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Tesla shares 48V architecture with other automakers

electrek.co

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Re: Tesla shares 48V architecture with other automakers

#21

Post by londons_explore »

intrepidhero wrote: post #5

Why would a car need a 48V system for accessories? In general the things a car's 12V system powers have gotten less power hungry over time (LED's, heat pump) and in particular, an EV loses the highest power electrical device on the 12V bus, the starter. The typical equipment used for the entertainment and control systems are going to be much more available with 12V supplies, just because that's the industry standard.…

Most MOSFETS are 50 volt rated. 50 volts is a sweet spot for switching the most powerful load with the smallest and cheapest switch.

Re: Tesla shares 48V architecture with other automakers

#22

Post by intrepidhero »

jabart wrote: post #15
intrepidhero wrote: post #5

Why would a car need a 48V system for accessories? In general the things a car's 12V system powers have gotten less power hungry over time (LED's, heat pump) and in particular, an EV loses the highest power electrical device on the 12V bus, the starter. The typical equipment used for the entertainment and control systems are going to be much more available with 12V supplies, just because that's the industry standard.…

Power steering pumps are electric and have one of the largest wires in my truck. With an EV you also have a heat pump, maybe a heater, coolant pumps now that you don't a constant spinning pulley, windows, lights, headlamps, power doors, seats, radio, amplifier, small PC, etc. From the article "Switching to 48V architecture alleviates a huge number of challenges automakers are facing with 12V. The biggest one, though,…

I hadn't connected the dots that all the various pumps (and fans) have to switch from mechanically connected to the engine via the accessory belt to electrically driven. That's a fair point.

Re: Tesla shares 48V architecture with other automakers

#23

Post by mauvehaus »

intrepidhero wrote: post #5

Why would a car need a 48V system for accessories? In general the things a car's 12V system powers have gotten less power hungry over time (LED's, heat pump) and in particular, an EV loses the highest power electrical device on the 12V bus, the starter. The typical equipment used for the entertainment and control systems are going to be much more available with 12V supplies, just because that's the industry standard.…

Not that anyone is going to stick a plow on a Cybertruck, but holy shit is the hydraulic pump on one of those a huge current draw. It's 4AWG wire on mine. The battery is kind of marginal[0] and when I raise the plow, the volt meter goes down to 7-8 volts if the engine's at idle and the alternator can't supply the needed current. Gunning the engine improves the situation somewhat, but wow, was that an eye opener.

[0] Everything on that truck is kind of marginal, actually. If you aren't plowing for money, plow truck is the last stop before the big parking lot in the sky.

Re: Tesla shares 48V architecture with other automakers

#24

Post by bryanlarsen »

intrepidhero wrote: post #5

Why would a car need a 48V system for accessories? In general the things a car's 12V system powers have gotten less power hungry over time (LED's, heat pump) and in particular, an EV loses the highest power electrical device on the 12V bus, the starter. The typical equipment used for the entertainment and control systems are going to be much more available with 12V supplies, just because that's the industry standard.…

In the case of the cybertruck, the windshield wiper motor to drive that massive 4 foot wiper blade is 5hp and would require 300 amps at 12V. That's larger than a starter motor.

Re: Tesla shares 48V architecture with other automakers

#25

Post by intrepidhero »

pgeorgi wrote: post #9
intrepidhero wrote: post #5

Why would a car need a 48V system for accessories? In general the things a car's 12V system powers have gotten less power hungry over time (LED's, heat pump) and in particular, an EV loses the highest power electrical device on the 12V bus, the starter. The typical equipment used for the entertainment and control systems are going to be much more available with 12V supplies, just because that's the industry standard.…

https://de.wikipedia.org/wiki/Bordnetz#48-Volt-Bordnetz_im_A... explains (a bit) why German car makers are using 48V since ~2016 (in addition to the still existing 12V system, which seems to be the difference with Tesla, which went 48V-only). DeepL translation: The 12 V electrical system can barely cover the power consumption that modern vehicles need for their comfort systems. The "static" consumers completely overl…

A split 48/12 system makes a lot more sense. Run the heater/heat pump, power steering, coolant pump, etc on 48V and keep entertainment and controls on 12V.

Re: Tesla shares 48V architecture with other automakers

#26

Post by rational_indian »

Could have gone higher. Worth it in copper savings alone. IIRC the cars use AC motors. It needs to go through inverters anyway so there is some flexibility in how high you can go.

Edit: of course the motors are "AC" who would want a brush and commutator based motor in their car?

Re: Tesla shares 48V architecture with other automakers

#27

Post by firebat45 »

mccoyc wrote: post #3
sitkack wrote: post #2

TIL that 42V fizzled out https://en.wikipedia.org/wiki/42-volt_electrical_system I welcome the move to 48V, as one gets lots of cross over synergies from the 48V telco standard. https://www.servertech.com/blog/48vdc-power-and-the-backbone... https://www.st.com/content/dam/AME/2019/developers-conferenc... https://www.maximintegrated.com/content/dam/files/products/p... https://www.infineon.com/cms/en/applications/infor…

Agreed. 48V (actually -48V) has been used across telco central offices for decades.

How exactly do you define a negative voltage unless you are using some other voltage as a reference?

Re: Tesla shares 48V architecture with other automakers

#28

Post by firebat45 »

rnk wrote: post #18
r3d0c wrote: post #6

Earlier quoted context omitted.

weird comment... maybe we shouldn't feel the need to idolize humans...

We humans are all terrible on some level (except my mom, she was a saint), but if you have enormous power, you can help or hurt a lot of people based on your actions. Musk has a lot of power. He must be a terribly lonely person, not knowing if he can trust anyone or they just want something from him.

Nobody knows if they can trust anyone, not just rich people.

Re: Tesla shares 48V architecture with other automakers

#30

Post by londons_explore »

sitkack wrote: post #2

TIL that 42V fizzled out https://en.wikipedia.org/wiki/42-volt_electrical_system I welcome the move to 48V, as one gets lots of cross over synergies from the 48V telco standard. https://www.servertech.com/blog/48vdc-power-and-the-backbone... https://www.st.com/content/dam/AME/2019/developers-conferenc... https://www.maximintegrated.com/content/dam/files/products/p... https://www.infineon.com/cms/en/applications/infor…

I don't think they'll be able to use much of that with their 48v PoE ethernet standard...
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