Connect with us

News

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

Published

9 years ago

on

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:

Advertisement

“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.

Advertisement

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.

Advertisement
Related Topics:
Advertisement
Comments

Cybertruck

Tesla clears the air on Cybertruck ‘deactivation’ video that is obviously fake

Tesla has cleared the air on the viral video, stating it is fake.

Published

7 hours ago

on

August 11, 2025

By

Credit: Cybertruck | X

Tesla has cleared the air regarding a video that has been circulating, where the owner claims his Cybertruck was “deactivated” by the company while he was driving.

The video was shared on X and showed a driver pulled over on the side of the road, claiming his Cybertruck had been deactivated by Tesla in the middle of traffic. It is very obviously fake to those who know the company, but these kinds of things have a tendency to pick up steam.

Advertisement

The video shows a screen that says:

“Tesla Cybertruck De-Activated. Critical Issue Detected | Contact Customer Service, Comply with Cease & Desist to Re-Activate. Update Failed, Return to Dealer.”

The same person who posted the video also shared an image of what appears to be a Cease and Desist letter from Tesla, but it is also likely fake:

The company finally responded to the video on Monday afternoon, stating that the video is, in fact, fake, reiterating that it will not disable vehicles remotely for any reason.

Advertisement

It is a shame that these types of things happen, especially as people are prone to believe anything they see on the internet. As there is so much misinformation circulating surrounding Tesla and its CEO Elon Musk, it is no surprise that someone would leverage the situation for their own benefit.

If that Cease and Desist letter is not real, perhaps the next one might be. These types of things can truly cause damage to a company’s reputation, and someone getting an idea that Tesla would remotely deactivate a car could prevent them from buying one.

Continue Reading

Elon Musk

Elon Musk is stepping up for Tesla Service in a big way

Elon Musk has stepped up to resolve a handful of customer issues regarding vehicle service.

Published

8 hours ago

on

August 11, 2025

By

tesla service
Credit: Tesla

Elon Musk is stepping up to help customers in a big way, especially when they are having issues with Tesla’s Service.

Perhaps one of the biggest advantages Tesla owners have is access to Musk through X, his social media platform. Over the years, we’ve seen Tesla add features, refine its cars’ performance, and more, all through asking Musk directly through a post.

Now, Musk is stepping up in another way by resolving a few Service complaints that customers had.

The first occurred last week when a recall on a Tesla battery was not honored by Service. The company sought $30,000 for a replacement and labor, which was not right. Musk responded that he would personally investigate the matter. The vehicle was fixed at no cost as it was a recall, and was ready for pickup the next day.

It also revealed a new strategy Tesla is using to combat service communication issues:

Tesla creates clever solution to simplify and improve its Service

The next occurred with a Cybertruck owner who was in Japan. Their car was parked at an airport in the U.S. and had lost a vast majority of its state of charge, leaving them just fifty miles of range at the time.

Advertisement

Musk reached out to the owner and said Service will take care of the car and will investigate the cause of the battery drain:

There are not too many companies out there where the CEO will get involved with individual issues like these. It’s pretty exclusive to Tesla, as Musk has commonly stepped up to resolve complaints with vehicles or to confront features that some owners might find useful.

Service has been a weak point of the company for some time, but it has worked to refine and resolve customer complaints by building more Service Centers across the world that can handle these issues.

Advertisement
Continue Reading

Elon Musk

Tesla CEO Elon Musk confirms Robotaxi is opening to the public: here’s when

Anyone will be able to request a Tesla Robotaxi in September, Elon Musk said this morning.

Published

10 hours ago

on

August 11, 2025

By

Credit: Joe Tegtmeyer | X

Tesla CEO Elon Musk has confirmed that the company’s Robotaxi platform is opening to the public, and he even gave a timeline for when anyone will be able to access one for a ride.

Tesla’s Robotaxi platform launched to a small group on June 22 in Austin, Texas. The company has continued to expand the number of riders and its geofence over the past month and a half.

Tesla officially launches Robotaxi service with no driver

Additionally, it launched rides in the Bay Area of California, but it differs slightly, as the Texas Robotaxi platform does not utilize a Safety Monitor in the driver’s seat. In California, the monitor sits in the driver’s seat.

As the geofence, service areas, and testing populations expand, Tesla fans are awaiting their elusive emails that enable their ability to use the Robotaxi platform. It now seems that the email will come soon, as Musk said Tesla will open up public access to Robotaxi next month:

Advertisement

Tesla has been prioritizing safety over anything else with the launch of the Robotaxi platform, which is why it has been slow to push invitations to new riders. It is confident in the abilities of the platform and its Full Self-Driving suite, which has been proven with data.

However, even a single accident could set Tesla back years in terms of its development of self-driving cars. It is not a risk it is willing to take.

Musk said during the recent Q2 Earnings Call:

Advertisement

“We need to make sure it works when the vehicles are fully under our control. It’s kind of one step at a time here. We don’t want to jump the gun. As I said, we’re being paranoid about safety. But I guess next year is I’d say confidently next year. I’m not sure when next year, but confidently next year, people would be able to add or subtract their car to the Tesla, Inc. fleet.”

As the platform will expand in Austin and the Bay Area for anyone, Tesla still continues to reiterate that Robotaxi will be available for everyone sometime next year, as Musk said in the quote above.

Things will continue to improve over time, and Tesla will likely expand its geofence in both regions in the coming weeks. It has already done that in Austin twice, with about a doubling in size occurring both times.

Continue Reading

Trending