Standardizing Automotive Connectivity
tesla.com
tesla.com
Using one kind of unkeyed connector in a car may be a bad idea. Things can be plugged in wrong during repairs. There's a lot to be said for making connectors not fit where they shouldn't. Especially in automotive, where many connectors are plugged in blind, by feel. This simplifies manufacturing at the cost of repair.
If it can be plugged in wrong, it will be plugged in wrong. AAA put a battery in backwards in my Jeep once, and most of the vehicle electronics had to be replaced.
There is also a J-shaped structure inside the plug that would function as a key as well, prevents the plug from starting when rotated 180 degrees.
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------Ideally a system like this would let you select some per-subsystem physical lockout mechanism.
Cars using whole bunch of different connectors relying on whole bunch of suppliers is feature-not-bug situation. It is optimal for large scale volume production; work will be more distributed, SPoF will be more localized, etc. Standardized connectors with trivial visual differences and/or field configurable keying is a suboptimal solution for car problem. Usually.
...is it a local minima for small scale production? Are they having issues with scale outs, and therefore seeking downward scalability?
That said, sometimes there are cases where an entirely new connector style isn’t warranted, and that’s where you use blanking pins or adjustable keyways or whatever.
You really couldn't control it at plug or part level.
The plug manufacturer has to provide many, many keying options (say for a 2-pin plug, one might have variants 2A, 2B, etc... which explicitly cannot mate with each other)
An engineer designing the car has to ensure all plugs with same keying options are interchangeable (2A is for power supply; 2B for door switch; etc...)
If the plug manufacturer does not provide enough keying options, this will be pretty hard to during design time.
Unless you are a big player, what plugs you are using boils down to what receptacle the component that you want to attach to use.
I tried to lower the window in a Ford shortly after leaving the dealer. It fried the lock. Somehow they were connected together by accident. I agree dumb wires should be hard to mix up like that - both via orientation and similarity.
Doesn't make things work when they are plugged into the wrong connector, but they should still work once the connections are straightened out.
If the Cybertrucks electrical ethos is followed by others there’s only 48V and Ethernet. Ethernet doesn’t care or fry if plugged into a wrong port. Any complex wiring can be done inside a part or component as needed, but the interface is one of a few options.
Let’s say the window motor is plugged into the power and not the switched motor plug. As long as it’s a 48V motor it’ll just turn but not fry. You just unplug it and reconnect it.
IMHO industrial everything should become 48V Ethernet. Just like for gadgets usb-c rules the roost.
I'm looking at the electrical schematic [1] and 'eth' appears 107 times while 'CAN' appears 805 times.
And if you think about it, you probably don't want your brake-by-wire system to share a bus with your sound system and your trunk latch for obvious reasons.
[1] https://service.tesla.com/docs/Cybertruck/ElectricalReferenc...
These two are still vulnerabilities with Ethernet.
Makes sense, though I’m a bit bummed.
> And if you think about it, you probably don't want your brake-by-wire system to share a bus with your sound system and your trunk latch for obvious reasons.
Sharing a bus for those two wouldn’t make sense. However Ethernet topology wouldn’t preclude having those on separate buses and linked via switches.
Though that’d pose problems with my view above about plugging anything in anywhere. Though it’s really more of a philosophical goal. ;)
The topology might not care, but someone designing a trunk latch that communicates via Ethernet might get a visit from an annoyed representative from Value Engineering.
Especially with the newer two wire ethernet with power via 10BASE-T1S. The connector likely costs more than the ethernet chip, and microprocessors can be had for nickels. So at large manufacturing scale it could easily cost less to share a single ethernet and power line and save on wiring, connector complexity, etc.
There's a high voltage (800V) rail for high current devices like the AC compressor. There's redundant CAN for communication with things like the motors. There's a host of 12V, 16V, 5V components (door locks, lights, seat motors, etc.).
They did switch many components to 48V, but not literally everything.
This will never take hold. These are extremely expensive vs weatherpack and other cheap connectors. Auto manufacturers care about literal pennies.
In the retail space, at least, DTM's largely been superseded by the lower-cost ATM line. Weatherpack and Metripack are pretty common in the US because GM developed them and GM is a huge company. The only company that comes to mind for using DTM connectors is Caterpillar, so you'll definitely see medium duty trucks with DTM assemblies.
The two automotive companies I'm most familiar with (80s Volvos and 00s BMWs) use keyed connectors all over the place. The Volvos used off-the-shelf washing machine connectors (AMP /(junior )+(power )+timer/) that can be had with keyed connectors. BMW saved pennies by going with high density connectors and small gauge wire. Most of that stuff is off-the-shelf as well, but often with proprietary keying.
Both DTM and Weather/MetriPack are pretty bulky compared to what's available now though, and when you're talking about 100 or 200 pin connectors size probably matters more than a few pennies. And, of course, once you start adding the retention doodads to MetriPack assemblies you start getting closer in price to DTM style stuff. The simplicity of the wedgelock design means fewer parts to stock and potentially faster assembly which could easily negate the more expensive housings.
And it's not even close. Just watch the teardown of Cybertruck and compare its wiring to something like F150.
What is ethernet bringing to the picture?
Over 3 orders of magnitude faster datarates.
CAN FD: up to 5Mb/s
Automotive Ethernet: up to 10 Gb/s
60 Hz * 3840 * 2160 * 14bit is 6.96 Gbps.
What you'll actually be sending is a high bitrate mpeg stream, probably 54Mbps or thereabouts, you could probably fit 50x camera streams on a shared 10Gbps bus.
My Chevy Volt had 4 different CAN buses and one additional LIN bus.
This can all be replaced with just two Ethernet buses: for safety-critical and non-critical uses. And the gigabit speed provides plenty of bandwidth for any reasonable sensor traffic, even including camera feeds.
The current architecture was justified in 90-s when LIN PHYs were an order of magnitude cheaper than even CAN PHYs. Now Gigabit Ethernet PHYs cost less than a dollar.
The "main" bus was saturated with data, more than 80% of bandwidth utilization at 512kbs. And it kinda had a mix of everything, from street names to be displayed on the dashboard to ECU messages. The other two buses had some random messages, with no rhyme or reason for the split ( https://vehicle-reverse-engineering.fandom.com/wiki/GM_Volt ).
More speed and zonal architecture:
* https://www.electronicdesign.com/markets/automotive/article/...
* https://www.bosch-mobility.com/en/solutions/control-units/zo...
Bandwidth: you can't ship backup camera video or entertainment system audio over CAN, for example.
CAN was meant for short, real-time packets. 8 bytes in initial configuration. CAN FD allows 64 byte packets.
You spend a LOT of protocol doing packet fragmentation and assembly using CAN--which then negates a lot of the real-time guarantees.
CAN should be used for the short safety critical stuff. Ethernet should be used for everything else.
10BASE-T1S is a new standard geared for automotive. It uses physical layer collision avoidance instead of classic Ethernet exponential backoff. This provides deterministic maximum latency.
Though you can get max latency guarantees with switched Ethernet and the appropriate switch QoS and hardware.
They can probably develop for a car ethernet lan with a desktop pc and car "peripherals".
Not that there aren't canbus cards for pcs, but still.
I can imagine a container to simulate each hardware unit, a small inter-contaner lan, and develop code that way.
I think the bigger factor is that innovation in the CAN ecosystem has been lagging behind Ethernet for decades now. Only reason it's had such staying power is industry inertia.
1. https://netmodule-linux.readthedocs.io/en/latest/howto/can.h...
For the record, 42V systems were experimented with in the 1990s:
* https://en.wikipedia.org/wiki/42-volt_electrical_system
In the 2011 German automakers agreed to 48V as the next step after 12V:
* https://en.wikipedia.org/wiki/48-volt_electrical_system
BMW was the first the first with Ethernet:
* https://www.marvell.com/blogs/the-right-stuff-a-past-and-fut...
I have no explanation for this.
Tooling all their shit to 48V is a massive undertaking with pretty much zero advantages.
You really need some special component that is much better at 48 for it to be worth it, otherwise a delayed platform switch is better; one some competitors have moved and the suppliers exist.
They _all_ benefit from 48V.
It's very, very hard to get insulation that's not good for at least 100V and I suspect that just about any generic wire is good for more like 300V.
The only exception that comes to mind is wire that's specifically for "household low voltage" like 24V AC for thermostat, doorbell, sprinklers, landscape lighting. Also normal ethernet. But these are almost all what you'd call signalling wiring rather than power wiring.
Your average hook-up wire that you could buy at the auto parts store to make some repairs is almost certainly rated for 300V already. Mostly because of chafe resistance. Wikipedia says that the dielectric breakdown strength of PVC is 40 millions volts per meter https://en.wikipedia.org/wiki/Polyvinyl_chloride.
Divide both sides by 1 million and you get 40 volts per micron. OK so you need 1/3 of a micron to insulate enough for 12V and you need 1.25 microns for 48V. Now let's have a reasonable safety factor of say 10 or so and we're looking at 3 microns vs 12.5 microns. The only wire I can think of that might have insulation that thin is enamel coated magnet wire for the inside of motor windings. But even that is probably thicker.
Any kind of plastic insulation is going to be significantly thicker than this just to be able to be coated onto the bare copper wire and stick.
You're not wrong that the insulation needs to be thicker as the voltage goes higher. But you're unaware of just how ridiculously over-insulated everything already is due to other constraints of manufacture.
The integrated starter generator(ISG) is usually a pancake shaped motor that replaces clutch/torque converter in ICE car, nothing like the regular starter motor.
MHV was not even real hybrid, and is no longer relevant, so was 48V, at least for a while.
Tesla didn't have any existing, so their clean-slate math was clearly in favor of 100% new technology.
(Well, they did have 12v existing in their other cars, but they were clean-slate in the truck.)
Major car components like doors or front axles are assembled in parallel to miscellaneous parts on the main body, and all .join() at the final assembly. This had been the case for past 30-50 years, possibly more, in case this needs to be said.
> Major car components like doors or front axles are assembled in parallel
And doors (and tailgates) are the biggest body component that is _sometimes_ assembled independently. Then workers manually route cables through the body.
Pre-routing cables inside panels that can then just be welded together can save a lot of labor.
Sometimes? What and when on Earth is this about? Pre-WWII?
They wash and paint and dry the whole body at once _for paint consistency_, then take off doors and trunk lids and bumpers and send them into separate assembly lines. Those major parts flow parallel "threads" in sync and converge near the end, where connectors are plugged in and those major parts are bolted back in and plastic trims are pushed in to tuck everything under. Cars were basically always done that way for a long time everywhere. I think even lots of hand made supercars are like that, only except tact times are magnitudes longer.
> Then workers manually route cables through the body.
> Pre-routing cables inside panels that can then just be welded together can save a lot of labor.
What do these even mean? Are you hallucinating workers crimping cables in-situ? They just clip on harnesses and plug in couplers in "the line". Never seen under a door trim?
It sounds like you're either extremely ill-informed, or worse yet, potentially, intentionally misinformed about car manufacturing that what you see is advanced manufacturing. I think you should... look more closely into what "legacy auto" have been doing forever.
Workers still need to pull the wiring bundles through the car body and clip them, after the body is welded together. The connectors are impractically bulky to put several of them along the cable routes.
Pre-assembled panels can have cable runs attached to them during the individual panel assembly.
I designed some stuff along these lines 15 years ago. At that time, 12 volt stuff was not just available, it was available with great economies of scale and a huge range of options, off the shelf. You need an automotive-qualified relay? A light? A solenoid? A DC-DC converter module? A fan? You'd have 100 choices at 12v, 30 choices at 24v and 3 choices at 48v.
The microcontroller still runs at 5/3.3/1.8 V.
BMW ENET is non-standard, DoIP is standard. :)
That said, it all seems like inside baseball to me. The BMW 850i pioneered the CAN bus, but that car was forgettable and although CAN bus took over the car industry that did not seem to create any durable advantages for BMW.
Ethernet seems like the inevitable replacement for CAN, in light of VW's investment in Rivian, and 48V vs. 12V for the low-voltage systems seems like a wash.
And some schooling. They shall learn about pokayoke.
Surely it isn't just that they reduced the number of connectors since one could have just standardized on a subset of mass-produced connectors by molex, te, etc. instead.
At least give us some comparisons!
I initially thought this was referring to the connector between the charge port on the EV and the charger base station. Had to think for a second and realized it’s the electrical connections between the various components in an EV.
Glad to know I don’t have to carry 200+ dongles in case I buy an EV.
the motorsports world generally has converged to exactly two connectors:
DT series connectors and AS series connectors. The former is made of plastic and very robust. The latter is made of metal and is extremely robust.
It's nice having to just have a bunch of DT parts and just be good to put it in everything.
This is not a standard in the sense that engineers use the term. Tesla is hoping it will be adopted as a standard and since Tesla doesn't appear to want to involve any standards bodies, Tesla appears to only be interested in making these connectors a de-facto standard.
In any case, that is not a standard.
edit: Inter to Intra.
(But no, I'm not liking that Tesla is taking the typical entitled-ass attitude of avoiding all the standards bodies, doing whatever they want, and expecting others to ratify their standard. If it is that good, it should be readily agreed to by the relevant standards bodies.)
This exists: https://news.ycombinator.com/item?id=41975736 But for Lucid, not Teslas. And also more generally as a use of V2L.
> in-the-field recharge for cars that run out before the recharging station
This exists: https://www.fleetnews.co.uk/news/latest-news/2023/06/30/elec... https://www.taxi-point.co.uk/post/rac-to-equip-breakdown-van...
> a range-extending spare battery pack
This is a real Tesla Cybertruck accessory: https://insideevs.com/news/706702/tesla-cybertruck-range-ext...
Sounds like jumper cables.
But no, I don't think Tesla is doing those.
But it does seem that Tesla is planning to do those some time:
https://cleantechnica.com/2023/08/19/tesla-plans-to-adopt-bi...
https://thedriven.io/2024/05/06/teslas-take-on-v2g-controlli...
While describing stuff that exists in some form, and usually has existed for years already now.
It's not evenly distributed new tech for sure (1). But maybe it's the false assumption that "if it was anywhere, I'd be among the ones to see it early".
1) See William Gibson: "The Future is Already Here, it's Just Not Very Evenly Distributed."
That's entirely possible at present. Many electric vehicles can send power out to power appliances. It's called "Vehicle to Load" or "V2L".
And electric vehicles can slow-charge off a wall power socket, so they could get that from V2L. It won't be a common use, but it would work in a pinch to get you enough juice to get to a better charger?
<10kw, so not super fast, but I bet most people are really close to the charging station when they run out.
https://www.tesla.com/legal/additional-resources#patent-pled...
A party is "acting in good faith" for so long as such party and its related or affiliated companies have not:
asserted, helped others assert or had a financial stake in any assertion of
(i) any patent or other intellectual property right against Tesla or
(ii) any patent right against a third party for its use of technologies relating to electric vehicles or related equipment;
So, if another company rips off your IP but Tesla doesn't think it is a "knock-off product", you sue that other company, you're now in violation of Tesla's "patent pledge". Its an attempt to use a carrot of Tesla's patents to make all the other rightsholders essentially give up all their IP. If you sue anyone protecting your EV IP, you're in violation of this agreement and will be open to litigation by Tesla.
I think we should give Tesla the benefit of the doubt for now. Harmful use of patents could cause issues, but this has potential. We will simply see if other companies are interested, and if they are it can go from internal standard to de facto standard to formalized standard.
They are doing what they need done for their business and then inviting others to join. And way earlier than they did with NACS: https://www.tesla.com/blog/opening-north-american-charging-s...
> As NACS is now recognized in a SAE recommended practice (RP) under SAE J3400, we have removed the technical specifications and CAD from our website.
So something that was previously freely available now requires a $300 payment to access.
I'm sad to see that.
It likely is still freely shareable for existing copies.
what a ridiculous counterfactual. We have plenty of wildly successful standards that weren't just thrown at consumers and called a standard.
all of the USB connectors including USB-C, with it mandate to support so many different edge cases that cause cables to not always be compatible with each other defeating the purpose.
Bluetooth again with so many edge cases that made it terrible until Apple came along and cut a lot of that out in their solution finally made it tolerable.
Hell even a lot of electrical connectors (such as the US outlet) suck: developed in that way due to historical interests, it looks terrible, is not entirely safe (ie. ground does not go in first) and now has stuff bolted on to make up for its shortfalls. (GFCI, in line fuses etc.)
Now there are probably loads of terrible proprietary connectors but it seems like the free market eventually takes care of disposing of the chaff. That itself is a forcing function to get to a better design that users will like. Whereas you have no choice of a standardized connector because some "standards body" made up of opposing interests artificially keeps lousy designs around and forces it upon the population.
Im not arguing for one or the other but its just annoying that standards bodies always seem to get a pass when in my experience they produce a lot of mediocre stuff.
Adding a standards body into the mix is going to add complexity to the process by definition, but shouldn't be taken as a default "bad", since there are tangible benefits to non-corporation-managed standards. Otherwise they wouldn't exist.
BGP, 802.11, QUIC, HTTP, SSH all came from dominating implementations.
What is a "standard" then? Does it need to have an ISO seal?
The goal seems to be to promote reuse of a good-enough design in as many places as possible. Noone's forced to use it, but it'd make things simpler for everyone if there is as much commonality as possible.
Is there a reason why 48V is better long term than going higher like 96V?
Too big/bulky?
The connector is bulky and of metal, and designed to be used inside. It's also expensive compared to other connectors. There are a lot of cheaper, more suitable connectors, designed to carry power.
IMO solar pioneered (in recent history) 48V DC systems, which is an easy multiple of 12V to stay below the 50V “high voltage” safety threshold.
It allowed people to use smaller gauge wire and chain together multiple 12V batteries that are readily available.
Signaling on POTS easily hit over 100V, btw.
A short/failure at 100V is much more dangerous than at 50V. Both from a fire-safety perspective as well as an electrocution risk perspective.
One another advantage of the new 48V architecture is that it doesn't depend on the car body for the current return path. This opens up possibilities of adding sensors that detect current leakage, to pinpoint areas with defective wiring and/or components.
Is this tongue-in-cheek, or is there a reason manufacturers care about the color?
Light blue is used for 48V.
Ideally you should be able to differentiate high voltage (orange, iirc), safety (yellow), mid voltage, and everything else.
Also, speeding up the adoption of 48V, the industry has been talking about it for so long!
Tesla is so far ahead when it comes to these things (48V architecture), there literally is no other source in this case.
The other reality is that all of the Chinese OEMs will generally work with the companies like Molex, TE, Amphenol, etc just long enough to let them shoulder the R&D cost and then reverse engineer and vertically integrate the part in their supply chain.
If there is a chance to leverage their scale and supply chain to compete where there is known demand, it’s worth it to be early in and then be able to help OEMs customize the reference designs as needed.
Usually they create their own design so maybe having an open standard would allow you to do contract orders with any plastic injector that has the molds.
XKCD summed this up pretty well: https://xkcd.com/927/
Besides that, I have no respect for Tesla. They can't engineer their way out of a paper bag, they are hostile to both the customer and the rest of the industry, and notoriously so in terms of repairability--why would I believe that now they suddenly care about designing a better, more universal connector? They don't even make repair parts available to the consumer!
For those reasons and many more, the absolute LAST thing I would ever do as an engineer is to buy into a standard set by Tesla, or any other company run by Elon Musk.
china has the most electric cars, the largest manufacturers, and the most advanced battery production on the planet. their experience with electric vehicles and charging would be a valuable leap forward.
As for China having the most electric cars on the planet. I don't feel that makes them the experts. China tends to steal / copy technology from other countries and has little innovation them self from my view point. They have the most EV's from heavy government subsidies. Tons of cars in graveyards over there.