A new power paradigm is emerging in automotive design, enabling higher efficiency, simpler architectures and raising a fundamental question: is the 12 V system still relevant?
The article is based on the talk at the EFY Expo Pune 2026 called ‘Rethinking Automotive Lighting for the 48V Era’ featuring a speech by Mahendra Patel, Electronic Design Consultant, AIGHTECH Services Pvt Ltd, India. It has been transcribed and curated by Saba Aafreen, Tech Journalist at EFY.
It is genuinely exciting to witness the pace at which India’s semiconductor and electronics ecosystem is evolving. Across recent exhibitions, one trend stands out clearly which is the shrinking of the turnaround time from prototype to production. This is more than just faster execution, but reflects a maturing ecosystem that is learning from neighboring markets, particularly China, whose remarkable speed of evolution offers lessons that can be thoughtfully adapted to the Indian context.
Rethinking the 12 V Legacy
As the ecosystem evolves rapidly, it is equally important for our hardware to advance to keep up with the latest trends. The automotive sector is a good example. Vehicles once ran on 6 V systems, then moved to 12 V lead acid batteries as electrical loads increased, which became the standard. Today, there is a clear shift toward 48 V systems. Modern two-wheelers and three-wheelers are already moving to 48 V and even mild hybrid cars are adopting 48 V batteries.
But are we really transitioning everything to 48 V? The answer is no. Most systems still carry both 12 V and 48 V. That is where I start to question this approach. With the semiconductor solutions available today, do we really need both battery systems in the same vehicle? To me, this also means we need to challenge the long-held assumption that 12 V must always be retained. That is no longer necessarily true.
If I look at the system level, the challenges are quite clear:
- Reducing cost, weight and overall system size
- Simplifying connectors and wiring harnesses
- Improving efficiency and reliability
- Ensuring designs are truly future-ready
In a typical 12 V system, as more features are added, battery load keeps increasing, driving higher circuit complexity. Higher current demand increases cost, weight and size, which is a primary limitation of the existing architecture. Connector design further compounds this. Currents in the range of 3 to 5 amps require larger pins and copper-heavy wiring harnesses, adding both weight and cost. Efficiency suffers, heating increases and reliability becomes a concern. Wherever there is scope to improve reliability, it should be actively considered.
This brings me to a broader question: are our designs really future-ready? As battery systems evolve, the rest of the vehicle architecture should evolve with them. In modern electric vehicles, especially two-wheelers and three-wheelers, the traction or motor controller is already predominantly powered by 48 V. This is true for most scooters and three-wheelers on Indian roads today. Even in cars, systems like H Box or ISG are moving to 48 V. Yet despite this shift, the 12 V battery continues to remain in the system.
Lighting Losses: The 12 V Bottleneck
Instead of reviewing all 12 V subsystems, let me take lighting as an example. It is no longer just basic on and off. Modern lighting is becoming increasingly sophisticated, with blinking, animation and dynamic behaviour that bring vehicles to life. In a typical two-wheeler, the front lighting system alone draws nearly 40 W across high beam, low beam, DRL and indicators. These loads are usually driven by ~14 V LED drivers using a non-synchronous buck-boost topology involving a diode and a MOSFET and this is where efficiency begins to drop, often approaching 50%.
In conventional architectures, power comes either directly from a 12 V battery or via a 48 V to 12 V converter. The initial 48 V to 12 V conversion itself introduces roughly 10% loss. A DC-DC converter then reduces 48 V to about 14 V for the LED driver, while the buck-boost topology compensates for variations in LED forward voltage. When these stages are combined, overall efficiency drops to nearly 77%. In practical terms, almost one-fourth of total power is lost purely in conversion. Looking deeper, about 25% of the loss comes from circuit conversion, with wiring harness and protection elements such as input diodes pushing total losses close to 30%. Nearly one-third of battery energy is not used effectively.
A native 48 V architecture offers a more efficient path. Instead of stepping down to 14 V, a constant voltage synchronous buck converter can generate an intermediate voltage of 36 to 40 V. This matches typical LED string requirements, where high beam and low beam voltages are around 15 V each and remain below 30 V even in series, enabling more efficient direct driving. Replacing diodes with MOSFETs reduces conduction losses and techniques such as zero voltage switching minimise switching losses, allowing the first stage to reach around 92% efficiency.
This intermediate stage can then feed multiple constant current synchronous buck stages for LED driving, each also operating above 92% efficiency. Combined, overall system efficiency rises to roughly 84.5%, a gain of about 7.5% over conventional approaches. Further reductions in harness, connector and protection losses can add another 5%. Altogether, moving from a 12 V architecture to a 48 V system can deliver a net efficiency gain of 12 to 13%, making a strong case for rethinking power delivery in modern vehicles.
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