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12V battery replacement, whos had to do one?

Discussion in 'Model X: Battery & Charging' started by vthreee, Aug 20, 2019.

  1. Need

    Need Active Member

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    Our MX 12v just failed last night. The car won't unlock with either key fobs. The app cannot connected to it. They can't toll it to service because the charger is locked to the port at our garage. Tesla thinks it is a 12v failure and will send out Mobile Tech. We have nothing after market connected to the car and the car is just under 2 years. Drove over 100 miles the day before and no 12v warning. I wonder why the 12v would die suddenly overnight... it was not even cold here.. day time temp over 80.
     
  2. MX2019

    MX2019 New Member

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    It could be the 12V battery or it could be the DC/DC charger (the thing that uses the main battery to charge the 12V battery).
     
  3. MX2019

    MX2019 New Member

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    DC/DC Converter!
    DC/DC Converter!
     
  4. ajdelange

    ajdelange Active Member

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    This is the nature of the modern lead acid battery. They don't, in normal applications, give much if any warning. The Tesla application is not normal and they have pretty sophisticated monitoring designed to give you weeks of warning. Guess that failed here.

    Have you tried jumping it?
     
  5. Need

    Need Active Member

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    No, I don't have a 12V at home. I think you could do it with a 9V battery on M3, but can you do it on the MX? But it really won't do me any good other than I could open the door right? It's not like I could jump it and start driving on it right? We will just wait for the Mobile tech to call to schedule an appointment. It's my wife's car. For now she will just have to Uber.
     
  6. ajdelange

    ajdelange Active Member

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    I'd start by putting a battery charger on it. What this might or might not do I can't say. If the battery has failed it will let you open the doors and perhaps even turn the car on to the point where Tesla can ping it and download logs. If the battery will hold charge you might even be able to drive it. But how far?

    Clearly the lowest risk thing to do is let the ranger handle it. But if you can't get even a ranger there for a week or two (my experience) that's going to be a PITA.
     
  7. Need

    Need Active Member

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    We will see how soon they could get mobile tech to us. And I don't have a battery charger either LOL. I don't work on our cars.. I just call AAA.
     
  8. rreedd

    rreedd Member

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    This is exactly my experience. Woke up to a dead car. None of the fobs work, and it is plugged in. Tesla is scheduling Mobile Tech to come unplug the car, Then schedule a tow. Looks like this might be more prolonged than I initially thought.
     
  9. TonyT

    TonyT Member

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    I don't think 9V would work. The S and X seem to only start up properly when over 13V in my car. under 12.5 and the screens don't even come on. Between about 12.5 - 13 I get a message that says car cant start and shut down, something to that effect. But if I jump start it with another car, voltage goes above 13 and car start right up and can drive for hours. Part of reason I think is so doors and stuff can work. and owners don't get locked out. So it's a pretty good idea to ensure owner can get in car as long as possible.
     
  10. Need

    Need Active Member

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    Okay so Tesla call center person called back saying that he has not heard back from Mobile service and ask if it is okay to toll the car to a service center. So the toll truck came. The driver knew where the manual frunk release is located and popped open the frunk. He had one of those battery jumper. He hooked it up and put the jumper in the frunk and was able to drive the car out to position behind the toll truck. I am thinking when the jumper connected, I could probably drive the car myself to the service center. So my car is now at the service center.

    Now I am wondering if I should get one of those jumper and kept in the frunk!
     
  11. Need

    Need Active Member

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    Oh I was thinking of just popping open the frunk. On the M3, you connect a 12v or 9v battery to the 2 wires and the frunk pops open. I didn't know on the MX that it is just a manual pull on the loops.
     
  12. Need

    Need Active Member

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    The toll truck guy that came yesterday knew how to pop over the frunk, hook up the 12v with his jumper, and unlock the plug. Mobile Tech should be able to just swap out the battery... unless it is not the battery like somehow said above.. could be the DC/DC Converter!
     
  13. TonyT

    TonyT Member

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    I have a Lithium jumper, but for some reason when the car battery was still around 12V the system would not activate... so I could not start the car. If I wait long enough when battery was more low, then the jump pack would activate. I think it is load sensing, and was not drawing enough power to activate. I did measure over 12V with my digital multi meter before and trying to jump... So just a warning some "Smart" jump packs may leave you stuck for a while when your battery is not in the right voltage to activate it.
     
    • Informative x 1
  14. Need

    Need Active Member

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    So the service center replaced my 12v. They said it was swollen physically when they took it out. The log said the car reported battery needs replacing at 5am in the morning. But we didn't use the car all day... at night it was dead. They said the battery still works but the computer detected high resistance during charging so it stopped charging to avoid blowing up the 12V.

    They also said that it is very common on the X but usually around year 3. Ours was just under 2 years. Ours is actually pretty good as the battery is just swollen. They have seen some that started leaking and there would be rotten egg smell.
     
  15. lotorus

    lotorus Member

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    Is the 12V battery definitely covered under the warranty? or an out of pocket expense?
     
  16. Solarman004

    Solarman004 Member

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    I have my 50,000 mile maintenance visit in 2 weeks. Still have the original battery. I think I'm going to have it replaced even if it tests good.
     
  17. Need

    Need Active Member

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    I thought we will have to pay, but our service center didn't charge us. :) They also said that battery on the X seems to go bad faster with lots and lots of short trips. Which is the case for us... my wife work from home and only take short trips.. to take our kid to school and back.
     
  18. ankur1234

    ankur1234 New Member

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    So finally Ordered and installed Ohmmu 12v battery in my 2017 X. It was not as easy as the video shows and took just over an hour. Had to reset the car but worked like a charm. Did drop a wrench and could not get it out. Well it will fall down some day.
     
  19. JamesG

    JamesG Member

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    I have had the 12v battery replaced twice 2016 90D. Both times plenty of warning on the dash message
     

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