perhaps a 'click'. One just needs to know that is the battery.......

 

[Gordon87]

I have a M3, build 12/2018. Based on this or another post, I scheduled a mobile service call which I had this morning, to check the battery. Here is what the mobile tech said:

1. They don't bring a battery load tester. However, every time the car starts (when you first put your foot on the brake), it runs a diagnostic and will alert you on the Tesla screen if the battery has an issue. He indicated that you can't miss it. However, since this is only done when the car is about to be driven, it won't show up on the Tesla app.

2. With the old 12v lead acid batteries, it doesn't mean the battery will immediately fail and some people have driven up to a month with it with no problem, but you should use the car's notice as a reminder to get the battery checked and replaced. Part of this may be because the lead acid batteries are more powerful than the newer lithium ion batteries, but the newer lithium ion batteries may last longer. So, if you have the newer lithium ion battery, maybe make sure to get it checked when the car tells you there is a problem with the battery.

3. When a software update is available to be installed, the car will also automatically run the diagnostic to check the 12v battery as it needs that battery for the update, where the main battery will not be available. If based on that diagnostic, the 12v battery has a problem, it will notify you on the Tesla screen and will not install the update. However, he did not know whether this issue will also show up on the Tesla app. I am hoping that it would, since if the battery is ok, the Tesla app will show the update ready to be installed.

 

[311Hokie]

FWIW - much like others have said. Took delivery of my M3 in May of 2018.

Got notification that "low voltage battery in need of replacement" in Jan of this year.

Scheduled service for following week on the Tesla app and had it replaced for just over $100 in about 30 min at the service center.

Incredibly easy and painless process.

 

[Andy96734]

‘16 MX and got the warning but in 2 of the 3 times it died within a day or two—third time on morning of scheduled service call made the day before when the warning came on. So post warranty cost is now mine so switched to 12V LFP Batteries for Tesla and EVs | Ohmmu | United States and no more battery every other year wonder when it will happen change outs. The reliability and capability are worth the extra upfront cost, and greener too.

 

[JasonF]

1. They don't bring a battery load tester.

That's because those aren't terribly useful. The maximum load a Tesla (or any EV) draws from the 12V battery is when it's starting up the MCU. The contactors wont draw much when they close, and the coolant pump doesn't really draw that much (the steering motor does, but that's only active while the main battery is engaged).

2. With the old 12v lead acid batteries, it doesn't mean the battery will immediately fail and some people have driven up to a month with it with no problem, but you should use the car's notice as a reminder to get the battery checked and replaced. Part of this may be because the lead acid batteries are more powerful than the newer lithium ion batteries, but the newer lithium ion batteries may last longer. So, if you have the newer lithium ion battery, maybe make sure to get it checked when the car tells you there is a problem with the battery.

The lithium ion batteries are probably able to draw more amps than a lead-acid battery, but the danger is that they tend to fail very suddenly. By the time it fails one test, it may be dead seconds later.

Also interesting to note, there are two separate battery warnings that I know of. The orange "12 volt battery needs service" just means when you get around to it. There's another one that's red and says something about there not being enough power to run all of the accessories - and that one is basically your last warning. Right after that is "Vehicle will not charge"/"Vehicle May Not Restart" and the real imminent danger one, "Vehicle May Shut Down Unexpectedly".

That last one is the one I got, and the reason why the Service Center rushed my 12 volt battery replacement. Because I understood how the car works though, I didn't have it towed - I left the HVAC running to prevent the contactors from opening, and made 2 stops on the way to the SC.

 

[barbsimoesvt]

Seems like since one can get stranded with a failed 12 volt battery there should be a better warning of the impending failure.
I suggest the warning should be an audible that requires driver to acknowledge it, Additionally the warning should be made when starting to drive off and when finishing the drive. I asked my friend that had to replace his, he said his wife missed the alert. Hmmmppfff, maybe the alert should go to the husband's phone as well.

You should have said "spouse" or "partner". Women are often more reliable than men...just sayin'.

 

[Tesla Mark]

If your 12v dies it can be jumped, kind of like the old days, but you need to know how to open your frunk with no 12v battery power and that the car jumping yours should NOT be running.
Of course, none of this applies if you have one of the new lithium 15v batteries (2021+ models). Good news is that these batteries should last a lot longer than the 12v's.
More on all of this and how to get into your frunk here.