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Tesla can solve an annoying part of its cars’ ownership experience with Maxwell’s supercapacitors
When Tesla acquired Maxwell technologies, the electric vehicle community was appropriately excited. Maxwell, after all, works on projects such as dry battery electrode tech and supercapacitors, both of which are believed to hold a lot of potential in the emerging electric vehicle sector. But as the countdown to the highly-anticipated Battery Day draws near, speculations suggest that Tesla acquired Maxwell mainly due to the company’s dry battery electrode tech, not its supercapacitors. Yet according to Andrey Shigaev, CEO of Geyser Batteries, supercapacitors still hold some potential uses for Tesla’s electric cars.
In a brief interview with Teslarati, Shigaev, whose company is developing batteries that use aqueous (water-based) electrolytes, noted that while supercapacitors will likely not be involved in Tesla’s million-mile battery project, there are already a lot of local tasks in an electric vehicle that could benefit from the use of supercapacitors. Among these is smart air suspension, a feature that is currently used in the Model S and X and is expected for upcoming vehicles like the Cybertruck. But beyond this, the Geyser Batteries CEO mentioned that supercapacitors could also be utilized as a superior alternative to the 12V battery that Tesla uses for its vehicles today.
“The more stuff gets electrified, the more power you need to perform tasks. The most classical thing (that could benefit from supercapacitors) and the number one item for Tesla is the 12V battery. Supercapacitors can handle this task. If you have a high energy battery onboard, then this secondary circuit could be powered by a supercapacitor that is very efficient. It will even have an extremely long life cycle. Supercapacitors are lighter too, saving weight. And they tend to be smaller than a lead-acid battery,” Shigaev said.
Interestingly enough, the earliest versions of the original Tesla Roadster didn’t use a 12V battery. Instead, the company used a portion of the Roadster’s main lithium-ion battery pack to supply 12V for the vehicles’ accessories and lights. This did not prove ideal, however, and in 2010, Tesla switched to using a 12V battery for the Roadster 2.0. It should be noted that the 12V battery, which has been adopted in every vehicle since the Roadster 2.0, is used to keep systems such as emergency blinkers, airbags, seatbelt pre-tensioners, the MCU, and other functions operational even when a car’s main battery pack is compromised.
Being one of the few parts of the car that is still based on conventional automotive tech, the 12V battery in a Tesla tends to last only a few years. As noted by Tesla Tap, the 12V battery in a brand new Tesla could last about 3-4 years, but this could be reduced to as little as 1-2 years if the vehicle is driven frequently. This could cause annoyances among Tesla owners, especially since the 12V battery’s health could not be actively observed in the vehicle’s systems yet. Social media posts about 12V batteries in Teslas giving out are numerous, with some owners noting that it is the one aspect of the Tesla ownership experience that is still mildly infuriating.
With this in mind, the use of supercapacitors in place of the 12V battery could be pretty in-character for Tesla. Nevertheless, the Geyser CEO explained that using supercapacitors in place of the 12V battery would present some challenges as well. Among these is cost, since supercapacitors are notably more expensive than standard 12V lead-acid batteries. Yet despite this, the advantages they bring could justify their use, especially among flagship vehicles like the next-generation Roadster and the Plaid Model S and Model X.
“Supercapacitors have a main caveat. There are three drawbacks. First and foremost is energy density, which is ten times lower than lead-acid battery. Second is their price since currently, their price is astronomically larger. The third is discharge. If you leave it alone for almost one month, it would discharge completely. However, if you have an electric car and there’s a high energy battery in the car like a lithium-ion battery, that would be the power source for the vehicle,” Shigaev noted.
Other industry experts have suggested uses for Maxwell’s supercapacitors in Tesla’s electric cars in the past. Auto veteran and Munro & Associates Sr. Associate Mark Ellis previously noted that apart from dry electrode tech, Tesla could tap into Maxwell’s supercapacitors to improve its vehicles’ battery management systems.
“One of the issues with the battery is, when I step on the throttle hard, I’m pulling a lot of energy from the battery. And then, when I brake hard, I’m pulling a lot of energy out of the regen, but the batteries can’t take it fast enough. The batteries get really stressed when you try to pull it up too much, so if I had supercapacitors that I could use as a cushion; so when I need energy quickly, (I can) pull it from the supercapacitors and then fill the supercapacitors back up with the battery slowly; and then when I brake, I can capture more of that regen energy and do the supercapacitors faster. I think that just makes logical sense, because now all of a sudden I’ve got a sponge in front of my main energy source and I’m not stressing (the battery) so much,” Ellis said.
Tesla AI lead Ashok Elluswamy said this week that 24-hour Robotaxi service is close. Replying on X to a rider who wanted Cybercab trips all night, he wrote that the capability would arrive “next month or so” once “the next tech to merge on the v15 plan” is ready.
The comment landed on September 4, one day after Tesla opened public Cybercab rides in Austin. It is the clearest near-term timeline yet for overnight unsupervised operation. Tesla’s paid Robotaxi network currently runs from 6 a.m. to 10 p.m. seven days a week across Austin, Dallas, Houston, Miami, Orlando, and Tampa.
next month or so. the next tech to merge on the v15 plan will enable it.
— Ashok Elluswamy (@aelluswamy) September 4, 2026
That 16-hour window is shorter than the 6 a.m. to 2 a.m. schedule the company used for much of the prior year.
Elluswamy did not name the specific feature or say whether the change would apply first to purpose-built Cybercabs, the existing Model Y fleet, or both. He also offered no city-by-city rollout list. The link to Full Self-Driving v15 is nevertheless significant.
Tesla has described v15 as a step-change architecture with seven parallel improvement tracks and roughly ten times more parameters than earlier builds. Early versions of that software already operate on the Robotaxi fleet and contain about 40 percent of the planned gains.
By July 2026, the unsupervised fleet had logged more than 380,000 miles across six cities in two states with what the company called an impeccable safety record and no notable incidents caused by the vehicles themselves. Tesla has repeatedly argued that camera-based end-to-end neural networks, rather than extra sensors, are the core of the solution.
Overnight service would test that claim in lower-light conditions and would also raise vehicle utilization, a key variable for Robotaxi unit economics. The company has already begun using public Superchargers at night and is building dedicated Robotaxi charging sites.
Riders have asked why software must change if the cars already drive in the dark. The practical answer appears to be reliability and scale: Tesla has held back mass expansion until more of the v15 stack is merged, citing the need for higher confidence before putting thousands of unoccupied vehicles on streets around the clock.
If the next module arrives on the timetable Elluswamy sketched, 24-hour service could begin in October 2026 in at least some markets.
That would mark a shift from a daytime-bounded pilot to a service that can run whenever demand exists, including the late-night hours that have so far remained out of reach.
Tesla is beginning to roll out Full Self-Driving Supervised v14.3.9 with a new active safety layer that can take control even when the driver is operating the car manually.
Tesla AI said the software can activate FSD on the driver’s behalf when an imminent collision is detected and Automatic Emergency Braking may not be enough. It may also engage if the system detects heavy distraction or an accidental FSD disengagement.
FSD Supervised v14.3.9 starting to roll out shortly
This release includes a new active safety feature set: FSD Supervised can now activate on your behalf when an imminent collision is detected and Automatic Emergency Braking (AEB) may not be enough.
It may also engage if we…
— Tesla AI (@Tesla_AI) September 4, 2026
The capability is essentially Automatic Collision Evasion. However, unlike conventional AEB, which mainly applies the brakes in a straight line, this feature can use steering, braking, and acceleration together if the car calculates that stopping alone will not prevent impact and a safer path exists. The system may change lanes or move toward a shoulder when conditions allow, then continue driving after the immediate threat is handled rather than simply coming to a stop.
The intervention is meant as a last-resort safety net, not a replacement for attentive driving.
Tesla Full Self-Driving v14.3.7 early review: FSD saved me from an accident
Tesla’s own description still frames FSD as supervised assistance. Secondary reports on internal release notes say the feature can fire while the car is being driven manually if cabin-camera monitoring suggests the driver is not sufficiently attentive, such as reaching toward the back seat, or if FSD appears to have been turned off unintentionally.
After the emergency maneuver, the car is expected to alert the driver and request a return to manual control.
The safety case is straightforward. Many collisions happen in the last second because a driver is looking away, fumbles a control, or faces an obstacle that braking cannot fully solve. A system that can both recognize that AEB is insufficient and execute a coordinated evasive path can reduce those remaining high-severity events.
Re-engaging after accidental disengagement also addresses a practical failure mode: a small steering nudge that drops FSD at the worst moment. The advantage is a background safety net that uses the same vision stack already running in v14, instead of leaving the car solely to emergency braking once the driver is no longer in command.
The feature still depends on FSD being enabled and, according to reports, an active FSD purchase or subscription. It does not make the vehicle unsupervised. Drivers remain responsible, and Tesla has not published how often the system is expected to intervene or how it will handle false positives.
If the rollout is conservative and the false-alarm rate stays low, the update is a meaningful step: FSD is no longer only a feature the driver turns on. In the rare moments when disaster is already forming, it can step in.
Tesla launched the all-electric, steering wheel-less, and pedal-less Cybercab last night at a quiet and small event in downtown Austin, Texas.
The launch, which marked the beginning of unsupervised ride-hailing for Tesla’s Robotaxi platform with Cybercab, has already caught the attention of the National Highway Traffic Safety Administration (NHTSA) who has more questions.
NHTSA opened an Audit Query (AQ) into the Cybercab’s Federal Motor Vehicle Safety Standards (FMVSS) certification that Tesla gave the vehicle. Manufacturers self-certify vehicles much of the time to avoid excessive regulatory delays.
Tesla Cybercab interior, note the lack of steering wheel and pedals. (Credit: @niccruzpatane/X< /a>)
However, the agency needs more information; it said in a summary:
“On September 3, 2026, Tesla began commercial deployment with a small number of its Cybercab vehicles in Austin, Texas. Tesla notified the Agency that it certified those Cybercab vehicles as compliant with all applicable Federal Motor Vehicle Safety Standards (FMVSS). Tesla also notified the Agency that it plans to gradually expand commercial deployment of the Cybercab to include additional vehicles and locations.”
It also went on to state that the Cybercab lacks traditional automotive controls, which is a groundbreaking move. The process is entirely new to the NHTSA, which gives the agency some leverage to put Tesla’s launch under a microscope:
“The vehicles lack permanently attached, conventional manual controls, such as a brake pedal, gas pedal, steering wheel, and mirrors. NHTSA is opening this AQ to examine the process and technical data on which Tesla relied when certifying the Cybercab and related issues. Among other things, NHTSA will consider the extent to which Tesla’s certification depended on determinations that certain FMVSS are inapplicable to the Cybercab.”
Tesla has added 45 Cybercab units to its fleet of Robotaxi-enabled cars in Austin, according to public documents the company submitted to the State of Texas over the past week. Enabling this level of self-driving is something Tesla has worked toward for many years, and now that it is finally here, it seems more than reasonable that regulatory agencies will have some questions.
Many outlets might try to frame this as a negative, but it is truly an agency looking to gain more information about groundbreaking tech that Tesla has been developing for years.
In an effort to keep riders, pedestrians, and property safe, any and all data accumulated from these first days, weeks, and months of rides will likely be shared with the NHTSA to enable broader rollout strategies across the United States and more in the future.
Tesla Robotaxi will be a 24/7 service: here’s when
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