BONUS: The Tech Sheet (Pt2) - Why Do Cutting Edge EVs Still Have A 12 Volt Battery?
EV News Daily - Technology and Business of EVs
BONUS: The Tech Sheet (Pt2) - Why Do Cutting Edge EVs Still Have A 12 Volt Battery?
EV News Daily - Technology and Business of EVs · Sep 24, 2025
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Welcome back to EV news daily. Welcome to the tech sheet, the name I give to special bonus episodes
that looks at the tech behind the world of electric vehicles. And today is part two,
wider cutting edge EV still have a 12 volt battery. Well, yesterday on the podcast,
we told you about the era of six volt dominance, how it moved to 12 volts, the failed attempts to
go to 42 volts in the 1990s, bridging the gap between your traction battery and the low voltage
battery, critical functions of why you even have a 12 volt system inside your EV power
management, charging systems, components and supply chains, plus the considerations of going to 48
volts and why Tesla is trying to persuade the industry to do exactly that. If you missed any
of those topics there on yesterday's part one of this little series, I guess a two part series,
I admit, as we look today at part two of why your cutting edge EV has the old fashioned 12 volt
battery. A reminder, our bonus shows are exclusively for Patreon supporters for the first seven days,
only Patreon insiders get early access, their name on the list of legends for executive producers
and above, and the power to shape future shows. If being in the know and supporting my work sounds
like something you'd like to do, no pressure, zero pressure, but if you want to feel free to
have a look at patreon.com, p-a-t-r-e-o-n.com slash EV news daily to be part of something really
special, the incredible people that get this show on the air every single day. Now this is part two
of our look at the 48 volts move that Tesla is trying to do. I left you yesterday by telling you
about the Cybertruck 48 volt architecture and having to redesign themselves as part of a very
vertically integrated company. Because you can't just, if you're launching the Cybertruck on a 48
volt system, open up the parts catalogue. It's online obviously these days, but I like the image
of sitting down with, you know, a catalogue and flicking through. What do we need? One of those,
two of those, you know, 200 of those, the wiring, the switches, the components. There are 48 volt
things out there, but just not in the way that Tesla needed. So much like the automotive industry of
the 1950s, when we moved from six volts to 12 volts, they had to do a lot themselves. Tesla's 48
volt architecture demonstrates high voltage systems potential when properly implemented.
If you quadruple the voltage, you can deliver the same power at a quarter of the current.
And that creates, it's literally cascading benefits throughout the entire vehicle.
This is why Tesla's a really big fan of moving to a higher voltage, low voltage system, if that
makes sense. Wire harness weight, that's a really big deal. That's probably the most tangible benefit
that most people would understand in the world of EVs because weight is efficiency, isn't it?
Sandy Munro, quite famous for providing tear down services in different sectors,
he looked at the Cybertruck and revealed a 73% wiring weight reduction versus 12 volt systems,
with 78% overall weight savings when combined with the Ethernet based communication system.
These reductions are particularly valuable in EVs, every pound translates into performance
and range. Efficiency improvements extend beyond weight savings to reduced resistive losses in
electrical distribution. Power losses are proportional to current squared, so reducing
current by four results in approximately 16 fold power loss reductions. Now for EVs,
efficiency directly impacts range. Tesla are amazing at eking out every last amp power,
watt hour. These translate to meaningful performance and improvements, which ultimately
means a more satisfied consumer. Tesla's 48 volt system enables new technologies
impractical with 12 volt systems. The Cybertruck has steer by wire, that in itself, not just electrical
power steering, but a steer by wire system would stress a 12 volt system. This eliminates the
mechanical connection between what you hold in your hands and what the wheels are doing on the road.
That requires substantial electrical power if it's going to be reliable. This system demands
approximately three times the electrical power of maybe what an American house was pulling in
the early 1970s. This is how much power we need. 48 volts was essential for that technology.
Despite significant advantages, Tesla's 48 volt system required addressing numerous tech
challenges. Illustrating voltage system transition is really complex. Primary challenges involve
maintaining compatibility with the existing 12 volt stuff that's out there where the conversion
didn't justify development. I left you on part one yesterday talking about it wasn't an all or
nothing with the Tesla Cybertruck. It was a hybrid approach. Less frequently used components,
seat motors. I mean, how often do you change your seat? Maybe if you share a vehicle with
your partner, every time each of you gets in, the seat might move. If it reads your key or your phone
or the door lock actuators, things like that. They're not used every second of the journey,
so they can remain on 12 volts due to supplier cost dynamics and efficiencies.
The required power management systems between voltage levels had to be worked out for reliability
and safety. Developing 48 volt components meant Tesla had to work closely with its suppliers
or even do its own thing. Like I said, power window motors required custom 48 volt designs
needing collaboration with its suppliers like a bros, I think it was. While still using traditional
DC designs, higher voltage operation allows reduced wire gauge more efficiency. Safety
considerations for a 48 volt system needs attention as higher voltages, well below the
dangerous thresholds, it doesn't require all the orange high voltage cable shielding that you see
if you look underneath the bonnet of your EV. Do require different handling procedures, safety
and training. Tesla addressed concerns through different connector designs, including industry
standard light blue coloring for the 48 volt connectors, enhanced secondary locking systems
and robust sealing, preventing any moisture ingress. So what are the benefits and what are
the challenges of doing what Tesla did with the Cybertruck? Why don't all car makers go,
oh that's better, we'll do it that way. Well, technical and economic benefits of 48 volt extend
across all the different bits of vehicle design and operation, creating a really compelling argument
for an industry wide adoption. Most immediately apparent is the electrical efficiency and
material usage, but implications reach deeper than that. Material efficiency represents the most
well in the most quantifiable 48 volt system benefit. Current reduction requirements enable
a lot smaller wire gauges throughout the vehicle, substantial copper saving, Cybertruck copper content
was reduced by approximately 100 pounds by going 48 volts. That at 320, say 320 dollars per vehicle
is not a massive cost saving, but at the scale Tesla works at or at least they wanted to sell
that many Cybertrucks is a significant saving. Multiplied across annual production volumes
of everything that maybe Tesla made, if they all went 48 volts, are material savings in terms of
hundreds of millions of dollars, if not more. Weight reduction benefits extend beyond the
raw material savings to include secondary effects on vehicle performance and efficiency.
In EVs where weight is everything, Tesla's 73% wiring harness reduction represents a meaningful
improvement. These weight savings also reduce structural requirements. Think about vehicle
suspension and chassis components, creating additional cost and weight optimization as well.
Manufacturing efficiency improvements represent another significant system advantage of going 48
volts. Traditional 12 volt wiring harnesses require extensive manual labor for things like assembly,
routing the cables and and even just connecting them all up as well as thick wire gauges are
difficult to manipulate and and route through a really complex vehicle structure. A thinner wire
with 48 volt allows increased automation in harness manufacturing and installation reducing
labor, improving consistency. And beyond the efficiency improvements, 48 volt systems would
enable entirely new technology in practical or impossible with 12 volts. High power accessories
previously needing either mechanical operation, maybe hydraulic operation could go electrical,
providing improved precision, reduced maintenance requirements, better vehicle system integration,
active suspension systems are a really good example that I can think of initially as 48 volts
power benefits. Bentley, Audi, Porsche, they've all done 48 volt powered active suspension systems.
What they do is they counteract body roll in the turns so you get better ride quality,
they adapt to road conditions, but these systems are really power hungry. They require substantial
electrical power for rapid actuator response and they had to use 48 volts for that. Electric
would provide efficiencies, traditional turbochargers use exhaust gases in engines,
creating acceleration like you could in the old world of combustion use more 48 volt systems to
provide boost pressure immediately, eliminating turbo lag, making engines at the end of their
life cycle, the next 20 years or so as we say goodbye to combustion. Mercedes-Benz have done
something in several models using 48 volt power to drive things like compressors for boost response.
Advanced driver assistance systems, ADAS, autonomous driving increasingly require
a lot of sensors in China, a load of LiDAR, nearly all cars a ton of compute and even actuator power.
Power requirements exceed what 12 volts can do, making 48 volts just sufficient really for
the next level of ADAS whilst maintaining safety voltage thresholds.
So there are loads of clear advantages to doing what Tesla asked the industry to do two years ago.
Please think about implementing 48 volt, but there's a reason they haven't,
technical, economic, logistical challenges. If you've missed part one, then I'll quickly recap.
This is the existing automotive supply chain, billions of dollars, hundreds, probably billions
of dollars over the years cumulatively have been spent on the supply chain of building facilities
and knowledge that make 12 volt stuff. Component availability represents immediate practical
barriers. So if you make an EV, if you're an OEM and you make an EV, should we go 48 volts?
Okay, can we get all the bits we want from our existing suppliers? Do we need new supply chains?
There are development costs, minimum order qualities, things like that. Scale will bring it down.
Electromagnetic compatibility, EMC considerations, no one ever talks about that.
They become more complex with 48 volt systems, higher voltages and faster switching frequencies
can generate increased EMC interference. And so while challenges, they're all solvable,
all fixable problems, but require engineering and testing to ensure automotive EMC compliance.
I mean, even AM radio, there's this campaign of let's not hurt AM radio with electric vehicles,
kind of crazy. By the way, I have a like 25 year career in broadcast radio before I started
this podcast as my only career now. So I used to work an AM radio station, like I'm not anti AM
radio, but come on, in a digital IP connected world, should we not move forward with clean
green transport because there's an AM radio lobby cost considerations are also really important.
48 volt systems can reduce material costs. I've established that reduced copper usage,
but initial development component pricing premium manufacturing process changes
that all ramps up the cost before it comes down. 48 volt is the long game safety and service
considerations are some of the biggest long game in the automotive industry. If you make a vehicle
today, that's great. Now it has to be service for 10, 15, 20 years and the rest. So shock hazards
need to be minimized. It's 48 volts. So it's fine. It's safe, but different service and training
procedures and safety protocols for a vehicle that is then in service for decades, service
technicians, diagnostic equipment, all of that needs updating. Automotive industry 48 volt technology
is out there. I'm not pretending that Tesla's the only one doing it tends to be led primarily by
the European premium manufacturers putting in mild hybrid applications rather than
the whole vehicle level architecture. This reflects maybe a conservative strategy
to do things piecemeal Audi pioneered 48 volt systems back in 2016. The sq seven came out and
that had a really sophisticated mild hybrid system that I think was only 48 volt power
for the electric supercharger, the active suspension, the sq seven had a lithium ion 48
volt battery, a belt driven alternator starter and another 12 kilowatts of additional acceleration
power. Mercedes Benz adopted 48 volt mild hybrid systems across their model line,
clse class s class, the the three liter engines they had all included 48 volts power to replace
things like mechanical belt drives and accessories like air conditioning compressors and coolant
pumps. This allows the systems to continue operating when engines shut off during stop
start operation then the cabin comfort is not affected. BMW was pretty aggressive actually
with 48 volt back in the day with over 50 models incorporating their 48 volt starter generators.
BMW systems provide another 10 horsepower eight kilowatts during starting and acceleration
moments while supporting the engine workload. The company strategy focuses on 48 volt systems
in its combustion range to make them better. But if you look at the Asian automakers,
they did it with a bit more caution actually focusing on specific applications where benefits
outweighed the cost of implementing. So if I think about Hyundai and Kia, they went 48 volt in
their mild hybrids like Tucson, Santa Fe, Seats, Sportage with diesel engines where efficiency
benefits are probably the most pronounced. Toyota of course 48 volt mild hybrids, Land Cruiser,
Hilux, a departure from their hybrid powertrain focus, but again using turbo diesels 48 volts
systems with some DC DC conversion designed for simple existing powertrain integration
while maintaining the compatibility to operate what they say in extreme conditions like water
wading and stuff like that. Hyundai announced ambitious plans to go to 48 volt architecture by
the end of the decade. That is probably the most comprehensive voltage system transition
from the major OEMs. The strategy involves working with suppliers to start building a 48 volt
component ecosystem whilst maintaining profitability. Hyundai's approach to applications beyond
automotive extending 48 volt technology to things like their robotics like Boston Dynamics,
that's all under them as well now for component development is going to help with things like
economies of scale. Let's talk about the market and how it could adopt how the cars that we drive
not tomorrow but in time could all be using the next generation of low voltage technology.
We'll take a quick break. I'll have a slurp of coffee. We'll finish off and round out
the end of part two of this two part series on why your cutting edge EV still has 70 year old
12 volt technology. Stick around back in a moment.
Okay, welcome back to the podcast. Let's finish off part four if you like as it's a two part series
on our low voltage systems in our EVs. The automotive 48 volt system market had a big
growth recently. Projections also show expansion from 6.47 billion to 36 billion over the next six
or seven years a 24 25% compound annual growth rate. So various movement in the low voltage
system in automotive growth is driven by emissions regulations fuel efficiency requirements and
modern vehicle power demands. European markets have been leading 48 volt adoption because of
more stringent CO2 emissions regulations with mild hybrid systems economically attractive now
to meet those regulations. The European Commission's plan to reduce automotive emissions by almost 40%
by the end of the decade is an incentive to make that jump to 48 volt. Market research indicates
48 volt systems will appear in maybe a fifth of all vehicles sold globally this year again not the
entire vehicle architecture but some parts of it. Well Tesla's decision to share their 48 volt
implementation with the world was a really big moment. I think a lot of people interpreted this
as a little bit of maybe Elon Musk bravado saying we know how to do it better than everyone so
let me remind you when they launched the cyber truck they also wrote they wrote the book on 48
volt they effectively wrote a guide called how to design a 48 volt vehicle and he said oh I've
sent it to all the other automotive CEOs so they can have a good read of it. I think people again
dismissed it as Mr Musk being well you know the showman and all those kind of things but
that's a remarkable strategic thing to do to raise that I think with the wider public the
attention that Tesla and the CEO can captivate people sometimes I don't think they kind of
realized how important that was and then after the launch it seemingly all went away. So the
initiative confirmed at the time by people like the Ford CEO Jim Farley acknowledged as well by
Elon Musk afterwards demonstrates how Tesla have confidence in their tech but want to transform
the industry and no doubt Tesla's got skin in the game document it's never been shared as far as I
know I did a lot of research for this podcast series I couldn't find that document online but
documentation sharing has happened some of the detailed technical specifications have appeared
online you can't guarantee that that is true sections of it have appeared online you can't
guarantee the authenticity of that Ford CEO Jim Farley's confirmation that Tesla sent the
how to design a 48 volt vehicle documents to him validate the reports that do seem to make this
credible Farley's response that Ford's next-gen team has been on a similar path suggests that look
all out to automakers are looking at this Tesla's motivation for sharing the documentation with other
CEOs extends beyond just being you know altruistic the primary drivers appear to be Tesla's recognition
that if they want to do what they want to do with their vehicles so the steer by wire that the high
voltage stuff they need a component production ecosystem you know economies of scale that reduce
Tesla's costs they can't do it alone by encouraging competitors to also go 48 volt
it establishes the market it drives supplier investment it brings the cost down automotive
industry responses to the 48 volt documentation sharing has been positive in public statements
revealing the underlying skepticism perhaps about how practical the idea is Jim Farley
Ford CEO's that it was great for the industry and proposed some more collaboration to help the
supply base move to 48 volts however industry analysts analysis suggests the positive public
statements out there kind of mask these more significant concerns about how practical it is
we can kind of cope with 12 volts we've worked out ways to make 12 volt work in an EV world
legacy automakers have a different challenge and constraints to Tesla so existing model lines many
more models established supplier relationships some of them have more complex manufacturing
all designed around 12 volt supplier ecosystem responses were a lot more cautious by the way
reflecting the reality that if you're a component manufacturer you can't just
up sticks and go 48 volt overnight without significant investments and all of them are
working on razor thin margins two years after Tesla's cyber truck launch and the document
sharing initiative the automotive industry has not adopted a 48 volt EV plan it's not even been
discussed publicly it reveals a fundamental structural barrier that extends far beyond
just the technical considerations 12 volt systems persistence across the entire industry really
demonstrates how complex it is for the economies the technical side the organizational factor
in building an electric vehicle automotive supply chains represent the most significant
industry you know out there in terms of the the entire industry in terms of going 48 volt it's
the supply chain that would need to change the OEMs can say yeah this is a great idea we'll design
our vehicles differently unlike Tesla which maintains significant vertical integration and you
close working relationships with their suppliers and component manufacturing some of the traditional
automakers rely more heavily on either established supplier networks that have invested billions
like I say in 12 volt or they simply cannot work so closely with them to do it together scale of
supply chain challenges becomes apparent considering thousands of different components required for
modern EV production from a simple switch to a complex module it all has to be redone financial
analysis of the 48 volt system reveals complex trade-offs of making short-term transitions 48
volt offers long-term advantages efficiencies costs and things like that and vehicle performance
like the EVs would be better in time but development costs extend far beyond just the components
you know deep vehicle level integration testing validation even safety certification competitive
dynamic surrounding 48 volts adoption reveal how established industry leaders may publicly say
yeah we're looking at this it all makes sense let's collaborate even the technology offers clear
advantages but when it hits the bottom line are they going to transform their business even take
a hit in the short term when so many of them are looking at quarterly share prices and profit
targets and things like that the automotive industry's measured response to Tesla's plan
to go 48 volts highlights the potential evolution in the automotive industry hybrid architecture
is one thing and that's where they have gone 48 volts but to follow Tesla and entirely change
the way that you design a vehicle well that hasn't been forthcoming ultimately the way the car
industry works with 12 volt batteries even in a cutting-edge EV reveals this complex
interplay between we want to innovate and do amazing things but also there are established
systems that we have to stick to and for now while the future likely holds maybe a 48 volts
broader adoption transition is going to be measured in decades rather than years reflecting a
profound challenge as we go to EV and that's your podcast for today check out if you haven't
heard the first part I'm sure that's gonna make sense if you listen to that first in your feed
compared to what I've just talked about but either way round I hope you've enjoyed it thank you so
much for listening and I'll see you on the next one
About this episode
Exploring the necessity of 12-volt batteries in modern electric vehicles, this episode delves into Tesla's push for a 48-volt architecture, particularly in the Cybertruck. It discusses the historical context of battery systems, the advantages of higher voltage—like reduced weight and improved efficiency—and the challenges of transitioning from 12 volts. Notable insights include Tesla's collaboration with suppliers and the broader implications for the automotive industry, highlighting the complexities of supply chains and the cautious approach of legacy automakers in adopting new technologies.
Original notes
Welcome back to EV News Daily, welcome The Tech Sheet, the name we give to special bonus episodes which explain the tech behind EVs. Yesterday, in Part 1, we talked about:
➤ Electric Starter Innovation (1912)
➤ 6-Volt Era (1920s–1950s)
➤ Primitive Battery Tech
➤ Transition to 12 Volts (1953–1956)
➤ Efficiency of Higher Voltage
➤ Industry Standardization
➤ Failed 42-Volt Push (1990s–2000s)
➤ Dual Systems in EVs
➤ Critical Role of 12 Volts in EVs
➤ Manufacturing & Service Dependence
➤ Economic & Regulatory Inertia
➤ Tesla’s 48-Volt Revolution (2023, Cybertruck)
A reminder our bonus shows are exclusively for our Patreon supporters. For the first 7 days, only Patreon insiders get early access, their name on the list of legends for Executive Producers and above, and the power to shape future shows. If being in the know and recognised as a supporter sounds like you, join us now at patreon.com/evnewsdaily and become part of something special.
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