Terry seems like a great Man. Well spoken, smart, and a natural teacher. I enjoy both he, and Sandy.

Really happy to hear him mention mechanical fatigue in small wire. Size appropriately.

When I worked for GM, getting the hundreds of wires passed through the "forward bulkhead" (we were not allowed to call it the firewall) was a major headache and a recurring quality problem causing leaks. I was on the task team to come up with solutions, which were just bandaids in the end. As shown in this video, the trick Tesla is using would solve or avoid problems for any vehicle, but especially for ICE vehicles, where the engine compartment is more exposed to water.

Having engineered in auto wiring harness world wide for 44 years I can see one of the biggest benefits of reducing conductor sizes is a reduction in the exponential mechanical failure of harnesses and connectors due to the leverage exerted between large diameter wires and their comparatively flexible insulator connector housings (inevitably plastic). Some of the luxury vehicle wiring harnesses are so big /heavy they take 2 people to lift them and tooling / cost for larger crimped terminal ends again is an exponential rise in difficulty / cost / weight / size.........Go Tesla 48v

I'm a retired electronic engineer. If someone had come to me 20 years ago and asked me to design the entire electrical system for a car starting from a blank slate, I would've said : 48Vdc; zonal architecture; software defined; Ethernet and power on the same wires; and steer by wire. Am I some sort of genius? No, definitely not. But I think most competent system designers in that era would've come up with the same list. Tesla deserves a lot of credit for finally doing what should've been done long ago, but I can't say any of it is ingenious. At least not from what I've seen so far.

Gotta love good engineering.

Really first class presentation! Calm, educational, professional! Stay with Caresoft John!

At 23:00 where he's talking about stepping down, note that there aren't actually any transformers unless isolation is needed (which isn't typical for most of the DC-DC conversions inside a vehicle). Transformers are mostly used for AC circuitry, not DC. Those are inductors and the actual DC-DC conversion is called a "buck converter". There isn't really much to it. It is literally just a controller, an inductor, a capacitor, and a FET. And the FET is often built into the controller chip. The size of the components depends on the amount of current the DC-DC converter needs to handle and the switching frequency. The more current you need to handle, the larger the components and the lower the switching frequency. The less current you need to handle, the smaller the components and the higher the switch frequency. Higher switching frequencies also allow components to be downsized so its a double advantage. These buck converters can be the size of your thumb up to around the size of your hand. For example, a typical USB-C buck converter (USB-C can deliver different voltages to the equipment)... that's the size of your thumb and can deliver up to around 60W. The size of two fingers can deliver up to around 100W. (XXX this is wrong XXX) The reason an array of capacitors is used there is to reduce ESR (equivalent series resistance). The reason this is needed is because they are using cheap ceramic SMT capacitors. Ceramic SMT capacitors have severe ESR issues. To get around those issues the buck converter controller usually has to have a high switching speed, between 1 MHz and 10 MHz. A second axis on reducing the problems is to use an array of ceramic SMT capacitors in parallel (reducing the ESR). Ceramic SMTs are preferred because as long as you can control the ESR, they basically don't fail. Unlike other types of capacitors such as electrolytics. (correction) Not ESR, capacitance at higher voltages. Ceramics lose a great deal of capacitance at higher voltages. The ESR is quite good. As is life-span. -Matt

You may not like the vehicle but you gotta respect the technology and intelligence that went into building it. Imagine how much copper and weight Ford would save if they did this to the F150?!?!

Terry Woychowski is like the Bob Ross of the automotive industry.

The Tesla haters are always really quiet on these types of video. Great content Autoline!

I expect the Chinese EV makers to adapt a lot of this technology in their EV's to reduce the weight and cost even more before the legacy automakers. Someone posted on X, "Americans innovate, Chinese replicate and Europe regulates!"

Another great video! Thanks Caresoft and Autoline. I can’t get enough!

Thanks John, Terry, and Caresoft for sharing this info on the Cybertruck low voltage system. Much appreciated.

General Motors looked at 40+volt systems at about the 1990's, when I was there. We had done many military vehicles for decades before, at the 36-38volt ranges for the same reasons. However, by the 90's, we had transitioned to electric turret drives, and it was realized early that these systems were not adequate, so we transitioned to 150-160volt systems. Those could be recharged from ordinary 115-120volt power sources, which were commonly available in military world. When GM engineering generally became aware of these higher-voltage systems, it kicked off a series of EV designs, using such voltages and power levels. However, at that time, the manufacturing plants for lead-acid batteries had pretty much agreed to a common "sizing" architecture for the 12volts, and the shift to 40+V would have required either one-half plate widths (with resultant loss of lifetime), or a double-to-triple sized battery set. Just the weight of the batteries would have offset any significant weight savings from copper reduction, and the production costs would have actually raised the cost of manufacture of the vehicle. Other vendors of items such as Lamps also objected, since the filaments would be too weak to make any customer sense, since replacements would be required every couple of months. It was not until you actually had a technological transition to LCDs, LEDs, which eliminated the old filament lamps, and also the evolution of Lithium batteries, whereby very thin plates and small packages could be made, that the actual shift to higher voltage systems could be made. Televisions and computer monitors drove a lot of this evolution, and later smart-phones forced a complete shift to electronic "smart systems" where 0.2-cent IC chips could mate to any prime power source below about 80volts. With the original alternators on cars, the "load-dump" voltages were capped at about 70-to-80volts at the alternator, so an evolution to a system below that was a natural. The 30-to-40volt range is limited by a "safety factor" due to the work functions of materials, and human safety. Above that range, continuous arcing and welding can occur, which can result in spontaneous and continuous combustion of the wiring and metallic structures. Any customer or service personnel accessible batteries need to be below this range, for human safety, or otherwise they will have to be totally contained, and only serviceable by special tooling. Paschen limits are already being violated by the 400-to-800volt systems, and these vehicles, and their chargers will have accelerated failure rates. The future tradeoffs for this technology are being explored and developed as we speak. I suspect we will learn a lot more, very soon.

So there is a 3rd reason they didn’t reduce the wire size for the battery cooling loop, they may be planning on using the same loop for the “Range Extender”. Or they may be considering the truck may need more cooling

Looks like Bosch is on board with this change to 48 volt. That is a big vote of confidence for Tesla’s system.

Thanks for the video, please keep interviewing the professor about more things, I love watching and learning from him

Love this entire series of videos. Terry is so well spoken. It's clear he not only knows what he's talking about but you can see how enthusiastic he is about the technology. Hope these continue.

48 VDC is what the POTS plain-old-telephone-system uses. At your local telephone exchange office there is a huge 48 volt lead acid battery weighing 3000 pounds. It can hold up the telephone system for days without recharging. It is an extremely clean DC current source. To local telephone(s) the wires can only flow a very small amount of current. Off-hook the telephone line is loaded causing the voltage to fall to much lower. I'd like to known how 48 VDC systems are dealing with physical switch contact arching that is an issue above 24 VDC. The major issue for DC voltages above 24 volts (28 volts effective with two 12 volt lead acid batteries) is direct current arching with common switch contacts. Alternating currents have a huge advantage when it comes to switching with physical contacts over higher voltage direct current because the alternating current goes to zero volts cutting off arcing unless the gases have ionized in to a conduction medium. DC currents will continue to arc much longer. They can fuse a relays contacts together at relatively low voltages where there would be no problem for the same average AC voltage which actually has a much higher peak voltage. Common switches with physical contacts are rated at 125 VAC and only 24 VDC.

Wow, I thought this channel hated Tesla? Nice to see something positive. Tesla should be able to take credit sometimes, they have brought so many firsts. The EV market was dire before they transformed it and single-handedly ignited interest in the market.

superb presentation. i enjoy these teardowns. surprised to hear legacy too risk averse to improve. this is what competition does.

Thank you Autoline for content while your team is on break. John, very minor thing, you need to bring an Autoline vest or shirt so you do not like you work at the company you are visiting (😊), more important is when people want share this video your Autoline branding will in the video. Just a thought. Keep up the great work.

At Tesla the engineers run the company. NOT the accountants. It shows in their agility and everything they do. Guess what type of people run Boeing?

24:36 More important that component suppliers like Bosch (did I saw Bosch wipers motors?) start building 48V versions of their components used by the car manufacturers. Having Telas already as a customer for some of the components makes it easier to start.

The comparison is fantastic; just want to know an interesting features, how they raise 400V to 800V while charging a 400V Charging Station. For example, while Hyundai, BYD, and other OEMs use existing components (Emotor winding for boosting), Cyber Truck achieves this function with the use of additional electronics. Show us this additional stuff and how they incorporated it into the penthouse, cost and so on.

Thank you , at last someone explained to us non technicals how 48 volt reduces the amount of copper.

I just really hope this winds up in the M-Y refresh. I don't expect it but Ican dream

Excellent explanations of the 48V system.

I love seeing John's enthusiasm still, he's always excited for tech and manufacturing efficiency / improvements.

This is one of the most informative and well-done videos I've seen on this most important topic! Thank you. If I had had Terry as a professor (and I did have excellent professors), I might have continued my graduate education in EE (instead of statistics, IT, and cognitive psychology). But as the wheel turns, all these subjects and disciplines come back together again (first principles, etc.). It is an exciting lime to be alive!

Like Elon or not, he's changed the vehicle industry for a lifetime. Going against the grain to do the obvious is why I love Elon.

What is interesting is that on the "old" 12V systrem, The RADIO or HEAD UNITS or power amplifier had to use a BOOST converter to multiply the voltage in order to get the desirated amplifier output level.. BUT with 48V system.. you no more need that!! even the RAIL of 48V is enough to work in half bridge and supply 1000W to the speakers!

Terry gives a great lecture. John is the student representing the worldwide class. Close-ups really appreciated. I hope Terry pays well for this sponsored really important news for mankind and our use of worldwide resources. I expect Terry has a string of customers paying him well. All very well for Elon to circulate his document to the industry, but it is people like Terry who can advise the actual components Tesla use and who supplies them. And Terry tears down other vehicles too. Great to see his summary of recent Chinese vehicles. Innovation in China is quickly made known to other makers around the world. Patents ensure inventors get paid to innovation others want to use. The innovation industry functions well.

Informative video thanks. I do need to point out that B) on the whiteboard is inaccurate though. Power = V*I but Energy = V*I*time. 2 completely different things.

It should be noted that 48V has been in general use as a standard for decades, just not in Autos, and nearly all the technological components already existed... particularly power over ethernet (POE) which has been around for a very long time. It was very easy to implement because the data lines for ethernet are capacitively coupled, which means you can piggy-back a DC level (aka power) on the same wires. The current standard is called POE+ and is defined as a 48V standard that can transmit around 15W per twisted pair. A standard gigabit ethernet cable contains 4 pairs, so 60W can be transmitted. There is also a higher-voltage and current industrial standard that can transmit significamtly more power. The twisted pair for ethernet is 23 to 26 AWG (roughly). Terry did a good job describing the advantages but missed one of the most important advantages... losses over wiring go by the SQUARE of the current. P = I * I * R . So transmitting the same amount of power over the same gauge wire at 48V has 1/16th the wiring losses verses 12V. And because of that, thinner wire can be used and EVEN WITH the thinner wire, power losses over the wiring at 48V will STILL be 1/8th the wiring losses verses 12V for carrying the same amount of power. -Matt

When you eliminate the cost of a paint line you make room in the budget for 48 volt systems. If you work for a traditional auto company and you move to a 48v system and eliminate the paint line you save even more money by loosing your job.

The e-bike industry is making similar design decisions, with 48V DC being the current sweet spot.

high-energy components like the active suspension on the Ferrari Purosangue make a huge difference. POWAH!

What an amazing vehicle! It really is the greatest vehicle ever built.

13:11 it is crazy to see ~24A of current flowing through these wire, gotta be some magic happening.

Go back and watch Munro's interview with the 5 engineers and you will learn why they didn't go the whole way, in this truck they tackled the highest loads

Does Caresoft do open houses? I’d love to attend.

According to my information, Cybertruck is not uni-body. They abandoned the idea due to complicated construction.

Thank you guys. Looking forward to see the fruits of all these techs... Like the long awaited affordable model.

Thank you both for this great video.

Very educational, great many thanks. Love learning some things new everyday

5:40 - A Texas Model Y to be specific. Tesla makes like three differrnt versions of the Model Y...

For an idea of where Tesla is going with this evolution in electrical architecture design, and why they can pull it off: kzfaq.info/get/bejne/aZ54kpuS2Kq5lo0.html Cybertruck is just "Etherloop" version 1, and we have a pretty good idea already of where it's headed from their recent engineering slides and product roadmaps.

It's interesting to see that even with the Model Y, Tesla is doing its best by running 15V instead of 12V.

Thank you for great lesson, Professor Xavier!

Thank you for the education.

I wonder about insulation rub through yielding shorts to ground with higher voltage able to jump a spark gap that 12v would not. Not to mention in high corrosion conditions.

Great presentation. Thank you!

I love the fact that Elon was able to instil the required culture throughout the company. First principles thinking, innovative thinking and humour. I’m a forever fan.

Side info. Military wheeled vehicles run off of series parallel batteries running 24v and 12v. LMTV HMMWV FMTV Armoured Knight.

*Excellent!* Loved seeing this stuff.

To do the solution in different ways is for safety. One should always work following Iso 26262.

who wants a better mousetrap? "not me" said the big three...

Quick question, did you have a falling out with Sandy Munro?

Funny you should mention the wiper motor. There is currently a recall open on the wiper motor for the motors failing. Over on his channel, Munro praised the wiper motor for being small because it runs on 48 Volts. Commenters were quick to point out thar the physical size the motor is not necessarily related to operating voltage.

Do they talk about increased energy efficiency or reduction in heat losses because of this switch to 48V? Heat loss = Current^2 x Resistance. Therefore, assuming that the resistance remains the same, the current becomes four times less (because of the voltage going up from 12V to 48V), the heat loss will come down to 1/16th!

Missed the important reason that a low voltage system is needed. High voltage would be dangerous to use in all the peripheral devices. Why 48V, because it is about as high as you can go and still have a 'safe' low voltage.

The host, John, is a smart man and a great host.

Sounds nice, I bet it will be great once they get all the problems ironed out

I'm still wondering why Tesla doesn't use data over power cables and shared ground. That way they could have only one 48 V shared wire for everything and use Powerline ethernet data connections over that wire. Smaller manufacturer couldn't do this because you need lots of devices to make it sensible to produce enough controllers so that cost per controller for the data adapter gets low enough thanks to mass manufacturing.

Those tesla water pumps are awesome.

What a great prof!

I brainstorm about converting Cybertruck to the RV. Do you think it is good idea to drive all house appliances from that 48V battery? Most significant appliance is fridge with 150 W and some smaller and peaked. How to integrate photovoltaics? Dirty way is mppt controller, small battery driving appliances and when full step up inverter for onboard charger. Can this be done more effectively but safely?

My gf says Terry has a really pleasant voice. She's a singer and I don't understand but seemed an interesting comment.

Really informative! 👏👏👏 I wish they do the same from now on in their future vehicles 👍👍👍

12:45 it's not "work to be done", they almost certainly sized the CT wire to be able to run much higher average power to the coolant pump in order to get a much higher sustained battery and motor power. Marketing the truck as "faster than a porsche while towing a porsche" then having it throttle to 60 MPH when actually towing in hot weather would be a PR desaster.

That ultra small wire may not burn out, but it surely will break from normal road vibrations and flexing....given today's expanded sensor numbers, the likely chance of that setting you up for expensive tow and repair bills is greatly expanded....

How fragile are the new wires?

how come the coolant pump has more watts & more amps on Model Y than the blower motor, but a much smaller cable cross-section? (1mm2 for coolant pump, 4mm2 for blower motor) Both should be off 12V network. Anyone has an explanation for that? Only difference I can think of is cable length, but the difference in cross section seems to be huge .... 1mm2 for up to 24Amps just seems excessive, even for short cable lengths...

Guys please use U for Voltage as a symbol! V is the unit!

less heating in the motors, lower current spikes - great for motor driver components, better pwm, not having to deal with high current is great

large semi already has 24v for as long as they exist btw

I would love to see a deep dive on the Cybertruck’s ethernet.

I enjoy this guys views on things. I unsubbed Sandy because he’s insufferable and is not impartial.

long overdue

21:00 seems designed so a Tesla Bot can do it.

Every time you have Woychowski on he talks so quietly I have to boost my Windows volume to twice what any other YT content requires. Just boost his mic in post, c'mon.

making boards the "lightiest" way! 3:)

Most don't understand that 48v has been widely used for at least 20 years in the computer industry. PoE is a standard. Switching to 48v opens them up to more suppliers.

So how much of this is simply a result of Tesla solving for a Tesla-specific design problem? My 25 year old EVs use much smaller wiring than what you showed for the Model Y, and in fact, their 12 V wiring from the main DC-DC converter appears to be a similar size to the Cybertruck's 48 V DC-DC wire. Is that because my 25 year old EVs ran the cables for all the non-essential, heavy load components directly off the 300 V system's HV junction box? In combination with the floor for the low-load wiring size being 0.35 mm2, it seems like there are very few areas of actual improvement that justify a switch to 48 V, especially when LV safety issues are also considered.

Outstanding presentation!!! Non engineers like myself find this material fascinating.

10:24 - now pay special attention to this point boys and girls regarding what he states about there being LIMITS.

I appreciate that Tesla takes the risks to change things. They might not be inventing something totally new, but they are showing legacy builders have been stuck due to company culture, profits now no consideration for rhe future benefits thinking, no appetite for risk, and so on. I know Musk rubs many people the wrong way, but his personality has made taking big risks okay. Tesla is successful for manyvreasons, but adding in the willingness to gamble on developing tech that might fail really helps.

Why such a big jump? 24 volt technology is well tested on trucks and small aircraft. When you switch voltages it's the little stuff that can bite you.

And 48Vdc is below the safety threshold of 60Vdc.

Architected? How about designed?

The fail fast model Elon follows has proven to be far superior in all ways. A lot of people hate him for it , without knowing he's designing the future

So Tesla can’t build a car still? Or will we shut up about that finally?

Why not 96V?!

If you're running out of power for all the modules, maybe you have way too many. My POV there should only be four: engine, transmission, brakes/stability/traction, and spyware/infotainment/misc.

23:50 They missed the other easter egg "Mind the Gap" It's sexual reference on a woman

Speak up! Up the volume, please.

👏👏

The Coolant pump data is bullshit, 24amps RMS through 1 square millimetre would be unreliable. The pump is brushless and is communtated at the BCM, 24 amps is likely the peak current on 1 phase.