is tesla forced to do so because the other automakers are clueless?
Tesla shares 48V architecture with other automakers
371–380 of 504 posts
Re: Tesla shares 48V architecture with other automakers
#372Earlier quoted context omitted.
> This is an older article but explains it well https://www.greencarcongress.com/2017/06/20170602-audi.html From the article: > The 12-volt system is connected to the main electrical system via a DC/DC converter > Audi also offers the new MHEV technology with the conventional 12-volt electrical system > 48-volt vehicle electrical system. In a different layout—without MHEV—the 48-volt constant voltage system already e…
At least in the case of Audi it is more than just the starter used for the mild hybrid depending on market and configuration. On my generation/configuration of car it is also used to prespin the Turbo to avoid lag, it powers the active magnetic suspension, the AC compressor, and the power steering pump (annoyingly located between the feet of the driver and the seat where you can feel it when it runs). While you’re ri…
Sure, they use the 48v mild hybrid system to act like the ICE when the ice is not running to power some things that would be on the serpentine belt and need to keep spinning when the ICE is off. It's a slightly more fancy engine start/stop system.
> the tech exists within car companies
Of course. Elon said very clearly in the sandy munroe interview the move to 48v everything is nothing revolutionary, its just bringing vehicle wiring into the 21st century. Anyone could have done it, they just have not been able to pull it off before now.
> They have a 12v only model that shares parts and they apparently didn’t want to move everything to 48.
They couldn't move everything to 48v because their suppliers dictate what they can do, and that prevented them.
Re: Tesla shares 48V architecture with other automakers
#373Many 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…
Given the choice almost any EE would probably pick the higher voltage system for cost saving reasons, but I imagine they were mostly constrained by legacy compatibility requirements here.
It’a “smart”, but there are probably reasons it hasn’t already changed everywhere else.
Re: Tesla shares 48V architecture with other automakers
#374Many 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…
Given the choice almost any EE would probably pick the higher voltage system for cost saving reasons, but I imagine they were mostly constrained by legacy compatibility requirements here. It’a “smart”, but there are probably reasons it hasn’t already changed everywhere else.
> 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.
Re: Tesla shares 48V architecture with other automakers
#375Earlier quoted context omitted.
What everyone was waiting for was for Italians to make the huge casting press so that castings could be done in mass production at automaker margins.
Despite Tesla's boastings, large casting machines have existed before. Automotive use is the new part.
Essentially it was question casting of this size being automated at car maker scale. Bigger castings were integrated before on assembly lines, but at higher costs and complexity before Italians made the large mostly automated caster that Tesla called GigaPress (iirc) - it's essentially COTS factory equipment.
Re: Tesla shares 48V architecture with other automakers
#376Earlier 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.
The mechanical backup for a drive-by-wire system is different to all those other things in that it's a critical safety issue. If _anything at all_ happens to the electronics while driving then it's important that you can stop the vehicle safely. That mandates manual brakes and steering, even if they're barely effective at all without power it's a lot better than nothing.
I hear it’s kind of a pain in the ass to do a front end alignment on the drive by wire systems.
Re: Tesla shares 48V architecture with other automakers
#377Many 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…
Good look doing DIY work on the 48V network of a modern car, ICE or EV or 12, 24 or 48 V doesn't matter.
And the past 12 V systems are dead easy to work on. On older cars that is, as soon as you have electronics and bus systems DIY basically requires deep car electronics knowledge and skills.
Re: Tesla shares 48V architecture with other automakers
#378Earlier quoted context omitted.
Given the choice almost any EE would probably pick the higher voltage system for cost saving reasons, but I imagine they were mostly constrained by legacy compatibility requirements here. It’a “smart”, but there are probably reasons it hasn’t already changed everywhere else.
> 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?
Re: Tesla shares 48V architecture with other automakers
#379Earlier quoted context omitted.
Dumb question but why does deciding to run at a higher voltage decrease the amount of wiring necessary? And why not increase it even further then?
48V is good because a lot of safety standards have the cut off for 'extra-low voltage' at 60V DC, gives you a bit of margin (when battery charging it pushes up to be in the 50s for example). Some battery systems I've seen at 56 volts nominal too. so sometimes people do have a bit higher-voltage ELV systems. 48V still lets you touch both conductors with dry hands and it's still very unlikely for you to be able to get…
If you can't feel 48 V with your hands I'd recommend moisturizer, because you have very dry skin.
Re: Tesla shares 48V architecture with other automakers
#380Earlier quoted context omitted.
Tesla didn’t invent 48 volts either. The EV and hybrid electric world were talking about 48 volts when Musk still worked at PayPal, if not earlier. One of the examples pulled out at that time was that you could shave a couple pounds of copper off the alternator by running it at 4x the voltage. Much thinner wires.
> 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.