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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.
In a notable shift for electric vehicle perceptions, Tesla has emerged as a standout performer in the latest iSeeCars longevity study, which analyzed over 174 million used vehicles.
The data reveals that Tesla models have a 4.6 percent chance of reaching 250,000 miles, matching the industry average of 4.8 percent and tying for sixth place among 32 brands. This positions Tesla ahead of many established names, including Subaru (2.3 percent, roughly half of Tesla’s rate), Nissan (2.4 percent), Mazda, BMW, Mercedes-Benz, and Porsche.
Toyota leads with an impressive 17.8 percent likelihood, followed by Lexus (12.8 percent), Honda, and Acura. Yet Tesla’s result stands out for a relatively young EV brand. Experts attribute this to the inherent simplicity of electric powertrains: fewer moving parts mean no oil changes, timing belts, or complex engine components that typically fail in internal combustion vehicles.
Fewer things to maintain means fewer things to break, and ultimately, fewer things to go wrong.
A Tesla is twice as likely to reach 250,000 miles as a Subaru⁰⁰“No engine, no oil changes, no timing chains, no fuel injectors, and far fewer moving parts overall”⁰⁰https://t.co/k8iJwbzrrp
— Tesla North America (@tesla_na) June 8, 2026
This design advantage helps Teslas defy unfounded skepticism about battery longevity and overall durability, two things that have plagued the company from outsider perspectives without much proof.
The iSeeCars reliability ratings further bolster Tesla’s case. The Tesla Model S earns a strong 7.9/10 reliability score, ranking No. 1 out of 35 most reliable electric cars. It boasts a predicted average lifespan of about 154,419 miles (around 16.9 years) and a 21.9 percent chance of hitting 200,000 miles.
Tesla, as an electric car brand, also scores 7.9/10 overall, securing the top spot among electric vehicle manufacturers in several luxury and segment categories.
Real-world examples reinforce the data. High-mileage Teslas, including Model S vehicles exceeding one million miles, demonstrate that EVs can endure when properly maintained. Owners report minimal mechanical issues beyond typical wear items like tires and brakes, which regenerative braking often extends.
Tesla Model 3 hits quarter million miles with original battery and motor
This performance challenges narratives around EV reliability, especially amid mixed reports from other sources like Consumer Reports or regional inspections. iSeeCars‘ massive dataset emphasizes long-term durability over short-term defect rates, painting Tesla as a leader in sustainable, high-mileage ownership.
For buyers prioritizing longevity and low maintenance, Tesla’s results signal strong value. While no brand is flawless, factors like driving habits, climate, and software updates matter—the numbers suggest Tesla belongs among the elite for those seeking vehicles built to last.
As EV adoption grows, this iSeeCars data underscores Tesla’s engineering edge in creating enduring, future-proof automobiles.
Tesla owners have long griped about the wireless phone charger in the Model Y and other vehicles. It often turns smartphones into miniature ovens rather than reliably topping them up.
Software engineer and Model Y owner Michał Gapiński tackled this issue head-on with a clever DIY upgrade, swapping the cooled wireless charger pad from the China-made Model YL in for the one that came standard in his vehicle.
There are several key differences between the U.S.-built Model Y’s wireless charging pad and the one that Tesla has been installing in the Model YL. The one installed in U.S.-built vehicles lacks active cooling and relies on basic heat dissipation, leading to rapid temperature buildup during charging. In contrast, the Model YL integrates a small fan for active cooling.
Will it fit? Fingers crossed, I want a first YL charger deployed in the regular juniper pic.twitter.com/wWDqSNFVkW
— Michał Gapiński (@mikegapinski) June 2, 2026
This design maintains lower temperatures even in warm ambient conditions, though it does not support faster Qi2 charging on iPhones. The connector matches exactly, making physical swaps feasible on compatible consoles, but coding is required to enable full functionality.
Owners in the U.S. have complained about the wireless charging pad, with many reporting that overheating is fairly common. Within 20 or 30 minutes of placing a phone on the wireless charging pad, many have reported overheating messages on their phones, which halt charging and essentially turn the pad into a fancy place to rest your phone.
Many owners have opted to simply plug their phones into a charging cord. Tesla has acknowledged the problem by releasing several solutions for owners, including a relatively new feature that allows you to simply turn off the charging and simply act as a holder for your phone while driving.
Gapiński said that he sourced the cooled pad affordably from China, and it cost under $200 for the part.
He removed the existing console charger, swapped in the new unit, confirming a perfect connector fit, and handled the trim differences. Since the parameter isn’t fully secured, he enabled it through custom coding outside official Toolbox.
Connector is identical, she fits, now time to code it. https://t.co/Y9idgDrpCq pic.twitter.com/uwwgq6blg7
— Michał Gapiński (@mikegapinski) June 2, 2026
The fan activates quietly, blending with AC and seat cooling. He reported the installation was effective and the wireless charging pad worked perfectly; it even kept the phone cool as it stayed at just 86 degrees Fahrenheit. Many times, the wireless charging pad will bring the phone’s temperature well above 100 degrees, sometimes even being relatively hot to the touch.
The retrofit worked, no issues. First Model Y with a cooled wireless charger! No QI2/faster charging on the iPhone but it does not boil the phone even when it is 30 degrees outside.
The fan kicks in, it is not audible especially with the air conditioning and seat cooling. The… https://t.co/JOyR8Tb1Yo pic.twitter.com/kJcYhQIlYq
— Michał Gapiński (@mikegapinski) June 2, 2026
This retrofit highlighted an elegant, owner-driven solution to a factory shortcoming. It is expected that Tesla will begin installing the cooled charging pads into new cars in the U.S. soon, and hopefully, it will offer some sort of retrofit service or kit to owners here who want to use the charging pad effectively.
For those who love to tinker, it’s an accessible upgrade, proving that innovation thrives beyond the production line.
The Tesla Roadster unveiling could be coming “in a few weeks,” according to the company’s Chief Designer Franz von Holzhausen, who said at the Tesla Takeover Europe Event in Austria that the all-electric hypercar could finally make its way to the production line after years of anticipation.
Von Holzhausen delivered the news just days after The Information reported that Tesla planned to push the Roadster unveiling to August. It was slated for both April and May of this year, but now it seems the company is leaning toward a late Summer event to cap off the heat with perhaps its most anticipated vehicle of all-time.
🚨 Tesla Chief Designer Franz Von Holzhausen, speaking to the crowd at Tesla Takeover Europe, said at the event that the Roadster is coming “in a few weeks,”
Multiple attendees have confirmed this pic.twitter.com/B1v6yb2Geq
— TESLARATI (@Teslarati) June 6, 2026
Franz has been with Tesla since 2008, and has played a pivotal role in the iconic design language the company has utilized with its vehicles. Speaking to the crowd in Austria virtually, von Holzhausen’s comments injected fresh excitement into a project that has been plagued by delays for nine years.
The second-generation Roadster promises to redefine supercar standards. Tesla’s website still highlights ambitious targets: 0-60 mph in under 1.9 seconds (with optional SpaceX thruster pack potentially achieving 1.1 seconds or less), a top speed exceeding 250 mph, and a range of about 620 miles.
Equipped with a tri-motor all-wheel-drive setup delivering over 1,000 horsepower, the four-seater aims to blend blistering acceleration, everyday usability, and innovative features like cold gas thrusters for short-hop capabilities, technology that will combine the project with SpaceX.
But years after the company promised to start production, which was slated for 2020, the timeline for the Roadster has continued to shift.
Tesla has strung along those who have put $50,000 deposits down, as well as fans and enthusiasts of the company who have been long awaiting the company to bring forth a car truly designed for the human driver, and not autonomy. The Roadster is more than just a halo vehicle for Tesla; it showcases the company’s ability to push the boundaries while incorporating synergies from other Musk companies.
However, it has to make it to production, which is something Musk and Co. have pushed back repeatedly.
As Tesla navigates Robotaxi development and broader autonomy goals, the Roadster serves as a reminder of its performance roots. If von Holzhausen’s timeline holds, fans could witness this engineering marvel by late June or early July 2026. Whether a full unveiling, demo, or initial deliveries, it marks a milestone for electric supercars.
Tesla skeptics will hate what this new reliability study says
Tesla owner fixes common feature complaint with crafty DIY retrofit
