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.
Investor's Corner
Tesla gets bold Robotaxi prediction from Wall Street firm
Last week, Andrew Percoco took over Tesla analysis for Morgan Stanley from Adam Jonas, who covered the stock for years. Percoco seems to be less optimistic and bullish on Tesla shares, while still being fair and balanced in his analysis.
Tesla (NASDAQ: TSLA) received a bold Robotaxi prediction from Morgan Stanley, which anticipates a dramatic increase in the size of the company’s autonomous ride-hailing suite in the coming years.
Last week, Andrew Percoco took over Tesla analysis for Morgan Stanley from Adam Jonas, who covered the stock for years. Percoco seems to be less optimistic and bullish on Tesla shares, while still being fair and balanced in his analysis.
Percoco dug into the Robotaxi fleet and its expansion in the coming years in his latest note, released on Tuesday. The firm expects Tesla to increase the Robotaxi fleet size to 1,000 vehicles in 2026. However, that’s small-scale compared to what they expect from Tesla in a decade.
Tesla expands Robotaxi app access once again, this time on a global scale
By 2035, Morgan Stanley believes there will be one million Robotaxis on the road across multiple cities, a major jump and a considerable fleet size. We assume this means the fleet of vehicles Tesla will operate internally, and not including passenger-owned vehicles that could be added through software updates.
He also listed three specific catalysts that investors should pay attention to, as these will represent the company being on track to achieve its Robotaxi dreams:
- Opening Robotaxi to the public without a Safety Monitor. Timing is unclear, but it appears that Tesla is getting closer by the day.
- Improvement in safety metrics without the Safety Monitor. Tesla’s ability to improve its safety metrics as it scales miles driven without the Safety Monitor is imperative as it looks to scale in new states and cities in 2026.
- Cybercab start of production, targeted for April 2026. Tesla’s Cybercab is a purpose-built vehicle (no steering wheel or pedals, only two seats) that is expected to be produced through its state-of-the-art unboxed manufacturing process, offering further cost reductions and thus accelerating adoption over time.
Robotaxi stands to be one of Tesla’s most significant revenue contributors, especially as the company plans to continue expanding its ride-hailing service across the world in the coming years.
Its current deployment strategy is controlled and conservative to avoid any drastic and potentially program-ruining incidents.
So far, the program, which is active in Austin and the California Bay Area, has been widely successful.
News
Tesla Model Y L is gaining momentum in China’s premium segment
This suggests that the addition of the Model Y L to Tesla China’s lineup will not result in a case of cannibalization, but a possible case of “premiumization” instead.
Tesla’s domestic sales in China held steady in November with around 73,000 units delivered, but a closer look at the Model Y L’s numbers hints at an emerging shift towards pricier variants that could very well be boosting average selling prices and margins.
This suggests that the addition of the Model Y L to Tesla China’s lineup will not result in a case of cannibalization, but a possible case of “premiumization” instead.
Tesla China’s November domestic numbers
Data from the a Passenger Car Association (CPCA) indicated that Tesla China saw domestic deliveries of about 73,000 vehicles in November 2025. This number included 34,000 standard Model Y units, 26,000 Model 3 units, and 13,000 Model Y L units, as per industry watchers.
This means that the Model Y L accounted for roughly 27% of Tesla China’s total Model Y sales, despite the variant carrying a ~28% premium over the base RWD Model Y that is estimated to have dominated last year’s mix.
As per industry watcher @TSLAFanMtl, this suggests that Tesla China’s sales have moved towards more premium variants this year. Thus, direct year-over-year sales comparisons might miss the bigger picture. This is true even for the regular Model Y, as another premium trim, the Long Range RWD variant, was also added to the lineup this 2025.
November 2025 momentum
While Tesla China’s overall sales this year have seen challenges, the Model Y and Model 3 have remained strong sellers in the country. This is especially impressive as the Model Y and Model 3 are premium-priced vehicles, and they compete in the world’s most competitive electric vehicle market. Tesla China is also yet to roll out the latest capabilities of FSD in China, which means that its vehicles in the country could not tap into their latest capabilities yet.
Aggregated results from November suggest that the Tesla Model Y took the crown as China’s #1 best-selling SUV during the month, with roughly 34,000 deliveries. With the Model Y L, this number is even higher. The Tesla Model 3 also had a stellar month, seeing 25,700 deliveries during November 2025.
Cybertruck
Tesla Cybertruck earns IIHS Top Safety Pick+ award
To commemorate the accolade, the official Cybertruck account celebrated the milestone on X.
The Tesla Cybertruck has achieved the Insurance Institute for Highway Safety’s (IIHS) highest honor, earning a Top Safety Pick+ rating for 2025 models built after April 2025.
The full-size electric pickup truck’s safety rating is partly due to the vehicle’s strong performance in updated crash tests, superior front crash prevention, and effective headlights, among other factors. To commemorate the accolade, the official Cybertruck account celebrated the milestone on X.
Cybertruck’s IIHS rating
As per the IIHS, beginning with 2025 Cybertruck models built after April 2025, changes were made to the front underbody structure and footwell to improve occupant safety in driver-side and passenger-side small overlap front crashes. The moderate overlap front test earned a good rating, and the updated side impact test also received stellar marks.
The Cybertruck’s front crash prevention earned a good rating in pedestrian scenarios, with the standard Collision Avoidance Assist avoiding collisions in day and night tests across child, adult crossing, and parallel paths. Headlights with high-beam assist compensated for limitations, contributing to the top award.
Safest and most autonomous pickup
The Cybertruck is one of only two full-size pickups to receive the IIHS’ Top Safety Pick + rating. It is also the only one equipped with advanced self-driving features via Tesla’s Full Self-Driving (Supervised) system. Thanks to FSD, the Cybertruck can navigate inner city streets and highways on its own with minimal supervision, adding a layer of safety beyond passive crash protection.
Community reactions poured in, with users praising the vehicle’s safety rating amidst skepticism from critics. Tesla itself highlighted this by starting its X post with a short clip of a Cybertruck critic who predicted that the vehicle will likely not pass safety tests. The only question now is, of course, if the vehicle’s Top Safety Pick+ rating from the IIHS will help the Cybertruck improve its sales.
Tesla gets bold Robotaxi prediction from Wall Street firm
Tesla Model Y L is gaining momentum in China’s premium segment
