Why haven't we moved to higher DC voltages?

[Dave Koehler]

The honest truth? The old people in the industry are resistant to change. OEMs never want to take the R&D and validation hit on changing tech, so they sit around and wait for someone else to do it.

48V is already here, and it will soon take over. Anyone who says otherwise clearly doesn't work in the OEM field.

If you work in the automotive OEM field please tell us more about your work.

[emsvitil]

The minimum size wire wouldn't be based on amps.

The high watt loads could use a smaller/lighter wire, but for low watt loads you need to worry more about wire robustness/surviveability in a vehicle environment. You can't have vibration destroying the wires or the wires and connectors coming apart if it has been removed a couple of times.

Plus the cheapest wire might not be the smallest wire.

[LoganD]

They re-engineer the parts every few years anyway. An ABS module from 2010 isn't the same as one from 2019, so it's not a big deal to change the voltage.

They don't re-engineer everything to that extreme of a degree, though. There's always going to be legacy hardware.

At any rate, this isn't the kind of engineering I'm talking about. I mean the type of things they would have to do to ensure that absolutely nothing from a low voltage system is used in a high voltage system. Especially as it would be prohibitively expensive to do a 100% roll-in, so there would be legacy systems in place that would have to run on their own separate buses.

I can't think of a single vehicle made that started life 100% fresh, with no shared components with other or previous models. That's the sort of thing that would have to happen with a voltage change. It was not terribly difficult in the 50s and such, when you had negligible electrical components and the "electronics" was your kid's ham radio riding in the back seat.

There's already cars with 48V systems in production. This is not theoretical.

You underestimate how thoroughly everything is re-engineered with every new vehicle platform. There is almost nothing that is carried over when a platform is changed.

[LoganD]

The honest truth? The old people in the industry are resistant to change. OEMs never want to take the R&D and validation hit on changing tech, so they sit around and wait for someone else to do it.

48V is already here, and it will soon take over. Anyone who says otherwise clearly doesn't work in the OEM field.

If you work in the automotive OEM field please tell us more about your work.

I design powertrains for future vehicles. I used to be called a combustion engineer, but it's impossible to avoid electrification so I'm involved in that too. The stuff I'm working on will be in production in 4-5 years, that's generally the timeline from concept/prototype to full production.

[WoundUp]

The C8 Corvette was supposed to be getting a 12v/48v system. Whatever happened with that? I read in a few places that it has been designed into the car for future use but nothing I've seen has actually confirmed that to be true, yet.

[JoePorting]

I often wonder about this issue too. I assume it all comes down to cost. The objective of the OEM's since day one is to make cars as cheap as possible. Since this would raise cost with no major benefit, it isn't considered.

[Dave Koehler]

There's already cars with 48V systems in production. This is not theoretical.

Interesting.
What vehicles are utilizing 48 volts?
Is it the whole vehicle or just specific systems?

[LoganD]

There's already cars with 48V systems in production. This is not theoretical.

Interesting.
What vehicles are utilizing 48 volts?
Is it the whole vehicle or just specific systems?

VW group have several. Right now it's hybrid 12V/48V simply because it's difficult to get 48V replacement batteries if your battery fails. That will improve.

[Schurkey]

There used to be all sorts of talk in the trade magazines about the 42 volt future. (This would be a nominally 36 volt battery and a 42 volt alternator, or 3 times our current 12/14v systems)...

...In short, there is no reason to change.

Yes. I remember reading the magazines that were bragging up the higher voltage systems as "the coming thing".

I believed it was a solution in search of a problem to solve; and with enormous associated teething problems in the systems that were supposed to supply or "need" the additional voltage.

I worked in a manufacturing facility for city buses. Guys there would occasionally claim they were "shocked" by the 24-volt (paired 12-volt batteries in series) systems we were using. Never happened to me, I don't know how a "24-volt" system could have enough voltage to shock someone...but I heard the complaints.

[Dave Koehler]

There's already cars with 48V systems in production. This is not theoretical.

Interesting.
What vehicles are utilizing 48 volts?
Is it the whole vehicle or just specific systems?

VW group have several. Right now it's hybrid 12V/48V simply because it's difficult to get 48V replacement batteries if your battery fails. That will improve.

What individual systems are currently benefiting from 48 volts?

[Truckedup]

i spent a carrer as an electrician and contractor..You can get a shock from 24 volts ,but it'll be mild...48 volts under the right conditions could give a noticable shock but I don't think it would be dangerous to a healthy person.For the most part, the National Electrical Code starts at 50 volts...

[LoganD]

Interesting.
What vehicles are utilizing 48 volts?
Is it the whole vehicle or just specific systems?

VW group have several. Right now it's hybrid 12V/48V simply because it's difficult to get 48V replacement batteries if your battery fails. That will improve.

What individual systems are currently benefiting from 48 volts?

Anything electromechanical benefits. This would include active roll bars, active suspension, ABS, ESP, electronic diffs, etc.

[WoundUp]

Continental, who is said to be working with Chevy on the Corvette 48V hybrid system, claims a 21% increase in fuel mileage in real world urban environments.

https://www.continental-automotive.com/ ... chnologies

[peejay]

They re-engineer the parts every few years anyway. An ABS module from 2010 isn't the same as one from 2019, so it's not a big deal to change the voltage.

They don't re-engineer everything to that extreme of a degree, though. There's always going to be legacy hardware.

At any rate, this isn't the kind of engineering I'm talking about. I mean the type of things they would have to do to ensure that absolutely nothing from a low voltage system is used in a high voltage system. Especially as it would be prohibitively expensive to do a 100% roll-in, so there would be legacy systems in place that would have to run on their own separate buses.

I can't think of a single vehicle made that started life 100% fresh, with no shared components with other or previous models. That's the sort of thing that would have to happen with a voltage change. It was not terribly difficult in the 50s and such, when you had negligible electrical components and the "electronics" was your kid's ham radio riding in the back seat.

There's already cars with 48V systems in production. This is not theoretical.

You underestimate how thoroughly everything is re-engineered with every new vehicle platform. There is almost nothing that is carried over when a platform is changed.

In the field, I'm not seeing that. There is a lot of carryover both between designs and carried forward into replacement designs. Design inertia is a thing because clean sheets are prohibitively expensive, and there is usually no positive value in new for the sake of new.


If anyone was going to do it, I'd wager it to be a smaller car company that contracts out everything electronic to a single supplier like Bosch or Hitachi. (Probably Bosch, Hitachi is a follower not a leader)

I do hope you don't think I am being combative! I ask questions because I want to understand rationale. Having to throw away a lot of legacy items like bulbs is a huge thing. And on the technician side, having to get 48v capable scantools would be a huge expense. As much as people hated OBD-II twenty-plus years ago, having a single standardized DLC is a huge cost saver.

[tjs44]

The marine industry with larger boats has used a lot of 24V for years.I have found having a boat with 24V that the average marine store like West Marine does not stock virtually any 24V stuff excep for light bulbs.I would suspect the same would be true with our auto parts stores until it really became main stream.Tom