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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.
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Tesla Optimus V3 gets early third-party feedback, and it’s eye-opening
Jason Calacanis’ remarks, which were shared during a discussion at CES 2026, offered one of the first third-party impressions of the yet-to-be-unveiled robot
Angel investor and entrepreneur Jason Calacanis shared some insights after he got an early look at Tesla’s upcoming Optimus V3. His remarks, which were shared during a discussion at CES 2026, offered one of the first third-party impressions of the yet-to-be-unveiled robot.
Calacanis’ comments were shared publicly on X, and they were quite noteworthy.
The angel investor stated that he visited Tesla’s Optimus lab on a Sunday morning and observed that the place was buzzing with energy. The investor then shared a rare, shocking insight. As per Calacanis, Optimus V3 will be so revolutionary that people will probably not even remember that Tesla used to make cars in the future.
“I don’t want to name drop, but two Sundays ago, I went to Tesla with Elon and I went and visited the Optimus lab. There were a large number of people working on a Sunday at 10 a.m. and I saw Optimus 3. I can tell you now, nobody will remember that Tesla ever made a car,” he noted.
The angel investor also reiterated the primary advantage of Optimus, and how it could effectively change the world.
“They will only remember the Optimus and that he is going to make a billion of those, and it is going to be the most transformative technology product ever made in the history of humanity, because what LLMs are gonna enable those products to do is understand the world and then do things in the world that we don’t want to do. I believe there will be a 1:1 ratio of humans to Optimus, and I think he’s already won,” he said.
While Calacanis’ comments were clearly opinion-driven, they stood out as among the first from a non-Tesla employee about Optimus V3. Considering his reaction to the humanoid robot, perhaps Elon Musk’s predictions for Optimus V3 might not be too far-fetched at all.
Tesla has been careful with its public messaging around Optimus V3’s development stage. Musk has previously stated on X that Optimus V3 has not yet been revealed publicly, clarifying that images and videos of the robot online still show Optimus V2 and V2.5, not the next-generation unit. As for Calacanis’ recent comments, however, Musk responded with a simple “Probably true” in a post on X.
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Tesla taps Samsung for 5G modems amid plans of Robotaxi ramp: report
The move signals Tesla’s growing focus on supply-chain diversification and next-generation communications as it prepares to scale its autonomous driving and robotaxi operations.
A report from South Korea has suggested that Samsung Electronics is set to begin supplying 5G automotive modems to Tesla. If accurate, this would mark a major expansion of the two companies’ partnership beyond AI chips and into vehicle connectivity.
The move signals Tesla’s growing focus on supply-chain diversification and next-generation communications as it prepares to scale its autonomous driving and Robotaxi operations.
Samsung’s 5G modem
As per industry sources cited by TheElec, Samsung’s System LSI division has completed development of a dedicated automotive-grade 5G modem for Tesla. The 5G modem is reportedly in its testing phase. Initial supply is expected to begin in the first half of this year, with the first deployments planned for Tesla’s Robotaxi fleet in Texas. A wider rollout to consumer vehicles is expected to follow.
Development of the modem began in early 2024 and it required a separate engineering process from Samsung’s smartphone modems. Automotive modems must meet stricter durability standards, including resistance to extreme temperatures and vibration, along with reliability over a service life exceeding 10 years. Samsung will handle chip design internally, while a partner company would reportedly manage module integration.
The deal represents the first time Samsung has supplied Tesla with a 5G vehicle modem. Tesla has historically relied on Qualcomm for automotive connectivity, but the new agreement suggests that the electric vehicle maker may be putting in some serious effort into diversifying its suppliers as connectivity becomes more critical to autonomous driving.
Deepening Tesla–Samsung ties
The modem supply builds on a rapidly expanding relationship between the two companies. Tesla previously selected Samsung’s foundry business to manufacture its next-generation AI6 chips, a deal valued at more than 22.7 trillion won and announced in mid-2025. Together, the AI chip and 5G modem agreements position Samsung as a key semiconductor partner for Tesla’s future vehicle platforms.
Industry observers have stated that the collaboration aligns with Tesla’s broader effort to reduce reliance on Chinese and Taiwanese suppliers. Geopolitical risk and long-term supply stability are believed to be driving the shift in no small part, particularly as Tesla prepares for large-scale Robotaxi deployment.
Stable, high-speed connectivity is essential for Tesla’s Full Self-Driving system, supporting real-time mapping, fleet management, and continuous software updates. By pairing in-vehicle AI computing with a new 5G modem supplier, Tesla appears to be tightening control over both its hardware stack and its global supply chain.
Tesla’s new Full Self-Driving pricing strategy will eliminate one recurring complaint that many owners have had in the past: FSD transfers.
In the past, if a Tesla owner purchased the Full Self-Driving suite outright, the company did not allow them to transfer the purchase to a new vehicle, essentially requiring them to buy it all over again, which could obviously get pretty pricey.
This was until Q3 2023, when Tesla allowed a one-time amnesty to transfer Full Self-Driving to a new vehicle, and then again last year.
Tesla is now allowing it to happen again ahead of the February 14th deadline.
The program has given people the opportunity to upgrade to new vehicles with newer Hardware and AI versions, especially those with Hardware 3 who wish to transfer to AI4, without feeling the drastic cost impact of having to buy the $8,000 suite outright on several occasions.
Now, that issue will never be presented again.
Last night, Tesla CEO Elon Musk announced on X that the Full Self-Driving suite would only be available in a subscription platform, which is the other purchase option it currently offers for FSD use, priced at just $99 per month.
Tesla is shifting FSD to a subscription-only model, confirms Elon Musk
Having it available in a subscription-only platform boasts several advantages, including the potential for a tiered system that would potentially offer less expensive options, a pay-per-mile platform, and even coupling the program with other benefits, like Supercharging and vehicle protection programs.
While none of that is confirmed and is purely speculative, the one thing that does appear to be a major advantage is that this will completely eliminate any questions about transferring the Full Self-Driving suite to a new vehicle. This has been a particular point of contention for owners, and it is now completely eliminated, as everyone, apart from those who have purchased the suite on their current vehicle.
Now, everyone will pay month-to-month, and it could make things much easier for those who want to try the suite, justifying it from a financial perspective.
The important thing to note is that Tesla would benefit from a higher take rate, as more drivers using it would result in more data, which would help the company reach its recently-revealed 10 billion-mile threshold to reach an Unsupervised level. It does not cost Tesla anything to run FSD, only to develop it. If it could slice the price significantly, more people would buy it, and more data would be made available.
Tesla Optimus V3 gets early third-party feedback, and it’s eye-opening
Tesla taps Samsung for 5G modems amid plans of Robotaxi ramp: report
