Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Tesla shares 48V architecture with other automakers

electrek.co

Post reply on HN
Print view View original

391–400 of 504 posts

Re: Tesla shares 48V architecture with other automakers

#391

Post by maxerickson »

grecy wrote: post #274
maxerickson wrote: post #260

Earlier quoted context omitted.

Realistically, using 12 volt and 48 volt for accessory systems are pretty similar. 48 volts just reduces your current, and you have to design everything for ~56 volts instead of ~14. But it's not really a different exercise.

> 48 volts just reduces your current "Just" is doing an awful lot of work in that sentence. Yes, moving from 12v to 48v reduces the current. That means you can have much smaller gauge wires, it means you lose a lot less power ( powerloss = (I I) R ), it means you use a lot less copper and it means you save a lot of weight on wiring and connectors. That is literally the point.

Right, the reason to do it is obvious and the development work is straightforward, it's a step forward but it isn't something to get all breathless about.

Re: Tesla shares 48V architecture with other automakers

#392

Post by arcticbull »

ipaddr wrote: post #343
arcticbull wrote: post #193

Earlier quoted context omitted.

> The labels we give to others to divide us Labels are an optimisation, an imperfect shortcut. They are a way we represent ourselves to others. If you don't tell me you're an engineer, I have to ask a ton of questions to assess your area of competence and skill. If you tell me you're an engineer I can save minutes or hours by putting you in a rough box. If that box is unnecessarily constraining it'll become clear as…

When race, gender, sexuality are involved we agree that labeling to save time isn't something accepted. For all of the reasons why shouldn't label those groups applies other labeling.

Most agree that we shouldn't actively do it, but we definitely do it consciously and subconsciously. It's a very human trait, even if we don't like it. The brain just doesn't have the capacity to evaluate everyone from scratch every time, so it takes shortcuts, and 'accepts' people based on the way they present themselves. The kinds of clothes they wear, shoes they're wearing, and accreditation from mutually trusted institutions. I agree the shortcuts that cause harm should be curbed to the best of our abilities but we can at best notice it and correct after the fact - but it'll still happen.

Re: Tesla shares 48V architecture with other automakers

#393

Post by mpreda »

hef19898 wrote: post #378
grecy wrote: post #374

Earlier quoted context omitted.

> but there are probably reasons it hasn’t already changed everywhere else Yes, the legacy OEMs are constrained by their suppliers, who dictate what they can (not) do.

In automotive, it is usually the other way round. Regardless, what exactly was wrong with the existing 12 and 24 V systems for auxiliaries that absolutely needed to be changed?

High current (amperage) requiring thicker wires, or more wires, thicker/heavier connections, more expensive switches, more cooling etc.

Re: Tesla shares 48V architecture with other automakers

#394

Post by grecy »

hef19898 wrote: post #378
grecy wrote: post #374

Earlier quoted context omitted.

> but there are probably reasons it hasn’t already changed everywhere else Yes, the legacy OEMs are constrained by their suppliers, who dictate what they can (not) do.

In automotive, it is usually the other way round. Regardless, what exactly was wrong with the existing 12 and 24 V systems for auxiliaries that absolutely needed to be changed?

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.

Re: Tesla shares 48V architecture with other automakers

#395

Post by grecy »

hinkley wrote: post #380
grecy wrote: post #225

Earlier quoted context omitted.

> The EV and hybrid electric world were talking about 48 volts when Musk still worked at PayPal, if not earlier. You are confounding the two electrical systems in an EV or hybrid (or mild hybrid). One is used to drive the wheels - these are very commonly 48V in a mild hybrid and something like 200V or 400V or 800V in an EV. This is only used to power the wheels - nothing else. The other electrical system is used to p…

I’m talking about the same thing. Pumps and compressors and electronics systems.

You're talking about some of the things that would be on the accessory belt (serpentine belt) on an ICE, that need to keep spinning even when the ICE is off (power steering, A/C, etc.). That is a slightly more fancy engine start/stop.

You are not talking about high current devices like heated and cooled seats, defrosters, infotainment and audio amps, power windows, power seats, lights, etc. etc.

Re: Tesla shares 48V architecture with other automakers

#396

Post by grecy »

maxerickson wrote: post #391
grecy wrote: post #274

Earlier quoted context omitted.

> 48 volts just reduces your current "Just" is doing an awful lot of work in that sentence. Yes, moving from 12v to 48v reduces the current. That means you can have much smaller gauge wires, it means you lose a lot less power ( powerloss = (I I) R ), it means you use a lot less copper and it means you save a lot of weight on wiring and connectors. That is literally the point.

Right, the reason to do it is obvious and the development work is straightforward, it's a step forward but it isn't something to get all breathless about.

Absolutely, Elon said that himself in the recent Munroe interview.

It is just bringing car wiring into the 21st century.

Re: Tesla shares 48V architecture with other automakers

#397

Post by avalys »

DannyBee wrote: post #272
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…

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.

Re: Tesla shares 48V architecture with other automakers

#399

Post by Closi »

hef19898 wrote: post #353
jdewerd wrote: post #338

Earlier quoted context omitted.

It was never worth it to retool for decades ? Or was there a pathological lock-in between suppliers and manufacturers that prevented even the most obvious innovations from happening if they required any amount of coordination?

Since car manufacturing, and design, wasn't held back at all by something like auxiliary current, the reason more likely was people not wanting to waste energy to improve on something that is working just fine for everyone.

Well according to Tesla it wasn't working just fine for everyone - they have been able to massively simplify their internal wiring.

Classic example of legacy automakers happy to maintain the status-quo because it is easiest, while the new kid on the block is pointing out that things don't have to be the way they are just because they are that way.

Re: Tesla shares 48V architecture with other automakers

#400

Post by sejl »

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…

I guess you work at Jaycar too? Always a fun conversation trying to explain voltage drop to someone who wants to cheap out on cable with our inverters and DC/DC chargers.

I'm sure a 48V bus would solve all those F1 errors too.

Post reply on HN