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Why Tesla’s lead acid 12V battery needs to be lithium-ion based

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9 years ago

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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:

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“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.

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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 adjusts Robotaxi safety monitor strategy in Austin with new service area

The positioning of the driver, as well as the driver’s hands being closer to the steering wheel, is more similar to what Tesla is doing in the Bay Area Robotaxi program than it is to what it has done in Austin.

Published

11 hours ago

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September 2, 2025

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Credit: @AdanGuajardo/X

Tesla has adjusted its Robotaxi safety monitor strategy in Austin after it expanded its service area in the city last week for the third time.

Tesla has been operating its Robotaxi platform in Austin since June 22. The vehicles have been operated without a driver, but Tesla has placed safety monitors in the passenger’s seat as a precaution.

The safety monitors are responsible for performing any necessary interventions and maintaining a safe and comfortable cabin for riders as they experience Tesla’s first venture into the driverless ride-sharing space.

Last week, Tesla expanded its service area in Austin for the third time, expanding it from about 90 square miles to 170 square miles. The expansion included new territory, including the Austin-Bergstrom International Airport, Tesla’s Gigafactory Texas, and several freeways.

Tesla Robotaxi geofence expansion enters Plaid Mode and includes a surprise

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The freeway is an area that is uncharted territory for the Tesla Robotaxi program, and this fact alone encouraged Tesla to switch up its safety monitor positioning for the time being.

For now, they will be riding in the driver’s seat when routes require freeway travel:

The positioning of the driver, as well as the driver’s hands being closer to the steering wheel, is more similar to what Tesla is doing in the Bay Area Robotaxi program than it is to what it has done in Austin.

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This is sure to draw criticism from skeptics, but it is simply a step to keep things controlled and safe while the first Robotaxi drives take passengers on the highway with this version of the Full Self-Driving software.

This FSD version differs from the one that customers have in their own vehicles, but CEO Elon Musk has indicated something big is coming soon. FSD v14 is coming to vehicles in the near future, and Musk has said its performance is pretty incredible.

Tesla’s Elon Musk shares optimistic teaser about FSD V14: “Feels sentient”

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Tesla has best month ever in Turkey with drastic spike in sales

Tesla managed to sell 8,730 Model Y vehicles in Turkey, outpacing almost every competitor by a substantial margin. Only one brand sold better than Tesla in August in Turkey, and it was Renault.

Published

12 hours ago

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September 2, 2025

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Credit: Tesla

Tesla had its best monthly performance ever in Turkey in August, thanks to a drastic spike in sales.

Tesla saw an 86 percent bump in sales of the new Model Y in Turkey in August compared to July, dominating the market.

The performance was one of Tesla’s best in the market, and the company’s sales for the month accounted for half of all EV sales in Turkey for August, as it dominated and led BYD, which was the second-best-selling brand with just 1,639 units sold.

Tesla managed to sell 8,730 Model Y vehicles in Turkey, outpacing almost every competitor by a substantial margin. Only one brand sold better than Tesla in August in Turkey, and it was Renault.

Electric vehicles are, in some ways, more desirable than their gas counterparts in Turkey for several reasons. Most of the reasoning is financial.

First, EVs are subject to a lower Special Consumption Tax in Turkey. EVs can range from 25 percent to up to 170 percent, but this is less than the 70 to 220 percent rate that gas-powered vehicles can face. The tax is dependent on engine size.

Elon Musk courted to build a Tesla factory in Turkey

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Additionally, EVs are exempt from the annual Motor Vehicle Tax for the first ten years, providing consumers with a long-term ownership advantage. There are also credits that can amount to $30,000 in breaks, which makes them more accessible and brings down the cost of ownership.

Let’s not forget the other advantages that are felt regardless of country: cheaper fuel costs, reduced maintenance, and improved performance.

The base Model Y is the only configuration available in Turkey currently.

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Tesla is upgrading airbag safety through a crazy software update

“This upgrade builds upon your vehicle’s superior crash protection by now using Tesla Vision to help offer some of the most cutting-edge airbag performance in the event of a frontal crash.”

Published

15 hours ago

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September 2, 2025

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(Credit: Tesla)

Tesla is upgrading airbag safety through a crazy software update, which will utilize the company’s vision-first approach to enable better protection in the event of an accident.

Over the years, Tesla has gained an incredible reputation for prioritizing safety in its vehicles, with crash test ratings at the forefront of its engineers’ minds.

This has led to Tesla gaining numerous five-star safety ratings and awards related to safety. It is not just a statistical thing, either. In the real world, we’ve seen Teslas demonstrate some impressive examples of crash safety.

Everything from that glass roof not caving in when a tree falls on it to a Model Y surviving a drive off a cliff has been recorded.

However, Tesla is always looking to improve safety, and unlike most companies, it does not need a physical hardware update to do so. It can enhance features such as crash response and airbag performance through Over-the-Air software updates, which download automatically to the vehicle.

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In Tesla’s 2025.32 Software Update, the company is rolling out a Frontal Airbag System Enhancement, which aims to use Tesla Vision, the company’s camera-based approach to self-driving, to keep occupants safe.

The release notes state (via NotaTeslaApp):

“This upgrade builds upon your vehicle’s superior crash protection by now using Tesla Vision to help offer some of the most cutting-edge airbag performance in the event of a frontal crash. Building on top of regulatory and industry crash testing, this release enables front airbags to begin to inflate and restrain occupants earlier, in a way that only Tesla’s integrated systems are capable of doing, making your car safer over time.”

The use of cameras to predict a better time to restrain occupants with seatbelts and inflate airbags prior to a collision is a fantastic way to prevent injuries and limit harm done to those in the vehicle.

The feature is currently limited to the Model Y.

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