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Why Tesla’s lead acid 12V battery needs to be lithium-ion based
It’s a prominent issue surrounding the electric vehicle market that the old-school lead acid battery just isn’t appropriate for new technology vehicles. Many users of electric vehicles, especially Tesla owners, have cited concerns with the poor performance of their 12V or low-voltage battery, oftentimes requiring annual replacement.
In contrast, a lead acid battery in a traditional internal combustion engine (ICE) vehicle generally has a 4 year life-cycle, but why?
RELATED: Tesla Model S 12V Lithium-Ion battery replacement (up to 70% lighter, 4x life)
First off, some of the most important factors to consider in longevity of a battery are “cycle-life”, environmental conditions, discharge/charge rates and calendar-life; cycle-life is how many times the battery can be drained and recharged in its life. Environmental conditions include temperature and humidity. Discharge/charge rates are the amperages going out of and into the battery respectively.
There are two major differences between the way an ICE vehicle uses its 12V battery and the way an EV uses its 12V battery:
“OFF” state discharge and cycling frequency
ICE Vehicle: generally has a very low 12V load while the vehicle is in the “off” state, often this load doesn’t exceed a few watts and doesn’t present a major challenge for the 12V battery to maintain.
Electric Vehicle: The 12V load while in the off-state is often much higher due to advanced computer systems that are running to maintain the high-voltage battery, keep vehicle “connected” (all EV have some remote access features), maintain charging and BMS (Battery Management System) communications, etc. In fact a Tesla Model S/X puts about 50 Watts of load on the 12V system when the vehicle is in the “off” state. 50 Watts equals about 4.5 Amps of discharge on the 12V battery, this drains the battery down relatively rapidly and requires the 12V battery be “recharged” by the high-voltage battery regularly, this usage pattern results in many cycles being placed on the battery.
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“ON” state utilization and purpose
ICE Vehicle: The 12V battery is used to initiate the ICE (start the car) and is designed for putting out large amounts of current to accommodate this process. Once an ICE vehicle is in the “on” state, it relies on an alternator to power all of the 12V sub-systems and also maintain the voltage of the 12V battery.
Electric Vehicle: The 12V is subjected to (practically) no additional load while the vehicle is being turned “on”, and although most vehicles are designed with DC/DC converters (which act as alternators) it is often an engineering design choice to reduce load on the DC/DC converter by minimizing the frequency with which it is utilized. This also extends the driving range of the vehicle because none of the precious high-voltage battery capacity is being shunted to non-driving tasks. Due to this usage profile the 12V battery is subjected to relatively low discharge and recharge currents.
When you combine the high number of cycles and the low current requirements of the electric vehicle 12V battery system you arrive at a completely different battery need than that of an ICE vehicle. Lead Acid batteries are very good at high discharge and low cycle count life-styles, this is their bread and butter and this is where they last a long time and provide the most bang for the buck (cheap cost and decent product life-cycle), but they aren’t lasting in electric vehicles.
The electric vehicle 12V battery system is one that is best suited by a battery capable of tremendous cycle-life as the main design goal. The battery chemistry that suits this usage scenario best? Lithium! Lithium battery technology is specifically very good at being cycled many times and continuing to provide minimal capacity loss and degradation. This, along with reduced weight, is why these batteries are used for the high-voltage battery packs, cell-phones, laptops, medical equipment and cars where batteries are being cycled frequently and longevity is important.
Editor’s note: This post was submitted into our network by Tesla Model S owner Sean Scherer. Having suffered an unfortunate incident in his Model S that left him stranded because of a faulty 12V battery, Sherer began on a mission to create a lithium-ion based 12V battery solution that was not only more reliable than the traditional lead acid battery, but better suited for the demands of a Tesla Model S, Model X, and electric vehicles in general. He began BattMobile Batteries, who have made it their mission to improve adoption of electric vehicles by solving some of the small details that has been missed by EV manufacturers.
We’ve also included a video tutorial on how to replace the Model S 12V battery.
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Elon Musk’s massive Terafab project, which will be the first true conglomeration between each of his major entities, is set to get its final location soon, the CEO said on Tesla’s recent earnings call.
“The Terafab, we expect to announce a location soon, and provide more details about our plans in that regard. We’ll leave that to the product, the launch announcement rather than try to squeeze it into an earnings call,” Musk said last Wednesday.
Tesla Terafab set for launch: Inside the $20B AI chip factory that will reshape the auto industry
Terafab was announced by Musk back in March and was essentially a massive, vertically integrated semiconductor manufacturing project that would provide all the chips the three companies needed for their AI initiatives without needing third-party companies.
The plant will produce over 1 terawatt of AI compute each year, and will help back up projects like Optimus, Full Self-Driving, and other AI-based projects that Musk’s companies are working on.
In April, less than a month after the project was launched, Intel announced it would join the project, contributing manufacturing expertise and consulting to Terafab as a whole. Intel is one of three chip manufacturers that produce sub-5 nanometer chips at scale. TSMC and Samsung are the other two.
However, there was no true indication of where Terafab would end up, but most believe it will likely be somewhere in Texas. Business Insider has reported that SpaceX plans to build out Terafab in Grimes County, Texas, but this is unconfirmed.
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Musk confirmed recently that it would not be on Giga Texas property, as it is simply too large.
The sheer scale of TERAFAB is going to be insane.
Elon said it wouldn’t be suitable for anywhere on Giga Texas property because it’s too big:
“We couldn’t possibly fit the Terafab on the GigaTexas campus. It will be far bigger than everything else combined there.
Several… pic.twitter.com/79GbhNNuf4
— TESLARATI (@Teslarati) March 23, 2026
Terafab holds much of Musk’s grand ambitions for the future within its construct. It holds so much responsibility for the future and the biggest projects that Musk’s companies can imagine.
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“I think this is a very big announcement and it deserves to have its own day in the spotlight and not be squeezed into an earnings call,” he said. “I do think Terafab is going to be an amazing initiative and a necessary one, and one without which we will be constrained in our ability to scale Optimus production, because we simply won’t have enough AI chips.”
He continued by stating that Terafab is necessary for scaling Optimus, which Musk said could be the biggest product of any kind of all time. “It’s crucial to solve that, and we’ll have to solve memory, logic, and packaging in order to scale Optimus.”
SpaceX performed a secret test on a specific portion of Starship with its recent 13th test flight last week, CEO Elon Musk revealed.
Starship’s 13th test flight took place last Friday, and in many aspects, it was one of the most overwhelmingly successful launches in the project’s history.
All of the mission objectives were met without incident, both the Super Heavy Booster and Ship managed to perform safe splashdowns in the Gulf of America and the Indian Ocean, respectively, and the deployment of Starlink satellites came and went without any complications.
— Elon Musk (@elonmusk) July 25, 2026
However, there was more on the agenda for SpaceX with Flight 13. Musk revealed an internal test of the ship’s heat shield tiles, as the space exploration company wanted to push them to the limits after previous issues.
Many noticed that Starship’s initial launch seemed to be more accelerated than normal, and that was not a mistake. Musk revealed that SpaceX decided to give Flight 13 an intentionally aggressive acceleration rate in an effort to test how well the tiles would remain attached to the ship:
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This flight intentionally had much higher acceleration to test how well the heat shield tiles would remain attached at high dynamic pressure.
Test was successful.
— Elon Musk (@elonmusk) July 25, 2026
SpaceX had issues with some of the heat shield tiles remaining attached early on in the Starship program. The first six test flights presented some kind of anomaly with them, so the company’s big focus with them was to figure out a way to keep them intact through the duration of the flight.
Things truly improved as Flight 10 showed that ceramic tiles generally stayed attached to the ship far better due to refined attachment, as SpaceX utilized pins instead of adhesives. Flights 10 through 13 truly showed some clear progress with the heat shield tiles, and this latest test seems to be where some real progress was noticed, especially by Musk.
The 13th Starship launch last Friday was the second with Starship V3, SpaceX’s latest and greatest iteration of the spacecraft. Goals and ambitions are getting even grander as the project continues to progress. Musk has already hinted that SpaceX will likely try to catch Starship with Flight 14.
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Elon Musk
Tesla FSD takes owner on a 20,000+ mile joy ride
Tesla owner David Moss just pushed his intervention free FSD streak past 20,000 miles total.
Tesla Model 3 owner David Moss has spent the better part of eight months turning his vehicle into a rolling stress test for Full Self-Driving, and this week he pushed his single, continuous FSD streak past 20,000 miles without a human intervening.
Moss, a Tacoma, Washington resident who sells LiDAR scanning equipment for a living, first drew wide attention in December 2025 when he logged 10,000 consecutive miles on FSD v14.2. Days later he drove from the Tesla Diner in Los Angeles to Myrtle Beach, South Carolina, covering 2,732 miles in two days and 20 hours with zero disengagements, the first verified coast to coast autonomous drive in Tesla’s history. Tesla even featured the trip as an official customer story in March. That original streak eventually reached 12,961 miles across 30 states before ending in rural Wisconsin in January, when snow and single digit temperatures forced Moss to take over.
Tesla FSD successfully completes full coast-to-coast drive with zero interventions
He started over, and this run has gone further. In late May, Moss drove 3,760 miles across Canada with two companions, from Horseshoe Bay in Vancouver to a Tesla showroom in Halifax, again without a single intervention, a trip Tesla AI software VP Ashok Elluswamy publicly congratulated him for on X. In June, he pushed the same unbroken streak south, aiming to link the Canadian border to the Mexican border, and crossed 10,000 miles on Tesla’s newly added in car streak counter along the way, the first driver to do so since Tesla began showing confetti animations for the feature.
20,000 Mile Tesla FSD Screen Streak!
Special thank you to @DevinOlsenn, @scotsrule08, & @OwenSparks for helping co drive during all these fun adventures these last couple of months
Also thank you to @wholemars for always tracking me along the journey verifying it all with his… pic.twitter.com/CZ2yO6Ev0X
— David Moss (@DavidMoss) July 27, 2026
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It’s worth noting that every mile is logged through the FSD Database, a community run tracker built by Tesla influencer Omar Qazi, well known as @WholeMars on X, that pulls telemetry straight from the car and records disengagements down to a tenth of a mile. That verification is what separates Moss’s numbers from casual claims on social media.
The streak itself is a fairly recent addition to Tesla’s software. FSD v14.2 introduced a Self Driving Stats panel tracking the ratio of autonomous to manual miles, and v14.3.4 added the live streak counter in June, which resets the moment a driver brakes, wrenches the wheel or cancels navigation. Reaching 20,000 miles on that counter means a single Tesla drove itself through countless highways, city grids, construction zones and Supercharger stalls without a single reset.
Moss has said the goal was never to set a record for its own sake, but to show, mile by verified mile, what the software can already do.
Musk’s massive Terafab project will get final location soon
Elon Musk reveals SpaceX performed secret Starship test on Flight 13
