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12 Volt Battery Tesla Owners Beware

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Last wkend, while homebound, I noticed a Display note on my '18 Model 3LR - Battery Problem - need a 12 volt battery. This was the first time. Unfortunately, my car did not work - seems you need the 12 volt to get it started. I called West Palm Beach Service center on Monday and they told me they didn't have any 12 Volt batteries NOR could they order one. SERVICE? @elonMusk you need to do better than this. I believe there is a 4 yr warranty on the battery BUT I had to order one from a 3rd Party - Ohmmu.. They were very nice but said they wouldn't be able to guarantee when I will receive it. It was on the way within 36 hr.
Tesla owners beware, - the 2-3 wks of warning on the failing battery seems to be a myth in my case.
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Reactions: vickh
I wonder if the FL heat is a factor (it is for normal 12V). How old exactly and mileage? I agree shame on Tesla for not mobile fixing this unless it's covid related. I might keep AAA just for this

On the good news part Ohmmu is offering covid deals (and they're in AZ BTW).

I'm going to put a meter on the 12V cig light adapter. I think Tesla should allow the HV battery to be a back up at least (a bit like the Roadster)
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Something like this can help you remotely monitor the 12v battery voltage https://smile.amazon.com/dp/B07WCW49YM/

My Model 3 will be 2 years old next month and I'm at almost 40,000 miles. I've had no issues and I have a dual Blackvue dashcam set up to record 24/7. I also never let the car sit for more than 2 days at a time so I think it gets more opportunities to charge. I don't expect to have to replace my 12v battery until the car is out of warranty (10,000 miles and half a year to go) but when I do I will probably get the Ohmmu battery.
Here is my post from a week ago... I never got a warning...

I went out to my car one morning and it was totally dead. I never got a warning on my screen mentioning a low battery condition. I figured I could hook up my portable battery jumper and drive to the service center for a replacement battery. I couldnt even get the tow hook cover off. It wouldnt budge at all. I left the car alone for a few hours and was lucky enough to pop open the frunk by the app. I connected the portable jumper to the battery hoping to get enough to start the car and drive but it never worked. Tesla sent a tow truck but it was unable to pull my car out of my garage because the car would not go into tow mode. Tesla sent a second tow truck with a special remote controlled device that was able to pick up my car while it was in my garage. It was totally cool to watch because I've never seen one of those before, however I think it would have been a lot more cost effective to send out a mobile tech with a battery. My car was delivered to the service center around 9pm and i got a call that it was ready for pick around 8am the following day. It was really fast service and they paid for me to take a Uber ride to the service center. I was really happy with the service. The worrying part is that the tech told me that I should have been getting warning message on the screen about a week before the battery died. The battery only lasted about 15 months down here in Miami. I think I'll have to put it my calendar for 15 months from now to maybe have them run a test on it. I wish there was some way to see the condition of the 12v battery somewhere on the screen (like a battery meter).

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If I recall correctly I think Elon tweeted that a battery condition monitor for the 12V battery would be forthcoming in a future FW upgrade.

That’s what I heard also. This functionality is on the way.

I’ve owned many different vehicles, and when the batteries died in those, I had no warning either.
In fact, when it did, it was always the dealerships opportunity to replace the alternator first, only to then tell you, it’s the battery after all, and bill for both. ...
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Reactions: Electric Steve
First, why would you accept the answer that they couldn't order one? It's under warranty, tell them to fix it.

Second, did you try to jump start the car? This is the same as jump starting an ICE and is documented in the manual.

Third, the reason Tesla still has a 12V in the car is because it's mandated for safety regulations. Those regulations have not caught up, but Tesla did improve the 3 to have the HV battery monitor and keep the 12V charged. This is to avoid the problem that plagued the S (and maybe the X).