Model S

12 Volt Battery replacement

edited March 2018 in Model S
So my Model S P100D is giving me an error message "12V Battery Needs Service - Replace 12V Battery Soon". Its winter here in the mid-Atlantic, but the car sits in a garage and is plugged into a wall charger when its not being driven. I called the local Tesla sales/service and scheduled a replacement. They called the morning of the replacement and cancelled the appointment, because they did not have any 12V batteries for a Model S. I am really worried about Tesla, this is poor service and its poor design. I have other vehicles that can sit for months without being plugged in and start right up from their 12V. I have farm equipment that can stay on a trickle charge all winter and start right up. You would think a company that prides itself in electric vehicles and power management would be able to do better than this for a vehicle that has been plugged in and is less than a year old.
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Comments

  • edited November -1
    Don't worry about it. Just get it replaced in the next month or so.
  • edited March 2018
    I totally freaked out about this when it happened to me. Then I drove to France. And back again. Then got it replaced.

    @tes-s is right. Don't panic about it.
  • edited November -1
    That message appears 2-3 weeks before failure and if you called customer support that's the exact bit of information given to you. Calm down, you'll be fine.

    By the way, the main battery does trickle charge the 12V battery.
  • edited March 2018
    The function and usage of the Tesla 12V battery is much different than in an internal combustion vehicle and cannot be compared. Google it.
  • edited November -1
    Not a poor design. Most EVs work the same way. The main large battery charges the smaller 12v battery - no matter if charging or not.

    Now Tesla does have quite a bit of electronics that remain active even when parked - FOB detection, remote access via Cellular, processors on standby, etc. There is an option to reduce the power "energy savings", but then it take 30-60 seconds to boot up when you enter the car - something that most of us prefer not to use, Your antique ICE car usually doesn't have a fraction of the electronics that the Tesla does, and is why that don't have any of the cool features Tesla offers either.

    These features take some power, and requires charging that 12v battery more frequently - about 3 to 5 times a day. The battery is a special deep discharge battery - different from any ICE car to deal with the unique demands of the Tesla. That said, these 12v batteries usually only last 1-3 years. Tesla will replace it if under the 4 year warranty too, where most ICE warranties exclude the battery.

    I'm not sure about your farm equipment, but I suspect you prefer to drive the Tesla on the freeway. Different designs for different needs.
  • edited March 2018
    Sometimes seeking answers is better than making proclamations.
  • edited November -1
    How many miles and when was your car built?

    Last week, specifically on the 15th, I too got the 12v warning. This is the first time I have seen this. My car is 4 years old and at the time I had 107,794 miles on the car. I didn't give it a second thought because I had read all about this warning and the immense heads up this warning is giving. My car is going in for it's 4th Annual service tomorrow, so I will have tem take care of it then.

    Also, unless you are an expert on the differences between Tesla's 12v battery system and your tractors, perhaps we shouldn't be too quick to proclaim something as a poor design.
  • edited November -1
    You want to reduce 12volt charge cycles turn on power savings and turn off always connected. Turn off preconditioning and cabin overheat protection.

    Maybe auto present handles should be turned off too.

    Then let us know how you enjoyed jumping in the car and driving off, accessing via the app etc. Actually maybe turn off mobile access even.

    Could get really wild and do a complete shut down power off even.
  • edited November -1
    A Tesla will not "start right up" from a 12V battery because there's no starter. The 12V battery is used for other parts of the electrical system designed to run off 12 volts. The battery doesn't need cranking amps. The 12V battery does need to be working for the car to work, and if it can't hold a charge, it needs to be replaced. The car is telling you that it's less capable of holding a charge, not that your car won't run unless it's replaced immediately.

    The big difference between Tesla's 12V battery and those in an ICE is that Tesla will replace one for the length of the basic warranty. The other difference is that you won't get a warning with other cars that your battery will need replacing in a month.

    If you really want one immediately, you can look for another service center. If it were urgent enough that it might keep your car from working, I assure you that Tesla would rather have a battery flown in than have your car brought in on a flat bed and give you a loaner until they get a battery.
  • edited November -1
    Vehicle is less than a year old, less than 6k miles and is plugged in to the wall charger when not in use. Having to replace the 12V battery with that fact set is poor design, notwithstanding the points above. I bet in future versions from Tesla and ultimately competitors, they change that. Having said all that, love the car, but the fact is, they could have done this better. Also, Tesla dealer calling the morning of the appointment and cancelling because they don't have any 12V batteries and that they can't reschedule yet because they don't know when they will be getting them is poor customer service. They did tell me its not the same as a 12V on an ICE so I have no choice but to wait for them. Its not clear to me if its safe to drive the car in this condition.
  • edited November -1
    It’s absolutly safe to drive the car with the warning. I drove mine for 3 weeks before they replaced the battery without any issues.
  • edited March 2018
    Tesla does not manufacture the 12V battery, it is unfortunate that you got a bad one but that does necessarily indicate a bad design. My first S is still on it's original battery after 3 years, my CPO had it replaced after 2.5 years. I drove for three weeks with the battery warning.
  • edited March 2018
    @Haggy | March 22, 2018

    "The big difference between Tesla's 12V battery and those in an ICE is that Tesla will replace one for the length of the basic warranty. The other difference is that you won't get a warning with other cars that your battery will need replacing in a month."

    Actually there are increasingly more and more cars, not necessarily that new, which do have prognostics which will alert you to the 12V battery needing to be replaced. I have a 7 year old, MY 2011 Honda Odyssey which has such a feature. While the graphics are not as "fancy" as on my MS, it pops up a message in the information center on the instrument panel that states your 12V battery needs service. I know others that have similar vintage Odyssey's and their experience was getting it 3ish weeks before getting to no-start condition.
  • edited March 2018
    Update - 1) I escalated to execs through the portal. They got back to me and said as soon as they locate one they will come out and install it. That makes me feel better. 2) They would not tell me it is safe to drive in this condition. In response to my question all they would say is, "In the mean time I can't say for sure whether it is safe to drive or not". So I am choosing not to drive it. 3) In doing a google search there are a ton of posts about this issue, apparently its fairly common. That is unfortunate on such an engineering marvel, but I look forward to getting it back on the road with the new battery so I can enjoy it. If Spring weather would come so much the better!
  • edited March 2018
    The more typical admonition or lack thereof is that it is perfectly safe to drive for at least a month or two. Sounds like it may be a result of underuse as I've got well over 100,000 miles on my battery. I saw a 12V warning come up once several months ago and haven't seen it since.
  • edited March 2018
    "In the mean time I can't say for sure whether it is safe to drive or not"

    This sounds like someone covering their ass to a twitchy upset customer.
  • edited March 2018
    @OP just continue to enjoy your car by driving it. We are many in this forum that have continued to drive our car until we got the battery replaced without any problems or safety issues.
    The only limitation is that you can’t apply any OTA updates as long you have the warning.
  • edited March 2018
    VK859, don’t listen to us, we have only been driving these cars for years. Hell, many of us have been driving our cars longer than more than half of Tesla employees have been working for Tesla.....
  • edited November -1
    VK859 You've got about a month. You will get another message on your dash "car may not start". Park it then...
    Stinks that you got it at one year, probably bad battery, but it's covered under warranty. No worries.
  • edited March 2018
    To those claiming an ICE 12volt offers no warning, if one is vaguely observant cranking slows long before the battery dies. No cranking in a Tesla means a warning light is necessary.
    I have never seen an ICE battery died without the symptom of slow cranking.
    I am sure some batteries do just suddenly give up be they in Tesla or ICE but that is manufacturers defect and quite rare.
  • edited March 2018
    Should_I you are correct, typically there are signs as you pointed out. However, more and more, people don't pay attention to how their car runs. As cars became more and more reliable and required less service, people just started paying less attention. Personally I can tell by a sequence of events as to whether the problem is the battery or the alternator, but I am one of a dying breed of shade tree mechanics.

    So a 12V in an ICE up and dying with seemingly no warning, will happen more and more.
  • edited November -1
    I'll point out that a few automakers now use the same technology Tesla uses to provide an early warning of battery failure. I think all new Hondas use this tech now. Most car owners now expect the car to tell them when something is going bad, usually with an idiot light. Listening to what an ICE car is actually doing seems to be a lost art.

    I do like how the Tesla does provide clear warnings in English rather than a mostly useless check-engine light. I bet at least 50% of drivers don't even know or care what the check-engine light is.
  • edited November -1
    @TeslaTap - I agree with the value in clear warnings in English, but again Tesla is not alone in using text based displays. That is actually becoming very much the norm in many cars these days to have some form of a message center on the dash, and some have had one in some fashion going back 10 years.

    Now I will agree with you that most people do not know what the check engine light, or MIL, actually represents (I'd actually have pegged it higher than 50%). However, I also know from first hand involvement in my professional life that automakers have virtually zero discretion in how the MIL is used with it's behavior directly dictated by the OBD regulations. Given that compliance to the OBD regulation is tied to the emissions certification process, that's how Tesla and other BEVs have much more latitude over how they communicate powertrain related fault information.
  • edited March 2018
    OP, a "12V Battery Needs Service - Replace 12V Battery Soon" warning from a car that has been sitting for some period can be a normal thing.

    I went away for more than two weeks and came back to that message. Contacted SvC, ranger remotely checked my car and reset the warning. He told me that’s normal behavior if you don’t use the car for more than 10 days or more.

    Car works great, no more battery warnings (3 ¼-year old car.) YMMV.
  • edited November -1
    *Sorry for the extra “more”. No extra charge... ;-)
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