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Tesla shares 48V architecture with other automakers

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Re: Tesla shares 48V architecture with other automakers

#451

Post by bigallen »

lmpdev wrote: post #369
mmaunder wrote: post #246

Many comments here seem to be confusing the accessories circuit voltage with the electrical vehicle motor and drive system. The vehicle motors have a combined power output of 450KW which requires a high voltage 800V system or the wiring would be so heavy it would not be feasible. This spec appears to be the accessories circuit with Tesla pushing for a new 48V standard. That’s super smart because it immediately means…

I get this a lot I work at an electronics store in Australia This week I had a customer dumbfounded why his 3,500W inverter almost caught fire He was using 8-gauge wire (~56A max) He needed 00-gauge (almost 300A max) If he’d have run the system at 48V instead of 12V he’d have saved $200+ per metre on cabling his inverter My advice on voltage selection for a vehicle is once you’re needing more than a few metres of 0-g…

How do you integrate the 48V system with the existing 12V system when doing aftermarket/DIY work? Do you add a 48V inverter? A buck-boost DC-DC converter? between the battery (or main fuse block) and the 48V system?

Re: Tesla shares 48V architecture with other automakers

#452

Post by cashsterling »

mmaunder wrote: post #246

Many comments here seem to be confusing the accessories circuit voltage with the electrical vehicle motor and drive system. The vehicle motors have a combined power output of 450KW which requires a high voltage 800V system or the wiring would be so heavy it would not be feasible. This spec appears to be the accessories circuit with Tesla pushing for a new 48V standard. That’s super smart because it immediately means…

And FWIW... 24V is very common for DC circuits in industrial control systems. 48V is used too but less common; however, 48V is very common in telecom.

Re: Tesla shares 48V architecture with other automakers

#453

Post by hinkley »

CharlesW wrote: post #172
_ea1k wrote: post #161

Earlier quoted context omitted.

Tesla's greatest innovation is simply leadership. Everyone knew castings were the way to go, but noone did it. Now people like Volvo are doing them, and I expect a lot of others to do it as well. Everyone knew that 48V would be a big benefit, but noone did it. TBH, in a few years, we may be saying similar things about drive-by-wire without a mechanical backup. But it is too early to say definitively.

> Everyone knew castings were the way to go… The jury's still out on whether gigacasting is courageous, or just moves costs from production (which will not be passed to consumers) to repairs (which will). > Everyone knew that 48V would be a big benefit, but noone did it. Audi did in 2016 with the SQ7 TDI, no?

Clearly no MGB fans at Tesla. The unibody is cool unless you live somewhere with snow, and then rust doesn’t just make your car ugly, it makes it unsafe. And expensive to fix.

Which is why I was always more of a Triumph fan.

Re: Tesla shares 48V architecture with other automakers

#454

Post by 1970-01-01 »

stickfigure wrote: post #316
owengee wrote: post #301

Earlier quoted context omitted.

For batteries it tends to be multiple of the battery cell voltages. So 48v is probably so you could wire 4x12v batteries in series but that is a guess. With tool voltages this tends to be a multiple of the nominal battery voltage (rounded for marketing).

To riff on this, a lead-acid cell is 2.2v. If you look at the 12v battery in your (typical) car, it has six cells. It's less obvious with modern sealed batteries, but super obvious with flooded lead acid batteries in golf carts. Lithium batteries do not have 2.2v cells; typical li-ion cells are 3.7v. So there's no particular reason why you should stack them to 48v, except that there's already some amount of industria…

This is it, there are many ways to get there. The 48-volt architecture is achievable with four 12-volt lead acid batteries in series, or thirteen lithium-ion cells in series at their nominal 3.7-volts, or fifteen LiFePo4 cells in series at their nominal 3.2 volts. You can ask for any of these to manufacture a 48-volt vehicle.

Re: Tesla shares 48V architecture with other automakers

#455

Post by mcguire »

cogman10 wrote: post #129
mcguire wrote: post #81

Earlier quoted context omitted.

The rumor I heard was that the higher voltage resulted in lower switch lifetimes. Any truth to that?

Yes, but not meaningfully. The higher the voltage you get, the more arching there is when a relay trips (also depends on if there's any sort of inductive load, think the sparks you see when you unplug a vacuum without turning it off). But when you think about the impact that has on switches and relays, realize that in your own home you have 120V controlled by switches. Very cheap switches last decades (though admitte…

I thought about those, but the 120v AC switches are gigantic beefy things compared to most automotive switches.

Re: Tesla shares 48V architecture with other automakers

#456

Post by xenadu02 »

avalys wrote: post #397
DannyBee wrote: post #272

Earlier quoted context omitted.

48V has been considered for automotive for decades. The problem was not know how. It simply has never been worth it before to retool things in practice. It's also electrically a lot more noisy. The limit of what is considered low volt is like 60v or something.

Mercedes-Benz has been using 48V systems since 2016. https://paultan.org/2016/10/31/mercedes-benz-reveals-first-d... This dynamic, where Tesla "announces" something that the rest of the industry has been doing for a while anyway, and a bunch of star-struck enthusiasts and stock manipulators tout it as an example of Tesla' "super smart innovation", is getting tiresome.

There is still a large benefit to this. Because Tesla is seen as a leader in the EV space it prods others to follow them. In some cases like this it gives people in the supply chain or internally at other automakers justification to make changes they've been prevented from making in the past.

All sorts of people have all sorts of random ideas that never go anywhere until an industry "golden child" says it's the way forward. Without that effect the change can take much longer to happen.

Re: Tesla shares 48V architecture with other automakers

#458

Post by andrewf »

TheLoafOfBread wrote: post #363
andrewf wrote: post #355

Earlier quoted context omitted.

I think that's what 10BASE-T1S (standardized in 2019) is for. It has a non-CSMA/CD arbitration scheme. https://www.electronicspecifier.com/industries/industrial/an...

So... you need new PHYs and new Ethernet controllers to use T1S?

A lot of the Googleable information seems to be from chip vendors who want to sell those things :) Yeah it's intended for new designs. Fewer wires than the original 10mbps ethernet.

Re: Tesla shares 48V architecture with other automakers

#459

Post by hef19898 »

panick21_ wrote: post #450
hef19898 wrote: post #425

Earlier quoted context omitted.

A quick search turned up this: >> S&P Global Mobility forecasts 15% to 20% of traditional body-in-white (BIW) stampings in 2030 may be at risk from these gigacastings. Underbody components typically comprise about 50% of a vehicle's BIW shell, and this soft underbelly is the target of gigacasting's focus. Source: https://www.spglobal.com/mobility/en/research-analysis/gigac... Obviously not a technical journal, nor di…

You are underestimating how long things take in the car industry. 2030 is really, really soon. The majority of cars sold then will be existing models with minor updates. And car companies only upgrade their major platforms every 5-7 years. Many companies are currently planning their second (or first real) EV platform. But by 2030 even the waste number of EV will be on first generation EV platforms still. Companies ha…

I'm more an aerospace guy, but I am fully aware of the time scale around production technology changes. Thing is so, 2030 is an estimate, not a commitment. And I didn't find anything about actual investments or announcememts from OEMs around that.

Also, 20% of castings still means a lot of welding before a car body is made.

One thing regarding Toyotas production system so: it is all about management and processes and not about the actual machinery. And it share a lot of principles ranging as far back as Venice's Arsenal in the 16/17th century and, especially, WW2 mass manifavturing of, e.g., planes.

Anothet major difference: TPS is a proven methodology for longer than Tesla, let alone any production tech coming out of Tesla, exists as a company.

Re: Tesla shares 48V architecture with other automakers

#460

Post by grecy »

hef19898 wrote: post #419
grecy wrote: post #394

Earlier quoted context omitted.

The move to 48V means much less power is lost (power loss = (IxI)xR ), cables can be much smaller, cables and terminals can be much lighter and much less copper can be used used. Basically it's just a more efficient way of doing things. Elon has said it's not a revolution, or ground breaking in any way, it is simply a step improvement. Anyone could have done it. Tesla did it.

As others pointed out lready, others did it, too.

Re-read the comments, others have not done it.

Audi has a mild-hybrid 48V (as do many others) that also runs some other things like active roll control and the power steering pump.

They still have a 12v system running infotainment, seat heaters, defrosters, powered seats, lights, etc. etc.

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