Supercharger reality: 700 A at 500 V
If the 500 A problem says a 400 V car cannot exceed about 195 kW, how does a Tesla Model 3 hit 250 kW at a Supercharger?
Because Tesla did not build a 500 A cabinet. V3 and V4 cabinets push roughly 700 A, and they top out at about 500 V. That is the opposite trade from a CCS high-power cabinet, which does 500 A at up to 1000 V.
Typical 350 kW CCS cabinet: 500 A, 1000 V
Tesla V3/V4 cabinet: 700 A, 500 VFor a 400 V Tesla, this is excellent
700 A into a 355 V pack is 249 kW. The car’s curve, not the cabinet, becomes the limit, which is the comfortable way round. In the calculator a Model 3 does 10 to 80% in about 23 minutes at a Supercharger and peaks at 243 kW, against 24 minutes and 180 kW on a “350 kW” CCS stall.
Note what did not happen. The peak went up by a third and the session got barely a minute shorter. Past about seventeen minutes the car’s taper has taken over and the cabinet stops mattering at all. Peak power is a headline; area under the curve is a journey.
For an 800 V car, it is the mirror of the 500 A problem
An 800 V pack sits at 650 to 800 V. A 500 V cabinet cannot reach it. There is no clever firmware fix: the cabinet physically cannot produce the voltage the pack needs.
What happens instead is that the car splits its pack into two halves in series-parallel, or runs an internal boost converter, and accepts a fraction of its rated power:
| Vehicle | On an 800 V cabinet | On a 500 V cabinet |
|---|---|---|
| Hyundai Ioniq 5 | 260 kW | about 90 kW |
| Kia EV6 | 235 kW | about 90 kW |
| Porsche Taycan | 320 kW | about 150 kW |
| Lucid Air | 300 kW | about 50 kW |
An Ioniq 5 at a Supercharger is a flat 90 kW line for 37 minutes. The same car on a proper 800 V cabinet is done in 17. The adapter fits. The electrons do not care.
The lesson for siting
There is no universally best cabinet, only a best cabinet for a fleet. High current suits 400 V cars; high voltage suits 800 V cars. A site serving both wants cabinets that can do both, which is why modern high-power units advertise a wide voltage window and 500 A or more, and why the megawatt charging standard for trucks specifies 1250 V and well over 1000 A.
Next
C-rate, not kilowatts
A megawatt sounds enormous until you divide it by 850 kWh. Why the Tesla Semi still needs half an hour, and why an air taxi charges harder than any car.