"The recall population includes certain Model Year (“MY”) 2025 Model 3 vehicles manufactured between March 8, 2025, and August 12, 2025, and MY 2026 Model Y vehicles manufactured between March 15, 2025, and August 15, 2025, that are equipped with a battery pack contactor manufactured with InTiCa solenoid."
The battery pack contactor is one of the only, if not actually the only, moving pieces in a battery pack. A solenoid connects or disconnects the battery pack from the rest of the car's electronics. In this case, it seems to fail in the open state, meaning the battery was not able to power the car. Either there was simply a bad production batch of these particular solenoids or a change in supplier for this part.
Model Ys still have a separate, standard 12V battery that power many of the car's non-drivetrain related parts. So in this case, the battery pack contactor failing open would cause the car to lose the ability to drive, but the doors/windows/lights/screen would all still likely be working.
That's not correct; you can say sentences like "The only moving parts in a dishwasher are the two pumps, the sprayer arms, the water inlet valve, and the detergent dispenser"; or "there are only two hard problems in computer science". So "one of the only" sounds just fine to me.
you can say sentences like "The only moving parts in a dishwasher are the two pumps, the sprayer arms, the water inlet valve, and the detergent dispenser"; or "there are only two hard problems in computer science".
In the dishwasher example, "only" refers to "moving parts" which is a collective singular, like how "baseball team" is properly an "it," not a "they."
Same goes for the compsci example. By modifying the plural with adjectives, you narrow its scope.
It's definitely not a collective singular, you say "the moving parts are", not "the moving parts is"; and "there are hard problems", not "there is hard problems".
Either way, the usage in the original comment was exactly the same as the dishwasher example: "the only moving parts are X, Y, and Z" => "X is one of the only moving parts".
"8 is one of the only" is a little off because it doesn't have an object, it relies on that being implicit from the prior sentence. "Only" here is an adjective, not a noun. The usage is a little awkward.
It would be more correct to say "there are only 4 positive integers less than 10. 8 is one of them."
Other automakers have recalls all the time too. Why is it that every single Tesla recall becomes national news, but virtually no recalls by other automakers ever do? (I can only think of two exceptions in recent history: Takata airbags and Chevy Bolt batteries.)
> virtually no recalls by other automakers ever do
That's wrong. There are regularly national news stories about recalls from other car brands. However, you'd still expect to see more Tesla news on HN because of the intersection with tech and startups.
Why is it that every single Tesla recall becomes national news, but virtually no recalls by other automakers ever do? (I can only think of two exceptions in recent history: Takata airbags and Chevy Bolt batteries.)
Maybe you don't read enough legitimate/mainstream media? I see them all the time.
but how notable was it? In other words was it on the front page either online or in print? The nature of publishing nowadays is that virtually unlimited amounts of articles can be published, but unless you're seeking them out you're not going to stumble upon them like this post.
You only stumbled across this post because you are part of the relatively niche community of HN. It is not a sign of notability. At most its a sign of targeting this demographic.
What about the Hyundai/Kia antitheft recalls? Those dominated the news for /years/.
You’re not actually asking about media fairness. You’re defending Elon Musk under the usual “everyone’s unfair to Elon” routine. Now think about the difference in public visibility between the Ford CEO and the Tesla CEO. Which one’s name alone drives more clicks and engagement?
Musk injects himself into the news constantly. When you build your brand on publicity, you also get the scrutiny that comes with it. No need to play at the victim narrative.
...... Huh? Kia and Hyundai's recalls for the trailer hitch wiring fire recall made national news. Toyota's recall of the rear view camera issue on the 2025 trucks too.
Granted I'm Canadian so that might make a difference, but Tesla recalls aren't the only one making national new. They just don't typically appear on Hacker News.
y'all ever notice that the internet seems to have introduced entire new classes of fallacy, or at least that the structure of debating online tends to surface fallacies that aren't as common in real life? This is one that I call the redditor fallacy and at its base it's the presumption that if one particular group of people isn't currently talking about something in one particular thread that no one anywhere is talking about it and it's a subtype of whataboutism. The truth is that if I google the phrase "automobile recall" I don't see tesla in the first three pages of results but I do see Ford, GM, Nissan, Dodge and Volkswagen.
I've owned three Audis over the last decade with no recalls
Tesla deliberately pushes boundaries and breaks from tradition. That's admirable, but traditional manufacturers have decades of engineering knowledge behind their approaches for good reasons. Push the envelope enough and you'll have more misses and in Tesla's case more recalls
You are making things up out of thin air. These are recalls from JAN 2024- MAR 2025
Ford Motor Company, 94 (7%)
Chrysler (FCA US, LLC), 78 (6%)
Forest River, Inc., 67 (5%)
General Motors, LLC, 41 (3%)
BMW of North America, LLC, 39 (3%)
Mercedes-Benz USA, LLC, 33 (3%)
Hyundai Motor America, 28 (2%)
Jaguar Land Rover North America, LLC, 26 (2%)
Volkswagen Group of America, Inc., 25 (2%)
Daimler Trucks North America, LLC, 24 (2%)
Honda (American Honda Motor Co.), 24 (2%)
Kia America, Inc., 24 (2%)
Jayco, Inc., 22 (2%)
International Motors, LLC, 21 (2%)
Nova Bus (US) Inc., 21 (2%)
Toyota Motor Engineering & Manufacturing, 21 (2%)
Nissan North America, Inc., 20 (2%)
Tesla, Inc., 20 (2%)
Mack Trucks, Inc., 17 (1%)
Winnebago Industries, Inc., 16 (1%)
Ratio of U.S. vehicles recalled in 2024 → 2024 U.S. sales
Tesla: 5,135,991 → 516,597 ≈ 9.94.
Ford: 4,777,161 → 2,078,832 ≈ 2.30.
GM: 1,872,567 → 2,700,000 ≈ 0.69.
Toyota: 1,221,666 → 2,330,000 ≈ 0.52.
Honda: 3,794,113 → 1,291,490 ≈ 2.94.
A Tesla sold in 2024 was roughly 4 times more likely than a Ford to be involved in a recall campaign that year.
Despite selling far fewer vehicles, Tesla’s recalls affected nearly ten times its annual U.S. sales volume.
This reflects a structural difference, not media bias. Tesla initiates fewer recall campaigns overall, but those campaigns routinely involve millions of vehicles. When normalized for sales volume, Tesla’s recall exposure is the highest of any major automaker. “Innovation risk” cuts both ways.
What happens in the edge case of losing HV during heavy braking on the freeway? Does the brake booster still function independently of the HV system, or is the driver going to have to push the pedal a lot harder?
Nothing immediately - Teslas have a both a High Voltage system for the traction battery and a Low Voltage system powered by a separate 12-15V battery. The HV system keeps the LV system charged and most critical safety related functions run on the 12V system. The booster, ABS/ESP, airbags, and steering assist are all designed to remain functional long enough for a controlled stop after an HV disconnection.
You obviously wouldn't be able to speed up again, which depending on the situation, would be where the danger lies.
Tesla have done a lot of vertical integration, but for other manufacturers there's a lot of common electronic components. Stuff like headlamps (even if it's a different plastic housing the board will be the same basic design), door locks, infotainment, dashboard displays where there's little reason to significantly reengineer them for an EV.
Not only is the majority of an EV the exact same components as an ICE car, but the electric car industry has been using off the shelf components for decades.
Tesla buys plenty of products from them, including things like electric steering assist.
Bosch wants to stay relevant for longer than ICE cars after all, and a lot of these components were developed for ICE cars anyway.
I don't think it would have to be only electric cars, if you're building a hybrid where the 12V battery is kept charged by the high voltage battery, you've got basically the same situation.
Availability of accessories seems like it would be inconvenient for any early adopters, e.g. you can readily get USB chargers, portable generators, coolers, tire inflators, battery boosters, etc. that run off 12V... if you get a 48V vehicle today, you'd either need a 110V->12V adapter to run accessories, or you'd be limited to 48V RV accessories.
Virtually all electronics need a step down (buck) converters as they run at lower voltages 5, 3.3, 1.8. 12V > 3.3- 1V would a single step. 48V ones would likely require an intermediate step. The only exception would be running some power systems where it'd require less current.
The move to 48v is very much about efficiency within the harness backbone. For the same wattage, less amperage is needed in a higher voltage system, meaning the wires can be smaller and they produce less waste heat.
There are a few different topologies for a 48v harness, but somewhere in the line there's a 12V DC/DC converter in there somewhere.
You're going to need the expensive bits of a power supply anyway to meet transient requirements, so it's not much of a savings to run at native voltage and it gives a lot of design freedom/reusability to have one voltage for everything.
The main savings is current though, because the wiring harness is one of the most expensive parts of a car.
The wiring for 48V can be a lot thinner than it is for 12V. As there is a square law involved for resistive heating it turns out that wiring for 48V can use 1/16th of the weight of copper as that for 12V.
A switchmode converter can be designed for 48V just as easily as 12V.
It's far cheaper and easier to just pluck a readily available 12V power supply off the shelf than it is to design one that will have limited applications outside of a single manufacturer.
Because all of the IC's that are attached to the battery are designed for 12V. Things like solid state relays (BTS7008 for exammple) and the 5/3.3 volt regulators.
The vacuum reservoir of the brake booster in cars with vacuum servo brakes (whether vacuum is generated by the engine or an electric pump is irrelevant) stores enough energy for 3-4 full applications of the brakes.
EV don’t use vacuum break booster systems anymore. There are much better and more efficient fully electric break booster systems out there which make a lot more sense.
Vacuum break boosters only make sense for ICE vehicles where you already have an existing air pump (the actual engine) providing free “vacuum”, they don’t make sense in EVs where you need to an extra dedicated motor to produce vacuum, to power a vacuum booster system, to boost the breaks. Much better off just using the extra electric motor to directly boost breaks, without the whole vacuum system as a middle man.
Early EVs use vacuum break boosters, but only because they were the only economical solution, given there was little demand for electric break booster systems. After all a vacuum system is cheaper, if you have a free “vacuum source”. But for last decade or so there’s been enough EVs manufactured that electric break booster systems are now more economical for EVs.
To answer GP question, the an electric break booster system is almost certainly powered off the low voltage (12V) accessory system, not the high voltage system. So a high voltage disconnect won’t prevent the break booster from working, assuming the LV battery is working correctly.
That's not reassuring. This recall is the exception. The low voltage 12V battery has been far more unreliable in EV's from all brands than the high voltage battery has been.
Is an EV like an ICE in that the 12V bus has power while the car is running even if the 12V battery is dead? In an ICE the alternator puts 13.5 volts onto the 12V bus so a dead battery will prevent a car from starting but it will stay running on a dead battery if boosted to start. I imagine an EV does something similar but I don't know.
> "The low voltage 12V battery has been far more unreliable in EV's from all brands than the high voltage battery has been."
Some EV makers, including Tesla, have switched to Li-ion (often LFP) low-voltage batteries. These tend to be better suited to EV duty cycles than lead-acid, and improve reliability and longevity, as well as saving space and weight.
If the car is on (high voltage battery pack energized) then there is 12V supplied from the high voltage pack through a DC to DC converter.
The 12V battery dying is only an issue if the car is parked and the high voltage battery is disconnected. Then there may not be enough power to 'wake' the car up again.
I can't speak for all EVs but my Ford with a 400v hybrid system (DC-to-DC, no alternator) was able to keep operating perfectly with no 12v battery whatsoever. There was an assembly defect where the positive terminal connecting the battery to the fuse box eventually came partially loose and would disconnect as the engine bay warmed up. It would start up fine and drive with zero issues but then completely black out as soon as the car was turned off.
In a lot of EVs, when the car is "on" there is a DC/DC converter powering the 12V system from the HV battery. So if the car was "on" and experienced a loss of the 12V battery it could continue operating for some period of time.
I think the implication is that people could be driving with a dead 12V as if nothing is wrong. Then when they experience the HV failure in the recall, they would have no power whatsoever for safety systems.
That wasn't intended to be my implication. The replies to the original comment answered my question. Generally if you have a dead 12V you know it because you need a boost to get started, and you don't drive like that for long. I'm not worried about a cascade failure, I was worried about the 12V dying while somebody was driving and then having no brakes. That concern has been addressed.
When the 12v battery is dying, at least in a Tesla, it warns you, and starts disabling certain features, more likely to help preserve the battery. For example, heated seats run off 12v. It makes sense that a lot of commodity auto industry parts would run off 12v because the supply chain is there, and because you want low voltage in the cabin anyway.
Like another poster in this thread, my original model 3 battery went ~5 years (typical 12v failure age in a car), and I bought it for $89(!!) at Tesla. Autozone wanted $125 for the same group battery. I did a DIY replacement. For some reason, that one failed after a year and a half. Just bad luck I guess.
Yes, this drives a requirement for latent fault detection of LV battery faults. In general when a safety function is decomposed to provide statistical safety, there is a requirement to time-bound a single failure, since without that the decomposition doesn’t buy you anything. Latent fault detection is the standard option for time bounding for automotive — for aviation, you have a second escape hatch that issues that are reliably found during annual / 100 hour inspection and can be safely missed for that long can be caught by inspection instead.
> EV don’t use vacuum break booster systems anymore. There are much better and more efficient fully electric break booster systems out there which make a lot more sense.
To lecture us on EV brake systems while repeatedly misspelling the word is making me twitch far too early this otherwise fine Wednesday morning.
The brake booster should have enough pressure for a few seconds of hard braking. They commonly fail on my vehicle (2003 LX470) and most people get a warning during failure and are able to come to a stop during the short few second window.
Tesla brakes are conventional. Yes, the driver has to push harder if the hydraulics fail, same as any car. There's nothing unique to the failure here, normal cars run their boosters off of the power train too (via belts or vacuum usually, also some have 12V pumps and would be subject to exactly this kind failure).
As to whether the booster is run off of the 400V or 12V bus I don't actually know. My guess would be the latter, honestly, since the parts would be more generic. But in any case it probably doesn't matter if the main battery fails as the 12V battery is tiny and would probably not provide enough power to run the hydraulics without the DC/DC converter.
>12V battery is tiny and would probably not provide enough power
LiFePO4 is capable of providing massive amounts of current for its size (way higher than a conventional acid one). 100A is not that high amount of current to run even with 4s4p setup. A 10kg battery would be beyond sufficient (should be able to fully power the brake system for 1h use).
Note: jump on the brakes is expected to consume around 1200W
2kg would be a monster of a laptop battery of course, esp since it's regular Li-Ion (not the one w/ Fe/P). LiFePO4 should be ~150Wh/kg. So indeed, the battery is 'tiny', like 1kg only. Yet, it'd have no issue supplying the brakes - it's less than 10C discharge rate. LiFePO4 tends to have much higher discharge rate which is the important part not the total capacity.
Because it fundamentally is just a laptop battery. The job of the 12V bootstrap battery is to bring the main control hardware (not even the MCU, I don't think) online so that the DC/DC converter can power the 12V bus from the main battery. There are a few other systems that expect to be powered in the event of a main battery failure, like door locks and charging.
But I really don't think hydraulics like power steering/braking are on that list. The fallback for hydraulic failure is manual pressure, just like it is on any car. It's a naturally redundant system.
I don't doubt you could run into problems in extreme cold, but our Model Y SR (LFP pack) has been fine charging in -5C or so. The car is pretty good at managing thermals and making sure the battery doesn't get too cold.
Seems really odd to me to have 400V brake regeneration and run the brake booster off of 12V, but quick searches don't reveal the answer for a Tesla or even a Prius.
The most recent Teslas (Model Y Juniper) have gotten a bit less conventional as they now have blended braking. ie: the brake pedal controls both regenerative and friction brakes, with the brake pedal "feel" effectively implemented by software.
> At the bottom of the rear door pocket, there is a slot in front of the release cover. Slide your finger into the slot and lift to remove the cover. Pull the mechanical release cable forward.
I wonder how people are supposed to be able to find that when in an emergency sitting in the backseat of someone else's car.
They're in even worse luck if they are in any number of cars that have rear-seat "child safety" locks that prevent opening the door from the inside. There's no way to bypass that except from outside the car.
Yeah, that's terrifying as well, but I think it's the same for all car manufacturers about that, isn't it? Or is some makers worse than all the others because of design decisions?
That sounds pretty good in comparison to the Cybertruck, because that one can't be opened from the outside ever, if the battery dies.
The manual bypass for the driver and passenger seat is much easier to find than the one in the rear. Too bad the driver can't help rescue everyone else, because the door handles are electric.
The front doors have a way easier and more obvious way than the rear doors. In fact, for the front doors it's so obvious that most passengers think it's the normal way to open the door. The reason the rear doors have it much more hidden is because child safety locks are an important safety feature, and they'd be useless if small children could easily bypass them.
Yeah but the back seat is more likely to have children or passengers unfamiliar with the car too so an esoteric emergency procedure is worse there. IMO these cable unlocks shouldn't be allowed for safety, there should be an obvious easy mechanical release people understand which is a normal handle.
It's only hidden for the back doors so that it doesn't render the child safety lock useless. It's in the most obvious spot possible for the front doors.
This question is misleading for the same reason "have you stopped beating your wife?" is. Even if a Tesla loses all power, you can still open the doors with a mechanical handle and escape. Tesla's engineers aren't stupid.
A more apt comparison would be a fuel pump, since fuel tanks don't really stop working short of springing a leak which brings its own problems.
Fuel pump failure is certainly not an uncommon thing, although in my limited experience, they usually become a bit intermittent and the car sputters for awhile, rather than losing all motive power at once (but that's totally possible too).
I am guessing when drive power is lost on an EV it would just coast (hopefully). Since there's effectively no connected battery pack to regen to, and the electric motors won't physically lock up.
Given that it is a car post Internal Combustion Engine would be my first guess when seeing ICE but I can see where one might think of the other as well.
> I wonder how they compare to the rest of the auto manufacturers, in this regard.
Most recalls in 2024: Chrysler (72), Ford (67), BMW (36), GM (34), Hyundai (25), Mercedes-Benz (28)
Least: Tesla (16), Mazda (6), Rivian (8), Nissan (18), Toyota (16), Porsche (13)
Another way to look at it is number of people impacted, which changes the "leaderboard". In order of most people to least: Tesla, Chrysler, Ford, Honda, GM, BMW, Kia, Toyota,.... Porsche. Obviously, conflating factor is popularity of brand.
Tesla has many small tweaks on their cars from year-to-year and even less. It's not as bad as it used to be (I haven't heard of any plywood in use inside the componentry).
Fords recall numbers have skyrocketed in recent years. So Fords real comparison to its previous self, 2015 they had 68. Why isn’t Fords roughly doubling of recalls news?
It's reasonably well known that Ford has had a very bad year for recalls; it's definitely made the rounds in the auto world, and breaks through to the mainstream news from time to time.
>Why isn’t Fords roughly doubling of recalls news?
Oh, I don't know, maybe because Tesla is bigger than the rest of the entire industry combined?
Besides, safety recalls are what matters. I get lots of small qualtiy-related recalls that are so minor I don't even bother getting them done. Meanwhile, Tesla does what it can to avoid quality recalls, because for a while it was a marketing blurb for them.
> Oh, so this is an actual recall and not just a software update.
In an era of software-defined vehicles, the difference is one of convenience, not impact/consequence. Not really worth pointing out, unless you're a service department telling owners how to plan their week.
No, but we own one of their vehicles and in years have never experienced a recall that involved physically recalling the vehicle. This one doesn't apply to us, but if it did, that alone would immediately make it stand out compared to every other recall we've experienced with the product (which have never had any effect on us whatsoever).
The thing is, to most people, "recall" is a strong word that carries major implications.
Yeah, sure, you might be smart enough to understand that the word has a legal definition, and sometimes a recall is an absolute nothingburger. For example, Tesla once had to do a recall because some warning icons on the screen were legally deemed to be a couple pixels too small. Yet, when news outlets announce "Tesla recalls every Model 3 ever made", it's TECHNICALLY true, but will be highly misleading to the general population who now thinks every Model 3 has to be returned.
EDIT: Also, FWIW, even when a recall DOES require a physical change of the car, Tesla's mobile service can often come to you to do it. You don't need to take it to a service center.
That’s nonsensical, IMO. Software updates should not be considered recalls at all. Unless it’s a critical safety issue that makes the vehicle unusable.
Awesome. Let's do that, right after we stop calling "place this sticker, which contains a warning about materials in the seatbelt tensioner system, on page 234 of your owner's manual" a recall, too.
On the topic of recalls in general. An old buddy of mine in the auto industry believed that legacy automakers would do bogus or superfluous recalls on occasion just to get people back into the dealership. Where sales people could mosey into the service area and talk to the folks with older cars.
No hard evidence for it, but it did make me think. (I don't think this applies to Tesla)
https://electrek.co/2025/10/22/tesla-recalls-recent-model-3-...
Model Ys still have a separate, standard 12V battery that power many of the car's non-drivetrain related parts. So in this case, the battery pack contactor failing open would cause the car to lose the ability to drive, but the doors/windows/lights/screen would all still likely be working.
Pet peeve: The phrase is "one of the few," not "one of the only." If something is "only," it can't be "one of" something.
In the dishwasher example, "only" refers to "moving parts" which is a collective singular, like how "baseball team" is properly an "it," not a "they."
Same goes for the compsci example. By modifying the plural with adjectives, you narrow its scope.
Either way, the usage in the original comment was exactly the same as the dishwasher example: "the only moving parts are X, Y, and Z" => "X is one of the only moving parts".
https://www.merriam-webster.com/dictionary/only
https://www.merriam-webster.com/dictionary/one%20of%20the%20...
It would be more correct to say "there are only 4 positive integers less than 10. 8 is one of them."
It is perfectly acceptable to use only to refer to a select group.
That's wrong. There are regularly national news stories about recalls from other car brands. However, you'd still expect to see more Tesla news on HN because of the intersection with tech and startups.
Theres always someone complaining about or defending negative Tesla news here for the same reason, but less so because of the drivers.
- Tesla PR department = { } // the empty set
- CEO drives all external communication (pun intended)
Maybe you don't read enough legitimate/mainstream media? I see them all the time.
Just yesterday: Ford, Dodge, Nissan among over 1.1 million vehicles recalled - https://www.usatoday.com/story/cars/recalls/2025/10/20/check...
It doesn't get much more "national" than USA Today.
Hacker News seems to post Tesla recalls, but national news websites that publish recalls seem to do it for every single recall, not just Tesla.
but how notable was it? In other words was it on the front page either online or in print? The nature of publishing nowadays is that virtually unlimited amounts of articles can be published, but unless you're seeking them out you're not going to stumble upon them like this post.
You’re not actually asking about media fairness. You’re defending Elon Musk under the usual “everyone’s unfair to Elon” routine. Now think about the difference in public visibility between the Ford CEO and the Tesla CEO. Which one’s name alone drives more clicks and engagement?
Musk injects himself into the news constantly. When you build your brand on publicity, you also get the scrutiny that comes with it. No need to play at the victim narrative.
Granted I'm Canadian so that might make a difference, but Tesla recalls aren't the only one making national new. They just don't typically appear on Hacker News.
Tesla deliberately pushes boundaries and breaks from tradition. That's admirable, but traditional manufacturers have decades of engineering knowledge behind their approaches for good reasons. Push the envelope enough and you'll have more misses and in Tesla's case more recalls
Tesla: 5,135,991 → 516,597 ≈ 9.94.
Ford: 4,777,161 → 2,078,832 ≈ 2.30.
GM: 1,872,567 → 2,700,000 ≈ 0.69.
Toyota: 1,221,666 → 2,330,000 ≈ 0.52.
Honda: 3,794,113 → 1,291,490 ≈ 2.94.
A Tesla sold in 2024 was roughly 4 times more likely than a Ford to be involved in a recall campaign that year. Despite selling far fewer vehicles, Tesla’s recalls affected nearly ten times its annual U.S. sales volume.
This reflects a structural difference, not media bias. Tesla initiates fewer recall campaigns overall, but those campaigns routinely involve millions of vehicles. When normalized for sales volume, Tesla’s recall exposure is the highest of any major automaker. “Innovation risk” cuts both ways.
https://www.kbb.com/audi/recall/
The entire car dealership lobby hates Tesla, for example.
You obviously wouldn't be able to speed up again, which depending on the situation, would be where the danger lies.
But e.g. why have different electric window motors, wiper motors, turn signal solenoids etc etc?
Tesla buys plenty of products from them, including things like electric steering assist.
Bosch wants to stay relevant for longer than ICE cars after all, and a lot of these components were developed for ICE cars anyway.
Availability of accessories seems like it would be inconvenient for any early adopters, e.g. you can readily get USB chargers, portable generators, coolers, tire inflators, battery boosters, etc. that run off 12V... if you get a 48V vehicle today, you'd either need a 110V->12V adapter to run accessories, or you'd be limited to 48V RV accessories.
Virtually all electronics need a step down (buck) converters as they run at lower voltages 5, 3.3, 1.8. 12V > 3.3- 1V would a single step. 48V ones would likely require an intermediate step. The only exception would be running some power systems where it'd require less current.
There are a few different topologies for a 48v harness, but somewhere in the line there's a 12V DC/DC converter in there somewhere.
The main savings is current though, because the wiring harness is one of the most expensive parts of a car.
The wiring for 48V can be a lot thinner than it is for 12V. As there is a square law involved for resistive heating it turns out that wiring for 48V can use 1/16th of the weight of copper as that for 12V.
A switchmode converter can be designed for 48V just as easily as 12V.
Hobbyist computing could benefit from a move to 48V as well, if only to keep the problematic 12VHPWR from killing expensive video cards.
I say hobbyist because AIUI 48v is making inroads in server hardware but that's not my area.
You generally can't reuse non-automotive power supplies in automotive because the requirements are very different.
I have to wonder if this ever happened with the 6v to 12v transition somewhere in the 50's-60's
Vacuum break boosters only make sense for ICE vehicles where you already have an existing air pump (the actual engine) providing free “vacuum”, they don’t make sense in EVs where you need to an extra dedicated motor to produce vacuum, to power a vacuum booster system, to boost the breaks. Much better off just using the extra electric motor to directly boost breaks, without the whole vacuum system as a middle man.
Early EVs use vacuum break boosters, but only because they were the only economical solution, given there was little demand for electric break booster systems. After all a vacuum system is cheaper, if you have a free “vacuum source”. But for last decade or so there’s been enough EVs manufactured that electric break booster systems are now more economical for EVs.
To answer GP question, the an electric break booster system is almost certainly powered off the low voltage (12V) accessory system, not the high voltage system. So a high voltage disconnect won’t prevent the break booster from working, assuming the LV battery is working correctly.
Is an EV like an ICE in that the 12V bus has power while the car is running even if the 12V battery is dead? In an ICE the alternator puts 13.5 volts onto the 12V bus so a dead battery will prevent a car from starting but it will stay running on a dead battery if boosted to start. I imagine an EV does something similar but I don't know.
Some EV makers, including Tesla, have switched to Li-ion (often LFP) low-voltage batteries. These tend to be better suited to EV duty cycles than lead-acid, and improve reliability and longevity, as well as saving space and weight.
The 12V battery dying is only an issue if the car is parked and the high voltage battery is disconnected. Then there may not be enough power to 'wake' the car up again.
Like another poster in this thread, my original model 3 battery went ~5 years (typical 12v failure age in a car), and I bought it for $89(!!) at Tesla. Autozone wanted $125 for the same group battery. I did a DIY replacement. For some reason, that one failed after a year and a half. Just bad luck I guess.
Mine failed after ~5 years. Replacement was inexpensive ($128) and Tesla service drove to my house to install it.
To lecture us on EV brake systems while repeatedly misspelling the word is making me twitch far too early this otherwise fine Wednesday morning.
[1]: https://www.youtube.com/watch?v=SRZ8XDNz2vU
As to whether the booster is run off of the 400V or 12V bus I don't actually know. My guess would be the latter, honestly, since the parts would be more generic. But in any case it probably doesn't matter if the main battery fails as the 12V battery is tiny and would probably not provide enough power to run the hydraulics without the DC/DC converter.
LiFePO4 is capable of providing massive amounts of current for its size (way higher than a conventional acid one). 100A is not that high amount of current to run even with 4s4p setup. A 10kg battery would be beyond sufficient (should be able to fully power the brake system for 1h use).
Note: jump on the brakes is expected to consume around 1200W
I don't have the exact weight, but Tesla's LFP low-voltage batteries weigh far less than that. Around 2kg at a guess.
Rating is 12.8V nominal, 12Ah, 153.6Wh. Not all that much bigger than a laptop battery!
Either way, the battery is indeed 'tiny'
But I really don't think hydraulics like power steering/braking are on that list. The fallback for hydraulic failure is manual pressure, just like it is on any car. It's a naturally redundant system.
Again, Tesla brakes are very conventional hydraulic devices and they work (and fail) like brakes in any other car you're going to drive.
> At the bottom of the rear door pocket, there is a slot in front of the release cover. Slide your finger into the slot and lift to remove the cover. Pull the mechanical release cable forward.
I wonder how people are supposed to be able to find that when in an emergency sitting in the backseat of someone else's car.
The manual bypass for the driver and passenger seat is much easier to find than the one in the rear. Too bad the driver can't help rescue everyone else, because the door handles are electric.
I point them out to any passengers in the back seat.
If you have kids that are likely to pull them ... different story.
https://people.com/woman-dies-after-allegedly-being-trapped-...
https://nypost.com/2025/09/19/world-news/tesla-driver-and-tw...
FTFY
Fuel pump failure is certainly not an uncommon thing, although in my limited experience, they usually become a bit intermittent and the car sputters for awhile, rather than losing all motive power at once (but that's totally possible too).
I am guessing when drive power is lost on an EV it would just coast (hopefully). Since there's effectively no connected battery pack to regen to, and the electric motors won't physically lock up.
https://static.nhtsa.gov/odi/rcl/2018/RCRIT-18V160-2117.pdf
I try to avoid political news but am apparently failing at some level.
There were millions of Americans who were very confused in 2020 when BLM protests popped up in other parts of the country.
"Why do they hate the Bureau of Land Management?"
Most recalls in 2024: Chrysler (72), Ford (67), BMW (36), GM (34), Hyundai (25), Mercedes-Benz (28)
Least: Tesla (16), Mazda (6), Rivian (8), Nissan (18), Toyota (16), Porsche (13)
Another way to look at it is number of people impacted, which changes the "leaderboard". In order of most people to least: Tesla, Chrysler, Ford, Honda, GM, BMW, Kia, Toyota,.... Porsche. Obviously, conflating factor is popularity of brand.
Source: https://brclegal.com/us-car-recall-statistics/
https://www.motortrend.com/news/2024-2026-ford-ranger-recall...
https://247wallst.com/investing/2025/10/17/ford-recall-recor...
https://www.usatoday.com/story/cars/recalls/2025/09/24/ford-...
https://www.macheforum.com/site/threads/ford-issues-more-saf...
Oh, I don't know, maybe because Tesla is bigger than the rest of the entire industry combined?
Besides, safety recalls are what matters. I get lots of small qualtiy-related recalls that are so minor I don't even bother getting them done. Meanwhile, Tesla does what it can to avoid quality recalls, because for a while it was a marketing blurb for them.
If you're looking at the pie chart, Tesla is not shown, but has had 9 in whatever time period and selection criteria is used.
In an era of software-defined vehicles, the difference is one of convenience, not impact/consequence. Not really worth pointing out, unless you're a service department telling owners how to plan their week.
Yeah, sure, you might be smart enough to understand that the word has a legal definition, and sometimes a recall is an absolute nothingburger. For example, Tesla once had to do a recall because some warning icons on the screen were legally deemed to be a couple pixels too small. Yet, when news outlets announce "Tesla recalls every Model 3 ever made", it's TECHNICALLY true, but will be highly misleading to the general population who now thinks every Model 3 has to be returned.
EDIT: Also, FWIW, even when a recall DOES require a physical change of the car, Tesla's mobile service can often come to you to do it. You don't need to take it to a service center.
I threw up in my mouth a little upon reading this phrase. Dark times.
Past Tesla recalls addressed by OTA updates include fixes for braking, steering, headlights, tire pressure monitoring, collision avoidance, etc...
https://www.cars.com/research/tesla/recalls/
The whining about this is old.
No hard evidence for it, but it did make me think. (I don't think this applies to Tesla)