Lifestyle
Understanding the Tesla 12V Battery Service Warning
During the time when I was sitting on the sideline waiting patiently for delivery of my Model S, I read up on pretty much anything and everything related to the vehicle. I remember reading about 12V battery failures on the Model S, something Elon himself even commented on during one of the earnings calls.
RELATED: Tesla Model S 12V Lithium-Ion battery replacement (up to 70% lighter, 4x life)
It was reported that Tesla had chosen a poor vendor for the 12V battery which impacted early Model S owners but apparently this issue is still happening across later production vehicles. My Model S as well as several others that I personally know of received the 12V battery service indicator. For me this took place after 7 months and 18,000 miles of ownership.
Purpose of the Tesla 12V battery
Tesla Model S 12V Battery (source: TMC forum)
The 12V battery in the Model S performs many of the same duties as it would in any internal combustion engine (ICE) car.The connections to the 12V battery on a Model S appear to be a bit more complex than in a traditional ICE as seen in the following picture (source: TMC forum).
RELATED: Why Tesla’s lead acid 12V battery needs to be lithium-ion based
The 12V battery maintains power for critical systems when the main battery pack is damaged or disabled. It powers the hazard lights, airbags, door locking and unlocking operations, as well as other critical componets of the Model S. The 12V battery also ensures that electronics are “awake” and listening to the key FOB in order to automatically lock and unlock the vehicle based on proximity. It also allows the car to maintain its 3G connection for remote access when the rest of the vehicle is powered off. If the 12V battery happens to fail, it will isolate the main battery pack from the car and prevent charging. This is a safety feature of the Model S designed to help protect first responders in the event of an accident.
What does my warning mean?
The “12V Battery Needs Service” warning can indicate a number of problems and the only way to truly understand the reason for the alert is to call Tesla Service (they’re available 24×7) and have them pull the logs. This is something that Tesla service can diagnose remotely.
Tesla 12V battery terminal
In severe cases Tesla Service will tell you to stop driving the car, but generally it’s an indication that the voltage level has dropped below a certain threshold but the vehicle can continue to operate normally until replaced. In the rare event that the the 12V battery dies while driving, the car will become disabled and will require a jump start to power on again. Our friend Kman has a good video on getting access to the terminals behind the nosecone to jump start the 12V, but please consult Tesla service and take caution before attempting this on your own.
Depending on the severity of the issue, there may be a 2-3 week lead time before Tesla Service replaces the 12V battery.
Many owners manage to get the battery replaced quickly, but in my case a busy Tesla Service Center combined with the fact that it was Thanksgiving holiday during a snowy New England week, had me driving with the warning light on for almost 2 weeks (about 1,000 miles) without encountering any issues.
Another interesting point to note is that Tesla may call you before you even see 12V battery service warning. Multiple owners have reported this proactive stance in advance of a warning which is great to see. Evidently Tesla’s early warning threshold is supersedes the trigger that kicks off the dash indicator.
Why are the 12V batteries failing?
Some owners are on their 3rd 12V battery already. Many others are reporting failures at the 1 year mark. In ICE cars you can normally expect about 4 years of life before needing to replace the 12V battery which begs the question – why are Tesla 12V batteries failing?
Some of the failures have been in the DC to DC converter that charges the 12V battery through the main battery pack. That converter can be seen as an equivalent to the alternator in your traditional ICE car. However, this doesn’t seem to be the main cause of the 12V battery failures. Current conjecture is that vampire load and the excessive strain on the 12V are causing the reliability issues.
Tesla may have a lingering design issue in their use of the 12V battery.
From my reading, I think they upgraded the quality of the battery in the earlier models but we’re still facing the same underlying design issue in the way the 12V is stressed. Can Tesla fix the way the 12V battery is used with software updates alone? We don’t know, but fortunately they’re taking care of all of the replacements in the meantime. Unless they can address it remotely via software updates, there could be a factory “recall” brewing (and I use this term loosely).
Either way, Tesla should be more upfront about these issues and let owners know what they’re doing to address the underlying problem.
Getting the 12V battery serviced
From everthing I’ve heard and experienced through my own Model S, the replacement including labor and parts is 100% covered by Tesla.
Tesla Service can handle the replacement at your location, but given the poor weather conditions here in New England, I opted to have them pick up my Model S and do the replacement in the comfort of their own Service Center. They were able to service it within the same day, and to Tesla fashion they also updated/fixed a bunch of other minor things for free, while at it.
Summary
The 12V battery is a relatively inexpensive part in the Model S and is fairly simple to replace, but the bigger concern is why they seem to be failing so quickly. It isn’t a major issue for now but certianly something we should continue monitoring as concerned Model S owners.
I’ve started a poll over on TMC to see what kind of failure rate we’re seeing on the 12V battery so feel free to contribute to it or use it as a way monitor progress. So far over 75% of respondents have had their 12V battery replaced within 2 years.
Elon Musk
Tesla FSD is about to know your specific house and neighborhood better than any map
Tesla confirmed it is building a feature that lets you teach your car where to go.
Tesla is building a feature that will let drivers talk to their car in plain language and teach it exactly what to do, with the vehicle remembering those instructions for every future trip. Tesla VP of AI Software Ashok Elluswamy confirmed it this week on X after a user pointed out one of FSD’s most persistent real-world limitations is that the system has no way to receive contextual instructions the way a human driver would.
“FSD would be twice as useful in neighborhoods if I could actually talk to the car and tell it which driveway to pull into, the same way I would with a person driving me home. Right now, there isn’t really an input for telling Tesla what color the house is or giving it specific context like that. Google Maps is also notorious for putting pins on houses that aren’t actually yours.” Tesla owner Chris further noted, “It would be so cool if I could talk to the car while going down my street and say something like, ‘It’s the white house on the left, just past that SUV,’ and then have FSD remember that for next time.”
FSD would be twice as useful in neighborhoods if I could actually talk to the car and tell it which driveway to pull into, the same way I would with a person driving me home.
Right now, there isn’t really an input for telling Tesla what color the house is or giving it specific…
— Chris (@ChrissGPT) July 8, 2026
This feature would carry more weight than it might seem. Grok has been available inside Tesla vehicles since July 2025, expanded to European vehicles in February 2026, and gained a hands-free “Hey Grok” wake word with location-based reminders and natural-language navigation in the Spring 2026 update. But up to this point, Grok has had no authority over how FSD actually drives. Lane changes, braking, speed, and parking maneuvers remain entirely within FSD’s autonomous decision-making loop. What Elluswamy confirmed is that the next step pushes Grok into a supervisor role, one that translates spoken intent directly into driving decisions.
Tesla teases greater Grok FSD integration and ‘Banish’ feature ‘in about 3 months’
Elluswamy acknowledged at a January 2026 conference that while fully integrated voice control is on Tesla’s roadmap, “it opens up an entire area of testing that we have to do. For example, you shouldn’t be able to tell the car to crash, and it shouldn’t crash.” Elon Musk subsequently confirmed on June 23 that Grok voice commands will pass to FSD’s planning layer by September 2026, a three month timeline from confirmation to deployment.
The deeper significance is what this does for Tesla’s AI training flywheel. Every time an owner corrects FSD with a spoken instruction and the car learns and remembers it, that interaction becomes a data point covering an edge case that no simulation or scripted test could have generated. A fleet of millions of Tesla vehicles crowdsourcing hyper-local contextual knowledge, which driveway, which gate entrance, which side of the street, builds a layer of geographic and behavioral intelligence that competitors without a comparable fleet simply cannot replicate at the same speed or scale.
As Teslarati has reported, Tesla’s Cybercab and robotaxi operations have expanded to Miami following the Austin launch, with rider profiles already collecting preference data. Voice-taught contextual instructions linked to individual rider profiles means a Cybercab could eventually know before it arrives exactly which entrance to use, where to wait, and how to navigate the final hundred feet of any trip it has made before.
Lifestyle
Tesla app update makes Robotaxi ownership make a lot more sense
Tesla’s app now shows a live indicator when your car is actively driving itself.
A recent Tesla app update, released last week (4.58.5), gives visibility on whether a vehicle is navigating in its semi-autonomous mode or being drive by a human driver. The updated app now displays a live “Self-Driving” indicator in bright blue text directly beneath the vehicle’s speed readout whenever Full Self-Driving is actively engaged, along with the signature glowing blue navigation path that FSD users see on the main touchscreen. It is a small visual update with meaningful implications for how Tesla owners monitor their vehicles remotely.
The feature was first spotted in the wild by X user Jordan Camina, who shared video of a Hardware 3 Model S displaying the new animation through the app while driving. That detail is significant because it confirms the update is not limited to newer HW4 vehicles. It works across hardware generations, and Tesla confirmed it will eventually support all vehicles regardless of chip platform once both the app and vehicle software are updated. The vehicle side requires software version 2026.20.6.1, which has reached nearly 40% of the fleet so far, as monitored by NotaTeslaApp.
The feature makes the most practical sense when viewed through the lens of Tesla’s expanding robotaxi operation. In a robotaxi context, the owner of a vehicle generating ride revenue has a direct financial and safety interest in knowing whether their car is operating under autonomous control at any given moment. The app’s new FSD indicator gives fleet owners exactly that visibility, the same way a logistics company monitors whether a delivery driver is following the planned route. It also carries implications for Tesla’s insurance model. Tesla’s own insurance product prices premiums in part based on FSD engagement rates, and real-time visibility into when FSD is active creates a feedback loop that could eventually tie directly into policy pricing. For individual owners who have opted their personal vehicles into the robotaxi network, the update effectively turns the Tesla app into a fleet management dashboard, one that tells you whether your car is earning money, whether it is driving itself to do it, and whether everything is operating the way it should from wherever you happen to be.
Tesla expands Robotaxi to Florida, marking its third state for autonomy
As Teslarati has reported, Tesla launched unsupervised robotaxi rides in Miami this summer, a milestone that makes a remote FSD status indicator significantly more practical than a cosmetic feature. When a vehicle is operating as a robotaxi without a driver present, the owner or fleet operator needs a reliable way to confirm autonomy is engaged. The app now provides exactly that.
As noted by NotATeslaApp, The update also arrived alongside a hint buried in the same app version that Tesla plans to use the cabin camera to verify driver identity before FSD can be activated. Pairing identity verification with a live autonomy status indicator points toward the infrastructure Tesla is building for a fleet of driverless vehicles that owners can monitor the way you would track a package delivery.
Elon Musk
The Boring Company just doubled its tunneling power in Nashville
The Boring Company’s Prufrock MB2 is commissioned and ready to mine beneath Nashville’s streets.
The Boring Company’s second tunnel boring machine, Prufrock MB2, is officially ready to dig in Nashville. The company confirmed the news on X, posting: “Prufrock-MB2 is ready to mine in Nashville! MB2 commissioning is complete, including the brief 11 rpm rotation shown here. Will MB2 catch up to MB1, who had quite the head start? And Prufrock-MB3 ships in August!”
MB2 arrives with meaningful improvements over its predecessor. Lessons learned from the launch and operation of MB1 have already been applied to MB2 to improve efficiency and prepare the machine for launch.
Traditional tunnel boring machines operate in a stop-and-go cycle, digging roughly five feet, halt, erect precast concrete segments to line the tunnel wall, then resume. That repeated interruption is one of the main reasons conventional tunneling is slow and expensive. Prufrock is designed to install the tunnel liner simultaneously with mining, eliminating the need to stop every five feet. The machine also skips the need for excavated launch pits. Prufrock arrives on a truck, tilts down, and launches into the ground within 24 hours. And when the tunnel is complete, it emerges from the ground and drives to its next launch site on a trailer, eliminating the need for expensive cranes or pit excavation. The machine is also fully electric and runs with zero people in the tunnel during normal operations, controlled remotely from a surface operations center.
Prufrock-MB2 is ready to mine in Nashville! MB2 commissioning is complete, including the brief 11 rpm rotation shown here.
Will MB2 catch up to MB1, who had quite the head start?
And Prufrock-MB3 ships in August! pic.twitter.com/TTrMql2aRg
— The Boring Company (@boringcompany) June 17, 2026
It won’t be long before we hear of another major update on The Boring Company’s Music City Loop project – a planned underground transit network beneath Nashville that would move passengers in electric vehicles through a series of tunnels at highway speeds, and bypassing surface traffic entirely. Nashville was selected in part because of its strong rock conditions that suits the Prufrock machines well, and relatively less regulatory hurdles.
Progress has been steady on multiple fronts. All 37 permits and approvals required ahead of tunneling have been obtained, out of 45 total. Key wins include a fully executed TDOT tunnel permit authorizing 25 miles of tunnel, unanimous airport authority approval for a Nashville International Airport station, and the city’s first residential station agreement serving downtown tower residents.
With MB1 already tunneling, MB2 now commissioned, and MB3 shipping in August, Nashville is becoming something of a live proving ground for scaled tunnel boring. The broader ambition is not limited to one city. The Boring Company’s stated goal is to make underground transportation a practical alternative to surface roads across major metro areas. Nashville is one of many cities, including a successful Las Vegas tunnel system, where that idea is being put to the test at real speed.
Tesla confirms crucial detail of Miami Robotaxi launch
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