Porsche advertises that a five-minute charge at the fastest 350- kilowatt public chargers can add about 60 miles of range with a charging peak of 270 kW. Hyundai makes a similar claim with more than 60 miles of added range in the same five minutes at a peak of 235 kW.
That’s because those 800-volt systems are like a fire hose compared with their 400-volt counterparts in that they allow the movement of far more electrons at the same current.
“Voltage is the diameter of your hose,” Miller said. “So if you have a 400-volt system, you have a proportionally smaller hose.”
Tesla is able to offer high rates of fast charging by jamming more current through its 400-volt system than competitors.
But that can put a lot of stress on EV batteries and charging stations.
For longevity, Miller said, moving to the next-generation 800-volt system further closes the fueling gap with ICE vehicles.
“From our perspective, we couldn’t deploy the same strategy as Tesla in the long term,” Miller said. “It wouldn’t be competitive for us.”
The E-GMP architecture is being used in Hyundai, Kia and Genesis vehicles.
While a few minutes of fast charging can add sufficient range for driving around town, the most common use likely for ultra-fast chargers now being deployed by public networks such as Electrify America is during road trips. That’s when longer charging sessions to fill EV batteries are more important.
