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The Kia EV9 emerges as a powerful contender in the all-electric SUV market, boasting not only competitive performance but a remarkably innovative 800V electrical architecture. At Munro & Associates, where expert teardown analysis meets lean engineering principles, we love spotlighting design breakthroughs that solve tough problems affordably. Kia’s solution to high-speed EV charging with their 800V system is one such standout.
The Importance of 800V Systems in Modern EVs
Most electric vehicles on the road today use a 400V architecture. While sufficient for daily use, it imposes significant limitations on charging speeds, especially during road trips where time spent at charging stations matters. Vehicles running on an 800V system, such as the Porsche Taycan or Lucid Air, charge significantly faster. However, these high-end EVs come with premium price tags, keeping 800V benefits out of reach for the average consumer.
Enter the Kia EV9, the most affordable 800V EV SUV currently on the market. Designed with a spacious cabin, dual motors (379 total horsepower), and a 99.8 kWh battery, the EV9 offers up to 270 miles of range—with more on rear-wheel-drive versions. But its standout feature is how Kia engineers achieved fast, efficient charging without adding costly, bulky components that plague other 800V attempts.
Why 800V Architecture Is Hard—and Expensive
To achieve 800V architecture in a vehicle, OEMs must overcome a series of electrical and thermal management challenges. One of the biggest hurdles is integrating a boost converter that can elevate the standard 400V input (from DC fast chargers) to 800V—required to efficiently charge an 800V battery pack.
This isn’t a simple feat. A boost converter capable of handling up to 350 kW of power must also ensure ultra-smooth current delivery to the battery. Any current ripple can damage cells or reduce charge efficiency. That’s why most designs use large, heavy filters—often weighing around 25 pounds and filled with costly copper and steel—to stabilize the current. These filters are expensive, space-consuming, and contrary to lean automotive design principles.
Most automakers, faced with this high-cost hurdle, simply delay adopting 800V systems. Hyundai and Kia, however, found a way around it.
The Motor-as-Filter Breakthrough
During the teardown of the Hyundai Ioniq 5, Kia’s cousin platform to the EV9, Munro engineers discovered something unusual: a fourth wire connected to the motor. Traditional three-phase motors only need three electrical connections for the three windings. So, why the fourth?
Digging deeper and reviewing patent documentation revealed the answer: Kia and Hyundai use the motor windings themselves as part of the boost converter’s filter. In other words, instead of installing a separate filter, they route charging current through the motor windings, smoothing out the ripple and delivering clean, steady current to the battery.
This fourth connection enables the system to reroute current internally, transforming an otherwise passive motor during charging into an active component of the power electronics system. The result is a leaner, lighter, and less expensive charging solution.
Engineering Elegance and Real-World Benefit
This is a textbook example of elegant engineering: reusing an existing component (the motor) to perform a secondary function (filtering). By avoiding the need for a separate shoebox-sized filter, Kia saves hundreds of dollars per unit while also eliminating 25 pounds of dead weight—benefits that directly improve vehicle performance, cost-efficiency, and sustainability.
In practical terms, this allows the EV9 to recharge from 20% to 80% in approximately 20 to 25 minutes using a 350 kW DC fast charger. Even on less powerful chargers, it outpaces many competitors in the same segment. Those minutes saved make a real difference during long-distance travel.
From a lean design perspective, this reuse of the motor as a functional filter is the kind of problem-solving that Munro & Associates celebrates. It embodies core principles of design simplicity, cost-effectiveness, and systems integration.
Comparison: Kia vs Rivian, Tesla, and Mercedes
Kia positions the EV9 in the same class as electric SUVs like the Rivian R1S, Mercedes EQS SUV, and to a lesser extent, the Tesla Model X. But while Rivian and Mercedes offer luxurious interiors and solid performance, their pricing tiers are far above what the average family can afford.
Tesla’s Model X delivers faster acceleration and more brand recognition, but its 400V architecture limits charging performance compared to Kia’s 800V system. Even Tesla’s proprietary Superchargers don’t fully exploit what an 800V system can offer.
Kia instead focuses on real-world advantages: competitive acceleration (0–60 mph in about 4.5 seconds for the GT model), excellent range, and road-trip readiness thanks to shorter charging stops. The result is a vehicle perfectly suited for practical family use—without sacrificing engineering sophistication.
Lessons in Smart Automotive Design
The EV9’s approach highlights a growing trend in automotive engineering: doing more with less. Rather than brute-forcing problems with expensive add-ons, the best engineers ask, “What can we reuse or repurpose?”
This strategy also aligns with the growing pressure to reduce vehicle weight, cost, and environmental impact—all while increasing functionality. By embedding new utility into existing components like the motor windings, Kia meets the moment with ingenuity and precision.
At Munro & Associates, we’ve long emphasized the value of such lean thinking. It leads to more durable, efficient, and profitable vehicles—and ultimately, happier customers.
A Call to Engineers and Investors Alike
Whether you’re an engineer looking to draw inspiration or an investor scouting the next wave of smart EV platforms, the Kia EV9 offers more than a smooth ride. It represents a shift toward sustainable innovation that doesn’t cut corners but redefines them.
As battery technologies evolve, such clever reuse of core components may become standard across the industry. But for now, Kia and Hyundai have a clear lead in integrating cost-effective, high-performance 800V solutions. Their foresight, and willingness to challenge conventional design assumptions, deserve recognition.
Final Thoughts: The 800V Edge
In a market flooded with copycat EV designs, Kia stands apart. Their clever integration of motor windings as a filtering system for high-speed charging is not just a cost-saving hack—it’s a vision of where automotive engineering is headed.
The Kia EV9’s 800V architecture proves that innovation isn’t always about adding more—it’s about doing better with what you already have.
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