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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.
Tesla Cybercab units finally got a definitive date for when they will be able to be purchased by consumers, ending speculation regarding whether the fully autonomous vehicle would be available in the near term.
During Tesla’s third-quarter 2026 earnings call on October 21, Vice President of Engineering Lars Moravy said the company is aiming to begin delivering its purpose-built Cybercab robotaxi to customers before year-end.
🚨 In short, Cybercabs are slated to go to customers by end of the year. All units are going into Robotaxi fleet currently, per @larsmoravy
Cybercab will be “transport-as-a-service,” but vast majority of Cybercab will be “Tesla-owned,” @elonmusk says https://t.co/R8Qu8QWdmp
— TESLARATI (@Teslarati) October 21, 2026
“We’re trying to get Cybercabs to customers by the end of this year, 2026,” Moravy said. He added that production is underway on the line at Gigafactory Texas, but “all of those are currently going to our own internal Robotaxi fleet.”
Moravy explained that as operations scale, Tesla will “mainly deliver fully designed autonomous vehicles to our customers,” with the Cybercab as the first such vehicle. Initial customer deliveries will start small while the company gains experience with delivery logistics, ownership models, fleet management, and operating autonomous vehicles outside its direct control.
CEO Elon Musk reinforced the limited nature of private sales, describing the Cybercab primarily as a “transport-as-a-service” offering rather than a personal ownership vehicle like the Model 3, Model Y, or upcoming Roadster. “The vast majority of the Cybercab stuff will be Tesla-owned and transport-as-a-service,” Musk said.
The Cybercab is a two-seater vehicle developed by Tesla without a steering wheel or pedals. It relies completely on Tesla’s Full Self-Driving suite and has been in production since February. Early units have been put in Tesla’s Robotaxi service as of early September, when the company launched rides to the public. Tesla previously indicated it would aim to sell Cybercabs for about $30,000.
Unsupervised Full Self-Driving is expected to ship to consumer cars during Q2 2027, Ashok Elluswamy, Tesla’s Head of AI, indicated during the call. Early buyers or fleet operators may receive vehicles whose autonomous operation remains geographically restricted due to lagging regulatory agencies. There are some hurdles that remain ahead of Cybercab deliveries.
Tesla (NASDAQ: TSLA) reported its earnings for the third quarter of 2026, marking a reasonable performance on the various financial metrics. Tesla still plans to hold a call that will field investor questions at 5:30 p.m. ET, 4:30 p.m. CT.
Here’s where Earnings came in:
- Total Revenues: $28.046 reported vs. $28.34B expected
- Non-GAAP EPS: $0.48 reported vs. $0.45 expected
- Operating Margin: 2.6 % reported vs. 2.5% expected
- Operating Income: $718M reported vs. $721M expected
- Free Cash Flow: $1.531B reported vs. ~-$4.51B expected
Tesla $TSLA Earnings Results:
Revenues: $28.046B
Non-GAAP EPS: $0.48
Operating Margin: 2.6%
Operating Income: $718M
FCF: $1.531B— TESLARATI (@Teslarati) October 21, 2026
Major Takeaways
Full Self-Driving (Supervised)
“FSD (Supervised)⁴ attach rate continued to grow, reaching over 75% of new vehicle deliveries in North America – our most mature market – a nearly twenty percentage point sequential increase. We believe that FSD is driving demand in markets where it is available, and we continue to work with regulators to get it approved in other markets.”
Tesla Semi
“We began volume production of Tesla Semi, our Class 8 heavy-duty truck. The top variant can go 500 miles at full 82,000 lbs gross combination weight while achieving an efficiency of 1.7 kWh/mile. That efficiency allows the Tesla Semi to use a third of the energy used by a comparable diesel truck to haul the same payload. In a transportation market where energy is one of the largest components of total cost per mile, this will provide a meaningful advantage to Tesla Semi operators.”
SI Compute
“We plan to reach 400 MW of SI training compute by the end of the year, supporting the development of both vehicle and humanoid robot autonomy software. Additionally, we continued construction for the Austin Fab, where we plan to start commissioning equipment in 2027.”
Robotaxi
“We began deployment of Cybercab into our Robotaxi fleet in Austin. We reached nearly two million cumulative unsupervised miles for our Robotaxi service as of the end of the quarter. Operating hours in Austin are now 6am to midnight, and we expect to reduce wait times via increased fleet supply and improvement of Robotaxi orchestration algorithms. Grok is available in Cybercab with access to Grok Bot and Connectors, which allows users to manage their inbox, calendars, files, chats and tasks – all hands free via voice command – making Cybercab a mode of transport, a productivity space and, with our entertainment options, a second living room.”
Interested in ordering a Tesla? Use my referral code for three free months of Full Self-Driving (Supervised) here.
Tesla (NASDAQ: TSLA) reports its earnings for Q3 today. Here’s what to expect, as the company will reveal its balance sheet after the market closes on Wednesday.
Tesla already reported deliveries just after Q3 ended, and it demolished Wall Street consensus estimates of roughly 462,000 vehicles. Tesla delivered 486,532 cars in the third quarter, which was a big beat, but was down 2.1 percent from the same quarter last year. Energy storage deployments were 13.7 GWh, up year-over-year.
Tesla showrooms picked clean ahead of Q3 end as demand looks strong
For the quarter, analysts have already compiled their predictions for what Tesla will report this afternoon:
- Total Revenues: $28.34B
- Non-GAAP EPS: $0.43
- Operating Margin: 2.5%
- Operating Income: $721M
- Free Cash Flow: ~-$4.51B
Here are a few things we are looking forward to hearing about on the call:
Automotive Gross Margin and Overall Profitability
This was 16.3 percent in Q2, down from 19.2 percent in Q1, and was impacted by warranty charges and some fading regulatory credits. Consensus implies overall gross margin near 18 percent, but a miss here would potentially reinforce concerns about pricing pressure on its vehicles.
Pay attention to energy storage margins as well, especially since Tesla missed GWh expectations, although it was still a strong quarter.
Robotaxi/Cybercab, Unsupervised FSD, and Optimus Progress
The Say questions from retail investors usually focus on these types of projects, and this quarter is no different. Scaling the Cybercab fleet beyond Austin amid the open NHTSA safety review, timeline for Unsupervised FSD in customer cars, Robotaxi unit economics, and Optimus cost per unit plus when it could start generating revenue, are all things to be looking for.
Any concrete timelines or regulatory path details will likely move the stock more than the near-term numbers. SpaceX merger speculation, which was detailed during SpaceX’s earnings call last night, may also surface, although the key details were shared last night.
Elon Musk just confirmed the Tesla and SpaceX merger step everyone was waiting for
Say Investor Questions
- How does the Cybercab fleet scale past Austin, and what’s the regulatory path outside Texas given NHTSA’s open safety review?
- When can we anticipate FSD unsupervised in customer cars?
- When will the CyberCab be available for customer purchase/ownership?
- What’s the unit economics per paid robotaxi mile, and how does it compare to the thirty-cent target?
- Tesla has acknowledged that HW3 vehicles cannot support unsupervised FSD. When will owners know whether they can upgrade their hardware for free, and when will Tesla provide a clear plan?
The full Earnings Call will be streamed this evening after market close around 5 p.m. this evening.
Tesla Cybercab gets a for sale date at last
Tesla Q3 2026 Earnings results: in-line revenues, slight beat on EPS
