New 48V vehicles don’t need a separate 12V battery to support lower-voltage systems

Electric power module supplier Vicor Corp. is pointing out that automakers can enjoy the benefits of 48V electric systems in their vehicles without immediately replacing the many familiar 12V devices employed in their cars.

Tesla’s new CyberTruck has entirely eliminated the traditional 12V low-voltage power network in favor of an all-48V configuration. While this is the likely end game for other automakers, those companies will want to take time as they migrate away from 12V devices that have proven reliability, reports Greg Green, director of automotive marketing for the company.

There are more than 100 12V devices in vehicles, whose replacements will each need testing, Green pointed out. “Replacing those with 48V devices requires a few thousand engineering hours and hundreds of thousands of dollars testing,” he said.

Vicor’s 48V zonal power modules provide automakers the ability to reduce the thickness of wiring in vehicles to 10-gauge while delivering high power to devices that need it. But they can also supply 12 volts to those legacy devices that carmakers want to retain while they test their eventual 48V replacements, Green said.

Some carmakers are addressing this situation by installing a 12V battery to run a separate 12V power network, but Vicor’s power modules can convert power from EVs’ high-voltage battery packs to provide that power without needing a separate battery. That saves 29 lbs. of weight in vehicles that are struggling with their mass because of the traction batteries.

“Our DC-DC conversion devices work so fast that we can create a virtual battery rather than having a 48V battery,” Green explained. “We’re able to convert power at 8 million amps per second, which is as fast or faster than most batteries transmitting power.”

Those who’ve been in the industry a while will recall that we were told a generation ago that cars would be switching to 48V, but that never happened. “In the early 2000s, we were told 48V was the next thing coming,” Green recalled.

But the inertia of 12V devices, with their low cost and proven reliability was too much for the 48V advocates to overcome, leaving the technology limited to isolated subsystems for engine stop/start systems, rear-wheel steering, and active suspension.

The shift to EVs means that power generation no longer depends on the familiar 12V alternator, making the shift more frictionless for automakers, Green noted. Now, there’s a high-voltage battery whose power needs to be converted to usable levels for the various devices on the vehicle. “When you have a high voltage battery that has to be stepped down, 48V is the natural first resting place,” he said.

That’s because it falls below the threshold of being injurious to people, should someone come in contact with the power, while providing good power level for those applications that need it.

For those applications that don’t, there isn’t much incentive for automakers to rush them to 48V, and Vicor’s ability to provide 12V in real time makes the idea of keeping some legacy systems at that level even more appealing.