Yasa Motors, the UK-based firm owned by Mercedes-Benz, has developed what it claims is the highest density motor ever made, delivering a massive 738 hp (550 kW) from a unit weighing just 13.1 kg.
That works out to 56 hp per kg, more than double the industry benchmark of 20 hp per kg, and sets what Yasa calls an unofficial world record for motor power density across any sector, not just automotive.
Right now, the electric motor with the highest power-to-weight ratio is the Equipmake HPM-400, producing 54 hp per kg. That Australian-built unit weighs 40 kg and is used in aerospace, space, and marine applications.
Yasa achieved its numbers during prototype testing last week. The impressive part, according to Yasa, is that the motor doesn’t rely on exotic materials like cobalt-iron laminations or Litz wire, nor does it use 3D printing.
Tim Woolmer, Yasa CTO and founder, told Autocar, “This result is a glimpse of what’s possible when deep tech, R&D and practical engineering comes together. We’ve shown that you don’t need exotic materials or experimental manufacturing processes to achieve record-breaking performance.
“What we’ve achieved here is not just a number – it’s a demonstration of scalable, production-ready innovation that raises the bar for electric motor design. And the most exciting part? We’re just getting started.”
Once the design is finalised, Yasa says it could produce up to 50,000 units per year at its Oxfordshire facility.
In a statement, Yasa noted that while the record is unofficial, it marks a significant milestone for the company and for what’s possible in practical, high-performance electric motor development.