Model S

12 v battery needs service.

edited November -1 in Model S
How long can I continue driving the car with a 12 v battery needs service warning. I cannot get the battery serviced for 3-4 weeks due to travel plans.


  • edited November -1
    Are these travel plans via the car? Stop by a service center where it is you are going to get a new battery.
  • edited January 2020
    @paul - Generally it seems most owners are able to go up to 3 weeks without any problems. Not much data on waiting longer, so I'd start to get uncomfortable going a full month. It might be fine, but it might not. Then it would require a tow.
  • edited January 2020
    Mine sat at 7v for weeks, with HV at 0 miles. I charged it and it was fine. Then it sat at shop a week where they left it connected and it was toast.

    If it goes dead when the HV is low, you cannot charge. Then I would not drive it, disconnect 12v battery, and HV quick disconnect next to battery. That will buy some time.
  • edited January 2020
    On a side note, you can disconnect both, then put a good charger on the 12v and it will likely last for months more. A good charge from a real charger seemed to help mine alot and got rid of error messages. An automatic AGM charger with 20 amp capabilities is ideal. I like to get them brought up on 20a and then trickle at low amps for a long time.
  • edited January 2020
    I had a similar issue a couple months back. My appointment was for 3 weeks away. I called and said I drive about 150 miles a day. There is no way I can be broke down 60 miles from home. The next day my appointment was switched to the next day, hey came and changed the battery at my job. This is not under warranty though cost me $200
  • irir
    edited January 2020
    When I got the alert, the earliest appointment was 1 week later. The day before the appointment, Tesla cancelled due to lack of parts. Apparently they don’t check for parts availability until the day before.

    Got assurances the car would be fine until they sourced parts and rebooked the appointment.

    I started smelling a strong sulfur smell in my garage and home. Evacuated and called gas company. Turned out the 12v was making the smell when charging from the 400v battery. Had to park car outside. The battery failed shortly after and needed to be towed.

    Be careful if the battery starts emitting sulfurous gases!
  • edited January 2020
    Ir- I’ve seen this reported a lot, that smell! Others have done just what you did and called the gas company.

    My guess is that someone else drove to Telsa with the same problem (instead of waiting for their appointment) and got your battery!

    FWIW - I plan on getting an Ohmmu battery as soon as that warning pops up. That biz is in Phoenix so I can (hopefully) drive down and meet Sean to get one. I’m happy to pay 2x the price if it lasts at least 2x as long and weighs less in the process with no lead.
  • edited January 2020
    Just saw 12v needs service, after starting local hpwc charge. After completed charge to 80%, couldn’t get summons to flash on off headlights by holding fob button. Can lock and unlock doors, and open door. But don’t get headlight visual summons activated state; waiting for direction press.

    Moved other car out of garage to see if MS85 would engage drive, which it did.

    Is not having summons common with 12v needs service error?

    Use summons many times a day. Thx
  • edited January 2020
    @Bill_75D - Not sure it relates. The quick take to me is the owner installs a non-standard 12v battery and breaks some wires or bracket and expects Tesla to fix it under warranty. Maybe I missed something and perhaps could have been handled better by both sides.

    Now I've installed all sorts of stuff in my car, and if I break something, I fix it or have them fix it out of warranty. None of my additions have affected the warranty on unaffected areas.
  • edited January 2020

    "Now I've installed all sorts of stuff in my car, and if I break something, I fix it or have them fix it out of warranty. None of my additions have affected the warranty on unaffected areas."

    That's because there is a federal law that requires that.
  • edited January 2020
    @murphy, I was aware of that but good to point it out to others. In my experience, Tesla has been good about non-Tesla modifications - at least within reason.
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