News
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.
A Tesla Semi was involved in a fatal collision on U.S. Highway 50 in Dayton, Nevada, on Sunday, June 28, 2026, marking the first known fatal crash involving the electric Class 8 truck. The incident occurred around 7:20 a.m. at the intersection with Traditions Parkway, approximately 40 miles east of Reno and close to Tesla’s Gigafactory Nevada.
According to the Lyon County Sheriff’s Office and the Nevada State Police Highway Patrol, a semi-truck struck two passenger vehicles stopped at a traffic signal. The truck hit the vehicles from behind. Two people were pronounced dead at the scene, and a third person suffered life-threatening injuries and was flown to a hospital, Forbes reported.
Preliminary statements gathered at the scene by the Lyon County Sheriff’s Office suggested the truck driver may have fallen asleep at the wheel. However, the Nevada Highway Patrol, which is leading the investigation, stated that the official cause has not yet been determined.
Additional information is expected to be released early the following week. The truck was seized for evidence as part of the ongoing probe.
Responders at the scene included deputies from the Lyon County Sheriff’s Office, personnel from the Nevada Highway Patrol, Central Lyon County Fire Department, and the Nevada Department of Transportation. The crash led to the temporary closure of U.S. 50 in both directions.
The Tesla Semi is Tesla’s battery-electric heavy-duty truck, produced at the nearby Gigafactory in Nevada. Authorities initially described the vehicle as a semi-truck; its make was subsequently confirmed through reporting and scene identification; an interesting bit of information here, as the Semi is not yet available publicly and many do not know that Tesla builds electric trucks.
The investigation remains active, with no further official details on contributing factors or vehicle systems released as of early July 2026.
This incident highlights ongoing scrutiny of commercial vehicle safety on Nevada highways, particularly involving fatigue. Law enforcement continues to gather evidence and witness statements.
Tesla has expanded its Robotaxi program to Miami, Florida, marking the third state the autonomous ride-hailing platform has made its way to since launching last Summer.
Tesla announced today that the Robotaxi suite would now officially launch rides in a geofence in Miami:
🚨 Tesla’s “Long Weekend” continues with a HUGE announcement regarding Robotaxi!
It’s now in Miami!
Miami joins Austin, Dallas, Houston, and the Bay Area! https://t.co/ujjYjJT3Im pic.twitter.com/yPe1ZdSQIE
— TESLARATI (@Teslarati) July 3, 2026
The first geofence in Miami covers approximately 10 to 14 square miles. The area appears to be focused on western and central Miami, including Miami International Airport (MIA). It also includes popular routes like SR 826 (Palmetto Expressway), US 41 (Tamiami Trail), and connectors such as SR 968, 953, 959, and 972.
This is Tesla’s initial Miami launch zone, smaller and more targeted than some competitors’ areas (for example, Waymo’s initial rollout was broader in eastern neighborhoods). It prioritizes high-traffic, airport-linked routes before wider expansion.
The expansion is a huge signal for Tesla that it is now operating in Florida, a heavy-traffic state with many tourist areas, including Fort Lauderdale, Palm Beach, and the Boynton area, all of which are coastal and will attract perhaps millions of tourists in any given year.
¿Qué lo que Miami?
Robotaxi now available in Miami pic.twitter.com/P1m283seZU
— Tesla Robotaxi (@robotaxi) July 3, 2026
The Tesla Robotaxi network launched last year on June 22, in Austin, Texas, beginning limited commercial operations in that city. It expanded shortly thereafter into the San Francisco Bay Area of California in late July 2025, marking entry into a second state with service covering key areas such as San Francisco, San Jose, and Berkeley.
Full commercial service was achieved in Austin by November 18, 2025, strengthening its presence within Texas before further growth.
In 2026, the network continued expanding across Texas with the addition of Dallas and Houston on April 18, significantly broadening its footprint in the state. This new launch into Miami marks Tesla entering a new state and bringing active locations to include Austin, Dallas, Houston, San Antonio in Texas, and the Bay Area in California.
These sequential expansions have steadily increased the network’s reach across major metropolitan areas in Texas, California, and Florida, focusing on scaling operations city by city and state by state since the initial Austin debut.
Tesla CEO Elon Musk has tempered expectations for the company’s humanoid robot Optimus, emphasizing that initial production will ramp up slowly despite recent progress on the manufacturing line. In a July 1 reply on X, Musk responded to optimistic community speculation by stating, “No, Optimus production will be extremely slow at first, as everything is new. This is not like making a car.”
No, Optimus production will be extremely slow at first, as everything is new. This is not like making a car.
— Elon Musk (@elonmusk) July 1, 2026
The comment came in response to a post theorizing that Tesla had accelerated Optimus V3 development and might soon unveil an impressive demonstration with multiple units already in meaningful production. Musk’s clarification highlights the fundamental differences between scaling a novel humanoid robot and Tesla’s established automotive operations, which benefit from over a century of refined supply chains, tooling, and processes.
Recent updates show tangible advancement. Musk shared a photo of himself walking the Optimus production line at Fremont, where Tesla is converting former Model S/X manufacturing space. According to Q1 2026 earnings commentary, limited production is slated to begin in late July or August 2026 on this converted line.
Tesla Optimus project fires up as Musk sees production line progress
Musk previously noted that Optimus features roughly 10,000 unique parts, making early output rates “literally impossible to predict” and describing them as “quite slow.” A larger dedicated factory at Giga Texas is under construction, targeting higher-volume production around summer 2027 with long-term annual capacity potentially reaching millions of units.
Some experts point out that pioneering humanoid robotics demands inventing new automation techniques, actuator supply chains, and quality-control standards in real time. Unlike vehicles, where components and assembly methods are mature, every element of Optimus—from dexterous hands to AI-integrated movement—requires fresh engineering solutions. Early units are expected to handle simple factory tasks before expanding to more complex roles.
This cautious approach aligns with Tesla’s history of under-promising and over-delivering on complex technologies. While enthusiasts hoped for rapid deployment, Musk’s message underscores a deliberate strategy: prioritize reliability and iterative improvement over rushed volume.
Analysts suggest the S-curve ramp typical of new manufacturing will eventually accelerate once foundational issues are resolved, positioning Optimus as a potential trillion-dollar product line.
Musk has long envisioned Optimus transforming labor markets, assisting in homes, factories, and hazardous environments. By setting realistic timelines, Tesla aims to build sustainable momentum rather than risk disappointment. As the Fremont line comes online this summer, investors and fans will watch closely for the first production metrics and capability demonstrations.
Tesla Semi involved in first known fatal crash in Nevada
Tesla expands Robotaxi to Florida, marking its third state for autonomy
