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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 Cybercab tests are going on overdrive with production-ready units
Tesla is ramping its real-world tests of the Cybercab, with multiple sightings of the vehicle being reported across social media this week.
Tesla is ramping its real-world tests of the Cybercab, with multiple sightings of the autonomous two-seater being reported across social media this week. Based on videos of the vehicle that have been shared online, it appears that Cybercab tests are underway across multiple states.
Recent Cybercab sightings
Reports of Cybercab tests have ramped this week, with a vehicle that looked like a production-ready prototype being spotted at Apple’s Visitor Center in California. The vehicle in this sighting was interesting as it was equipped with a steering wheel. The vehicle also featured some changes to the design of its brake lights.
The Cybercab was also filmed testing at the Fremont factory’s test track, which also seemed to involve a vehicle that looked production-ready. This also seemed to be the case for a Cybercab that was spotted in Austin, Texas, which happened to be undergoing real-world tests. Overall, these sightings suggest that Cybercab testing is fully underway, and the vehicle is really moving towards production.
Production design all but finalized?
Recently, a near-production-ready Cybercab was showcased at Tesla’s Santana Row showroom in San Jose. The vehicle was equipped with frameless windows, dual windshield wipers, powered butterfly door struts, an extended front splitter, an updated lightbar, new wheel covers, and a license plate bracket. Interior updates include redesigned dash/door panels, refined seats with center cupholders, updated carpet, and what appeared to be improved legroom.
There seems to be a pretty good chance that the Cybercab’s design has been all but finalized, at least considering Elon Musk’s comments at the 2025 Annual Shareholder Meeting. During the event, Musk confirmed that the vehicle will enter production around April 2026, and its production targets will be quite ambitious.
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Tesla gets a win in Sweden as union withdraws potentially “illegal” blockade
As per recent reports, the Vision union’s planned anti-Tesla action might have been illegal.
Swedish union Vision has withdrawn its sympathy blockade against Tesla’s planned service center and showroom in Kalmar. As per recent reports, the Vision union’s planned anti-Tesla action might have been illegal.
Vision’s decision to pull the blockade
Vision announced the blockade in early December, stating that it was targeting the administrative handling of Tesla’s facility permits in Kalmar municipality. The sympathy measure was expected to start Monday, but was formally withdrawn via documents sent to the Mediation Institute and Kalmar Municipality last week.
As noted in a Daggers Arbete report, plans for the strike were ultimately pulled after employer group SKR highlighted potential illegality under the Public Employment Act. Vision stressed its continued backing for the Swedish labor model, though Deputy negotiation manager Oskar Pettersson explained that the Vision union and IF Metall made the decision to cancel the planned strike together.
“We will not continue to challenge the regulations,” Petterson said. “The objection was of a technical nature. We made the assessment together with IF Metall that we were not in a position to challenge the legal assessment of whether we could take this particular action against Tesla. Therefore, we chose to revoke the notice itself.”
The SKR’s warning
Petterson also stated that SKR’s technical objection to the Vision union’s planned anti-Tesla strike framed the protest as an unauthorized act. “It was a legal assessment of the situation. Both for us and for IF Metall, it is important to be clear that we stand for the Swedish model. But we should not continue to challenge the regulations and risk getting judgments that lead nowhere in the application of the regulations,” he said.
Vision ultimately canceled its planned blockade against Tesla on December 9. With Vision’s withdrawal, few obstacles remain for Tesla’s long-planned Kalmar site. A foreign electrical firm completed work this fall, and Tesla’s Careers page currently lists a full-time service manager position based there, signaling an imminent opening.
Tesla Semi Program Director Dan Priestly teased the major improvements to the all-electric Class 8 truck on Thursday night, following the company’s decision to overhaul the design earlier this year.
Priestley said he drove the Semi on Thursday, and the improvements appear to be welcomed by one of the minds behind the project. “Our customers are going to love it,” he concluded.
Just drove the redesigned Semi. Our customers are going to love it. https://t.co/KZ88sf1CDL
— Dan Priestley (@danWpriestley) December 19, 2025
The small detail does not seem like much, but it is coming from someone who has been involved in the development of the truck from A to Z. Priestley has been involved in the Semi program since November 2015 and has slowly worked his way through the ranks, and currently stands as the Director of the program.
Tesla Semi undergoes major redesign as dedicated factory preps for deliveries
Tesla made some major changes to the Semi design as it announced at the 2025 Annual Shareholder Meeting that it changed the look and design to welcome improvements in efficiency.
Initially, Tesla adopted the blade-like light bar for the Semi, similar to the one that is present on the Model Y Premium and the Cybertruck.
Additionally, there are some slight aesthetic changes to help with efficiency, including a redesigned bumper with improved aero channels, a smaller wraparound windshield, and a smoother roofline for better aero performance.
All of these changes came as the company’s Semi Factory, which is located on Gigafactory Nevada’s property, was finishing up construction in preparation for initial production phases, as Tesla is planning to ramp up manufacturing next year. CEO Elon Musk has said the Semi has attracted “ridiculous demand.”
The Semi has already gathered many large companies that have signed up to buy units, including Frito-Lay and PepsiCo., which have been helping Tesla test the vehicle in a pilot program to test range, efficiency, and other important metrics that will be a major selling point.
Tesla will be the Semi’s first user, though, and the truck will help solve some of the company’s logistics needs in the coming years.
Tesla Cybercab tests are going on overdrive with production-ready units
Tesla gets a win in Sweden as union withdraws potentially “illegal” blockade
