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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.
“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.
Elon Musk
Elon Musk shuts down talk of TSMC taking over Terafab
Musk says Tesla and SpaceX will build and run Terafab, with TSMC limited to renting.
Elon Musk has drawn a firm line around who will be in charge of Terafab, the giant chip factory Tesla and SpaceX are planning in Texas.
Musk replied to a post on X arguing that Taiwan Semiconductor Manufacturing Company (TSMC) would most likely end up owning and operating the plant. “No, we will build and run the fab. Let there be ZERO doubt about that,” Musk wrote. “Maybe TSMC subleases part of the Terafab if they want, but nothing more than that.”
In plain terms, a sublease means TSMC could rent a section of the complex to make chips, similar to a tenant renting one floor of an office tower. The building, the equipment decisions and the daily operation would stay with Tesla and SpaceX.
@herbertong @thejefflutz No, we will build and run the fab. Let there be ZERO doubt about that.
Maybe TSMC subleases part of the Terafab if they want, but nothing more than that.
— Elon Musk (@elonmusk) October 7, 2026
The comment shuts down speculation that started last week. On October 2, tech journalist Tim Culpan reported that TSMC was exploring ways to help run Terafab’s factories. Musk responded the next day that it was “just discussions, but something may come of it,” as Teslarati reported at the time. That left room for a scenario where the world’s largest contract chipmaker took the wheel. Musk’s latest post closes that door.
Some background helps explain why this matters. Tesla designs its own AI chips today but pays outside companies like TSMC and Samsung to manufacture them. Musk unveiled Terafab in March as a joint project between Tesla, SpaceX and xAI, arguing that existing suppliers cannot expand fast enough to meet his companies’ future demand. The goal is to produce enough chips each year to supply one terawatt of computing power, roughly 50 times what the entire global AI chip industry produces now.
Those chips are meant for Tesla’s Optimus humanoid robots, the Cybercab and Full Self-Driving computers, along with chips for SpaceX’s planned data centers in orbit. Owning the factory means Musk’s companies would not have to compete with every other chip customer for time on someone else’s production lines.
Intel is still part of the picture. The company signed on in April to help design, build and package chips for the project, and CEO Lip-Bu Tan told Bloomberg this week that Intel will keep working on Terafab despite the TSMC chatter.
The project moved from concept to construction planning over the summer. In August, SpaceX confirmed the Grimes County site about an hour from Houston, sent the county a $10 million payment under its tax abatement deal and said civil work would begin shortly. The first phase carries a $16.8 billion price tag, and total spending across all phases could reach as much as $119 billion.
TSMC chairman C.C. Wei has said a new fab typically takes two to three years to build and another one to two years to reach full output. Tesla and SpaceX have never run one, which is why TSMC’s expertise drew so much attention. Musk’s answer suggests he would rather learn that process in house than hand control of a project this central to Tesla’s robotics and autonomy plans to an outside company.
Terafab Texas will be the largest and most valuable building on Earth by far.
And it will be stunningly beautiful. https://t.co/4NweOqTL7y
— Elon Musk (@elonmusk) August 6, 2026
Elon Musk
Trump to hand Elon Musk a top honor that traces back to JFK
Trump will award Elon Musk the National Medal of Science at Thursday’s White House summit.
Elon Musk is set to receive the highest honor the U.S. government gives to scientists and engineers.
President Donald Trump will present Musk with the National Medal of Science on Thursday at the White House’s Science: A New Golden Age Summit, Fox News Digital first reported on Wednesday. Google cofounder Sergey Brin, Nvidia CEO Jensen Huang and AMD CEO Lisa Su will receive the same medal, while Dell Technologies CEO Michael Dell and Microsoft CEO Satya Nadella will receive the National Medal of Technology and Innovation. A White House official later confirmed the list to Reuters.
“The Trump administration is grateful for the contributions of these incredible leaders in science and technology. These recipients are helping ensure America keeps leading the world in innovation,” White House spokesperson Liz Huston told Fox News.
FIRST ON FOX: Trump will award Elon Musk the National Medal of Science at the White House Thursday.
Sergey Brin, Jensen Huang and Lisa Su will also receive the science medal, while Michael Dell and Satya Nadella will receive the technology medal.
It marks Trump’s first time presenting the awards across either administration.
Full story here https://t.co/omnrLV0EwS
— Fox News Politics (@foxnewspolitics) October 7, 2026
It will be the first time Trump has presented either medal in his two terms. Congress created the National Medal of Science in 1959, and the National Science Foundation, which administers it, says 529 scientists and engineers have received it since. A presidential committee reviews nominees, but the president makes the final call.
Thursday’s group of medalists run or founded companies, and three of them sit at the center of the Super Intelligence hardware race that Musk competes in. Huang’s Nvidia supplies the GB300 chips filling SpaceX’s Colossus 2 cluster, while Su’s AMD is Nvidia’s biggest rival in data center GPUs.
Worth noting that Trump’s uncle, MIT physicist John G. Trump, received the National Medal of Science from President Ronald Reagan for his work on ionizing radiation and its uses in medicine and industry.
The Pentagon taps Elon Musk to design the battlefield of the future
For Musk, the medal is the latest sign of how far his relationship with Trump has come since their 2025 split over the “Big Beautiful Bill” and his exit from DOGE. Last week, he sat at Trump’s left during a White House lunch where AI executives signed a voluntary safety accord, and Defense Secretary Pete Hegseth named him to help lead the Pentagon’s Project Meridian study on the future of warfare. Musk has also adopted the administration’s new vocabulary, saying on Sunday that SpaceXAI will be renamed SpaceXSI after Trump ordered federal agencies to replace “artificial intelligence” with “super intelligence.”
Musk has collected science honors before, including the Stephen Hawking Medal for Science Communication in 2019.
Lifestyle
Tesla FSD changed its mind mid-intersection, and it may have saved a life
Tesla shares dashcam footage of FSD Supervised stopping mid intersection to avoid a T-bone crash.
Tesla is putting another Full Self-Driving save in front of its 24.8 million followers on X.
On Tuesday morning, Tesla’s main account shared a dashcam clip with the caption “FSD Supervised preventing T-bone crash.” The footage came from an owner posting as TheNewGrid, who described what happened at a stop sign: “I looked at the car coming to the stop sign figured they would stop, my car went, then came to a stop mid intersection as they flew by. Had I been manually driving this would have resulted in a crash.”
The sequence is the notable part. FSD had already started crossing when the other driver ran the stop sign. Instead of pressing on, the car braked hard in the middle of the intersection and let the crossing vehicle pass in front of it. By the owner’s own account, they had made the same assumption the software initially made, that the other car would stop, and would not have corrected in time.
FSD Supervised preventing T-bone crash
— Tesla (@Tesla) October 6, 2026
The clip is the latest in a run of safety posts Tesla has amplified over the past several days. On Saturday, the company shared a video from Selling Sunset star Jason Oppenheim, who sold his Bentley for a Model Y and said he was buying Teslas with FSD for 10 of his employees. Ashok Elluswamy, who leads Tesla AI, followed up by writing that Tesla self-driving “reacts to other people cutting into your path with super-human response times.” On Monday, a Cybertruck owner posted footage of FSD moving across three lanes from a red light to clear a path for an ambulance approaching from behind.
This recent clip also lands a few weeks after Tesla began shipping Automatic Collision Evasion with FSD v14.3.9, a feature that can activate FSD on the driver’s behalf when a frontal collision is imminent or the driver appears distracted. Elluswamy said in September that “even earlier prediction of hazards, even faster reaction time and overall significantly better safety and collision avoidance” are coming with v15, the release Tesla has tied to round the clock Robotaxi operation.
The safety messaging matters beyond social media. Tesla has said FSD Supervised was 4.1 times less likely to crash than manual driving across 100 million kilometers on European roads, and it has been putting those figures in front of regulators. Eight EU countries have now approved FSD Supervised, with Croatia the most recent, but the EU’s bloc-wide vote originally set for October 6 has been pushed to December at the earliest.
FSD Supervised is still a Level 2 system, and the driver remains responsible at all times. Even heavy users find reasons to step in. Teslarati’s Joey Klender, who uses FSD for about 76 percent of his driving, laid out five recurring issues on Tuesday that still prompt him to intervene. Clips like this one show the other column of that ledger: moments where the software caught a mistake a human was about to make.
Elon Musk shuts down talk of TSMC taking over Terafab
Trump to hand Elon Musk a top honor that traces back to JFK
Tesla FSD changed its mind mid-intersection, and it may have saved a life
The Pentagon taps Elon Musk to design the battlefield of the future
Tesla Roadster’s new patent preps white-knuckle speeds, keeping it grounded
