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Personally I would have liked to see the reasoning presented in that safety message. Something like "high voltage is present under the hood" or "only qualified personnel have the tools to safely open the hood".

Same applies for your no trespassing example. I would like to see "no trespassing, danger high voltage"

This.

Plenty of people think they're "smart" - and assume they know better than a vague warning sign: When some people see a "Danger confined space" sign they're going to think the danger is banging your head on the low-ceiling; that's not the real danger of confined spaces: a bigger threat is unbreathable gasses, like CO2, that tend to pool at the bottom of confined spaces: that's often the real danger. But yet I've never seen a sign saying "Danger: confined space: CO2 pooling risk" or similar.

There’s no warning sign for CO2 risk that will work for a non-expert. You have to go for the basics (“risk of suffocation and death”) at that point, because no one knows that you can drown in CO2.

These ones would work for me:

"CO2 pooling risk" "Gas pooling risk" "Risk of suffocation"

“There’s no visible pool of water, must be fine”

I disagree. I think that most of the population of United States would understand that oxygen deprivation is bad. I agree that coming up with verbiage for a sign that clearly communicates the correct intent would be difficult.

This. But the problem aren't the people, but the vague warning sign. Another example is

The problem is that many warning signs don't exist to warn people, but to prevent lawsuits. So they are phrased as generally as possible and often include false positives.

Isn't that kindof what the list of warnings below the message provides? I think you can click on them to expand them, and based on what's in the owner's manual I expect one of the warnings is about "components under voltage".

Definitely agree. My first thought was "but yes", after reading the article I am not so curious to peek under. Perhaps the marketing department doesn't like the idea of the car being "danger"-ous.

I don't think there are really any major risks to human life from the high voltage under the hood of an EV.

The electrical system checks for earth leakage faults all the time, and will switch off if it finds one. That means a baby can chew any of the big scary orange wires and still survive.

The only real dangerous bit of an EV is the battery pack - if you cut it open.

In your case it appears that Mercedes made the right decision. 400 V DC with for all practical purposes an internal resistance so low that it might as well be zero is about as nasty as it gets. Zero warning until you touch that live terminal and then no way to disconnect if you happened to grip it the wrong way, and when you short it out you're going to be in for a world of hurt.

The earth leakage protection only applies to the charging circuitry primary.

So, even if I don't agree with the principle it looks like for some users this actually applies, which I find somewhat surprising.

The earth leakage protection applies to the whole system.

> no way to disconnect if you happened to grip it the wrong way

This is what the explosive breakers are for.

Here is an article with more details:

https://www.vehicleservicepros.com/service-repair/battery-an...

Note that it appears there are a few hybrid cars made in the 90's without this protection!

This is only about chassis ground current, not earth leakage, which is strictly the domain of the charging circuitry.

Seriously: if you do not understand the difference please do no not start messing with the HV side of an electric vehicle. Below 48 V is considered a safe voltage but can already - under the right conditions - cause you plenty of hardship and I'm aware of one death from a 48 V system.

Anything higher than that with voltages between 200 and 600V pretty much the nastiest range because it is too low to arc and high enough to kill you needs special precautions, tools and ways of working to keep you safe.

You can't rely on technical measures to keep you safe when diagnosing and repairing those circuits because those technical measures could be the cause of the fault.

The explosive Breakers would not help you in this case. Those Breakers likely blow in hundreds of amps range, you only need one 100th of an amp to stop your heart.

Don't worry buddy we'll do everything we can to get those enhanced warning messages out there so you can be safe too.

Oh, your car can kill you or injure you in so many ways when it's turned off. You could accidentally disconnect something from the coolants system before it cooled down and get third degree burns. You could accidentally start the engine when working on the electric system and kill yourself. You could start a fire in about a dozen different ways and kill yourself or someone else. You can also accidentally leak battery fluid onto yourself or blow up the battery, and breathe in toxic gases.

There are also a few dozen ways you could mess up a repair and die without warning while driving.

None of those are in the same “likelihood of death to a person who has common sense” risk category as the high-voltage Mercedes front compartment. See also the various other replies along these lines, such as:

https://news.ycombinator.com/item?id=29801119

Another way to look at this is, “are there any consumer-serviceable parts within the compartment?” and “are there instantly-fatal wires/terminals within the compartment?”. The pair of answers “no” and “yes” for the Mercedes demand a wholly different approach to risk management and safety design than a gas engine, whose pair of answers are “yes” and “no”.

EV high-voltage are not consumer-serviceable, as a regular consumer cannot be expected to understand high-voltage safety practices. Yes, some consumers know how to service them, but the necessary safety practices that are generally commonly understood for gas engines are not commonly understood for electric engines, and are regulated differently as a result.

"Consumer-serviceable parts" is such a stupid term. There are actually no parts that are "consumer serviceable", because a "consumer" is an abstract fiction that is only capable of continually buying new off-the-shelf junk. In reality, these devices are owned by people, most of them quite capable of replacing parts, especially when they're not being infantilized.

The main thing that has changed between traditional cars and EVs are the times. The specific hazards are different and some amount of warning is justified, but plastering something with useless signs that just attempt to discourage without describing the actual hazards should create the same legal situation as having no warnings at all.

Please forgive the insult of my choice of wording — I made up a phrase on the spot and it is clearly unacceptable. I’m sorry. In any case, we disagree, so I won’t try to offer a replacement as the intent of my viewpoint has already been conveyed adequately.

I didn't mean to pick on you directly, but the wider consumer-serviceable / user-serviceable meme. I've seen far too many labels asserting such nonsense.

That's stupid. If you're assuming common sense, common sense is to not cut open thick cables without ensuring they're disconnected. It's just as much common sense as not working on your car with it's engine on.

"Consumer-serviceable" parts don't exist. That being said, yes, you may want to replace the HEPA filter, or any other parts in the ventilation system, for example.

High voltage safety pracitces are simple in this case. Is the battery completely disconnected from the rest of the car? Yes? Then it's safe. No? Then the car is on, and it's not safe, just like any vehicle.

If Mercedes don't make available a way to ensure the main battery is disconnected and no high-voltage circuit is energized, that's on them, and they are 100% in the wrong. Otherwise, there is an easy, common-sense way to make all of this safe for your average Bozo to work on.

And by the way, this is a much higher standard than the one we use today. I can happily go an kill myself by fucking up my brake system. No one will stop me. Why is this off-limits, then?

> None of those are in the same “likelihood of death to a person who has common sense” risk category as the high-voltage

High voltage in cars is actually very safe. The car constantly checks for leakage current and switches off if any is seen. That means you could cut through a high voltage cable while driving with uninsulated pliers and survive.

Warning:. Many of these safety systems are single-use explosives. After doing this, the repair will be expensive...

Indeed. You don't want to rely on these, though, and it is a design failure if the manufacturer doesn't make available a way to safely disconnect the HV systems to the user.

Wow. Normally cars just kill everyone else. 2 million people every year.

I feel in that case securing the hood with bolts in the grille or whatever would do a better job of discouraging random motorists from poking around there for a spare tire while still allowing the slightly mechanically inclined to open it and discover the EQS's "secret" of poor HVAC routing. Having the UI actively berate you about safety is both demeaning to the customer and toxic to repair culture as a whole.

like other posters have mentioned, there's a legal/liability component too. bolts don't prevent lawsuits, warning labels/messages do.

There is no liability component to a car's engine compartment.

For a hundred years car engine compartments have been dangerous as hell.

Hazards in an ICE compartment:

* temperatures hot enough to melt/set fire to your clothing (the exhaust, which in modern engines can be found in all sorts of weird places; Audi and others now use turbochargers inside the engine banks, instead of outside them. Exhaust gas recirc systems can be in weird places, too

* moving components which could easily dismember digits, deglove your hands, descalp you. Lots of cars have stuff that isn't moving, which can unexpectedly start moving (like electric cooling fans.)

* scalding hot fluids which could geyser if released (ie the coolant expansion tank)

* battery acid, used engine oil, etc

Hazards in an electric car engine compartment: none, if you don't cut through the insulation of the bright orange HV cables or drink the fluids.

"warning: do not wear shirt with tie while tensioning engine belts"

> which can unexpectedly start moving (like electric cooling fans.)

And where 'unexpectedly' includes: when the vehicle is stationary, and powered down, key removed from the ignition.

The big difference is that ICE compartments are a known measure, society has been dealing with them for almost a century so the "common sense" on it is well established (we know what mistakes an average stupid person will do and what mistakes an average smart person will do). But Electric is a whole new context, with a completely different set of safety rules, so it will take time to develop a new common sense compatible with those rules, until then there is a very big risk that people may incorrectly apply old safe common sense rules to the new context and get hurt.

It boils down to: "I have been [doing something] my entire life and it was always safe, then I got an EV, tried to do the exact same thing and got hurt". From the customer perspective the EV manufacturer turned a safe operation into an unsafe operation, so it is the manufacturer's fault.

> My car's gas engine does not consist exclusively of deadly high-voltage equipment in it that can kill me dead when my car is powered off, so I think it's fine to apply different safety processes to consumer-targeted electric cars than we apply to consumer-targeted gasoline cars.

Your car's gas engine, no. Your car's gas tank, however, absolutely can.

I bet Mercedes also has the audacity to prohibit me from prodding the gas tanks of their combustion cars with a screwdriver.

What happens when you prod a gas tank with a screwdriver?

I'll never know. :(

The right answer

You might damage the screwdriver I guess.

Probably not much. Fuel tanks are usually made of plastic now, so you aren't likely to create a spark and ignite something.

Petrol fuel in liquid form is hard to ignite, so if it leaks not much is going to happen other than giving your driveway a good clean (it's a solvent) - it's the gas form that is much more flammable. When petrol enters the engine combustion chamber it is mixed with air to form a flammable gas - there should be no liquid.

Diesel fuel is much harder to ignite, heck, you could probably use diesel fuel in place of engine oil and it probably wouldn't ignite.

Depending on the age of your vehicle, and how you hold the screwdriver anything from 'nothing' to 'foom'.

I can’t parse this objection. One of my failed attempts reads “My gasoline tank should have the same safety processes as electric cars”, which is obviously not a valid interpretation. My gas tank isn’t deadly for me to touch, so I’m quite lost if that’s what you meant instead.

Help me understand what you mean?

The parallel being drawn was that gas cars do not have components which can kill you when they are turned off: "it that can kill me dead when my car is powered off,", and so do not require stringent safety controls. My counter was that gas cars absolutely do have such components.

A 12V battery can kill you or seriously harm you. The entire chassis of the vehicle is the return path, and can make a short circuit or exposed wire exceptionally dangerous. Working around high current paths like the wire from the alternator can be a special hazard.

The battery can also release explosive gasses if charged or used improperly or if other parts of the electrical system are damaged. Combined with a spark and again death and serious injury are possible.

Pulleys and belts are under tension. It's probably not as lethal, but it's a stored energy hazard and has hurt plenty of technicians.

Suspension systems contain many stored energy hazards.

Tires with air pressure are a stored energy hazard, even if they're not attached to the vehicle.

> A 12V battery can kill you or seriously harm you.

How?

People wear metal jewelry and use metal tools. And dry skin resistance is not the same as wet skin resistance. Aside from these, admittedly, far fetched cases.. batteries can explode if serviced improperly.

Is filled with strong acids, for example.

But I agree that having to deal with high voltage is a totally new level of troubles.

You are vastly over estimating the hazards under a hood. When opening a hood and looking for a problem, filling up a water tank, checking oil or topping up the radiator the greatest danger is probably somehow not propping the food open correctly or forgetting to let it cool down first and touching a hot part or fluid and getting a minor burn.

Opening a car hood is miles less dangerous than changing a light bulb on a desktop lamp, it's probably even less dangerous than driving the car on the road.

>My counter was that gas cars absolutely do have such components.

They do? From your previous message I'm guessing you're referring to the gas tank. While it's technically true you can kill yourself with a gas tank, I don't think it's anywhere near the danger of electric car batteries. For a gas tank there's a clear sequence of events needed to cause injury/death. You need to either puncture it and then expose it to an ignition source, or throw an ignition source directly into the tank. The first is likely to be noticed because gasoline has a distinctive smell, and is physically visible. It's also surprisingly to light gas on fire[1] even if there is a leak. The second is so implausible to happen it's not even worth considering.

On the other hand, it's very easy for someone to touch the wrong wires under the hood of an electric car and get fried. There's no warning, you just get zapped. You might need to expose some wiring/connectors to get shocked, but there's nothing that tells you that this particular exposed wire is going to kill you.

[1] https://mythresults.com/special7 "It is possible to ignite a pool of gasoline using only a cigarette."

Typo: surprisingly ___ (difficult, I think it’s meant to say)

A modern fuel tank has two basic connections beyond sensors: fuel line and electrical supply for the fuel pump. When the pump isn't active, the only thing that comes out is a dribble of residual fuel from the fuel line. A full tank is not an intimidating thing on a motorcycle, where you're a lot more likely to remove it, it's not even that heavy.

I'd be more worried about crush injuries working underneath a car.

It's quite definitely not the same thing. I can't trespass on property I own. If I owned a substation, then it would be appropriate for it to warn "Danger! Risk of fatal electric shock!" but a "No trespassing" sign simply wouldn't apply to me and therefore provide no advice.

As others have said here, it would be far safer to warn owners of these cars "Danger! Risk of fatal electric shock! No user serviceable parts! Service must be done by a qualified engineer."

In fact without those warnings, I suspect that they would be legally liable, though IANAL, on the grounds that any reasonable person would know that "You must not open your own property" is not enforceable or reasonable, and when they do so, and die of electric shock, that is unexpected. "Risk of injury from moving parts" isn't going to put off anyone who has ever wrenched on a car, either.

> My car's gas engine does not consist exclusively of deadly high-voltage equipment in it that can kill me dead when my car is powered off, so I think it's fine to apply different safety processes to consumer-targeted electric cars than we apply to consumer-targeted gasoline cars.

You're making it sound like EVs are more dangerous than ICE vehicles, which they're not. Also, no other EV manufacturer has said or done anything like this.

It's still weird to me, as it's not uncommon for things to happen that you might want to check on. Like squirrels or other animals getting in there and building nests. Or allowing an owner to check on an odd noise that could be coming from the area, etc. A hood prop being absent seems dumb.