Study finds that using Superchargers frequently doesn't cause a significant difference on battery life
Recurrent
It has long been believed in the industry that frequent DC fast charging for your Tesla or any EV is terrible for battery longevity. However, a new report from Recurrent, which analyzed data from over 12,500 Tesla vehicles in the US, clearly shows little to no difference in battery degradation between frequent and rare fast charging.
Recurrent studied fast charging on thousands of Tesla vehicles in the US to learn if the software and safety mechanisms in the battery management system (BMS) prevent damage to the battery. With Labor Day travel coming up, this is the perfect time to share what is fact and fiction when it comes to fast charging.
The Recurrent Study: A Comprehensive Analysis
Your electric vehicle battery uses direct current (DC) power. However, the electricity from the grid (or from an outlet) is alternating current (AC). In-home charging, which is AC charging, the car’s onboard charger converts the AC electricity to DC and then sends it to the battery. The onboard charger has a built-in limit on how quickly it can do this. The maximum speed is usually around 11 kW, so AC charging can generally add 20-40 miles per hour, depending on the vehicle.
On the other hand, DC charging happens when the conversion to DC energy happens outside of the car. This is almost exclusively reserved for public charging stations and Tesla Superchargers. Since the electricity going into the car bypasses the onboard converter, it can refill the battery much faster. One of the biggest concerns with fast charging is that it can, theoretically, damage the battery by pushing too much energy into the battery too quickly. This would lead to irreparable, long-term range loss.
Key Findings: No Significant Impact on Battery Degradation
Will fast charging hurt my EV battery? The short answer is that occasional fast charging is fine. The study compared cars that fast charge at least 90% of the time to cars that fast charge less than 10% of the time. In other words, people who almost exclusively fast charge their car and people who rarely fast charge.
The results show no statistically significant difference in range degradation between Teslas that fast charge more than 90% of the time and those that fast charge less than 10% of the time.
Initial analysis by the team at Recurrent suggests that the study findings can be applied across Tesla models and other EV manufacturers. However, detailed research is being conducted on other popular vehicles Recurrent supports. In short, the robust thermal, voltage, and battery management systems that EV makers have invested in protect their batteries from damage with routine fast charger use.
Tesla specifically does an excellent job regulating power to and from the battery based on the temperature of the battery pack, its state of charge (charge percentage), and other environmental factors such as external temperature.
When Fast Charging Can Cause Damage
When is fast charging more likely to cause damage? There are several times when fast charging may impact your EV battery more. Avoid fast charging in extreme heat without preconditioning your battery. Preconditioning is when the car’s thermal management system pre-cools or heats the battery to accept a higher charge rate.
Typically, the battery will be preconditioned if you set your car’s navigation to a fast charge station. Similarly, precondition the battery before fast charging in extreme cold. Driving a bit before fast charging is often enough to warm up the battery or get to the fast charger using your car’s navigation. Avoid fast charging your EV at very low states or very high states of charge since battery resistance will be higher.
Overall, this study adds to the growing body of knowledge regarding EV battery longevity and charging practices. Nonetheless, being mindful of battery health during extreme temperatures is still encouraged.
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While most automakers are adding basic and un-integrated AI assistants to their vehicles, Tesla appears to be working hand-in-hand with xAI to build out an entire cast of characters for in-vehicle Grok. In the latest dive into Tesla’s firmware, Tesla hacker @greentheonly uncovered a few new details about the upcoming Grok feature.
This discovery, part of a larger batch of changes found in Tesla update 2025.20, also offers a hint at the hardware required for Grok.
A Dozen Groks
While we knew from previous firmware teardowns that Tesla was adding various Grok personalities to the vehicle UI, this update introduces a new one called Language Tutor, which may allow users to learn and practice a new language.
These are the different personas that will be included in Grok:
Argumentative
Assistant
Conspiracy
Doctor
Kids’ Stories
Kids’ Trivia Games
Meditation
Motivation
Romantic
Sexy
Storyteller
Therapist
Language Tutor
and the Grok Classic - Unhinged Mode
Release Date
Icons for these personalities have been added to the firmware for the first time, leading us to think Tesla is getting close to releasing the feature. However, even after the feature is developed and included in vehicle software, Tesla may only enable it selectively — such as for select employees for testing.
Grok is expected to be one of the largest vehicle features added via a software update, so it’ll be a big deal when it’s finally released. While we know more or less what to expect from Grok, what we don’t know is about vehicle requirements or whether it’ll require a subscription beyond Premium Connectivity.
Grok Requirements
While subscriptions required are anyone’s guess, vehicle requirements may be a little clearer now, thanks to Green’s discovery that Grok is only being added to AMD-based vehicle software builds.
Unfortunately, this likely means that older, Intel-based vehicles will not receive Grok support, at least for the time being. When Tesla introduced a voice assistant in China, they also started off with AMD-only support but later added Intel support, so it’s possible that the same could happen with Grok.
Energy Saving
Green also found a new undocumented navigation feature in 2025.20.3. This one focuses on leveraging Tesla’s vast amounts of data in an interesting way and offers drivers proactive advice to save energy on a well-traveled route.
In the Energy App, your vehicle will display, “This route is typically driven at X mph. Slow down by Y mph to save Z% for the rest of this trip.’
As you can see in the photo below, Tesla recognizes that vehicles typically drive at 66 mph on the route being driven and offers the driver the option to go five mph slower to save 1% of range. While this example doesn’t provide much incentive to slow down, it could be useful for someone with a low state of charge or if the savings are more significant.
In the future, Tesla could even use this, alongside the road surface data they’re gathering, to help plan routes for Robotaxi and Unsupervised FSD.
In a letter to industry, the National Highway Traffic Safety Administration (NHTSA) has announced that it is overhauling its approvals process for vehicles designed without human controls.
The change addresses a regulatory bottleneck that has slowed down American companies like Tesla from deploying purpose-built Robotaxis, rather than relying on using traditional vehicles with steering wheels and pedals. The policy shift is outlined in a letter posted to the NHTSA’s website, which you can find here.
Reducing Approvals From Years to Months
Under the existing rules today, any vehicle that is built without a steering wheel or brake pedals must receive a special exemption from federal safety standards.
Obtaining exemptions for a particular vehicle was a time-consuming process for both the companies requesting exemptions and the NHTSA. The process was often a black box—nobody knew when an exemption might be granted, and approvals could take years.
The NHTSA, under the new administration’s guidelines for autonomous vehicle development, is now committed to streamlining this process. The agency will be implementing a new, faster approach immediately for receiving exemptions for autonomous vehicles without standard controls. The NHTSA expects decisions on exemption requests to be determined within months rather than years.
Accelerating the Cybercab
This change has massive implications for Tesla, which is banking on the production of the simplified and easy-to-maintain purpose-built Cybercab. The Cybercab is developed from the ground up as an autonomous Robotaxi and will be one of the key beneficiaries of this move by the NHTSA.
Knowing that a final design won't be caught in a multi-year regulatory limbo provides a level of certainty that has been missing. It allows Tesla to confidently plan the manufacturing, development, and deployment processes without worrying whether the project will get stuck in regulatory approvals.
According to the letter, the agency will publish its improved instructions for the streamlined process "shortly." With Tesla already having begun Cybercab pre-production and the goals for its deployment as soon as late 2026, there’s still a lot to be done to make autonomy a part of Tesla’s new sustainable abundance mission statement.