The results of our 2024 Kia EV9 DC fast-charging analysis are in. The 2024 Kia EV9 is one of the latest electric cars tested by State Of Charge at a 350-kilowatt DC fast charger. As in the case of other models, based on the Hyundai Motor Group’s E-GMP platform, we expected strong charging results—and indeed, the results are very good and in line with manufacturer specs.

Specs

State Of Charge tested the top-of-the-line Kia EV9 GT-Line trim. That’s a 6-seat version of the three-row SUV, which also has 7-seat versions in other trims.

The car is equipped with a 99.8-kilowatt-hour battery (552 volts nominal) and has an EPA Combined range of 270 miles. We also know that the EPA highway range is noticeably lower: 239 miles. The dual-motor, all-wheel drive powertrain has a peak system output of about 283 kilowatts (kW), which is enough to accelerate from 0 to 60 mph in 5.0 seconds.

Regarding AC charging, the car has a 10.9-kW onboard charger, which is expected to fully recharge the battery within roughly nine hours.

According to specs, DC fast charging from 10 to 80% state-of-charge (SOC) is possible in 24 minutes at up to 215 kW, as long as we have access to a high-power, high-voltage charger (like 350 kW, 800 V) and in optimum conditions. If only a 50-kW, 400-volt charger is available, the expected 10-80% SOC charging period would take 83 minutes.

As a side note, these charging specs concern all Kia EV9s with a 99.8-kWh battery. The entry-level Kia EV9 has a different 76.1-kWh battery, which –interestingly– has a higher voltage of 632 volts. It can also accept higher power levels of up to 236 kW. Because the pack is smaller and can charge at a higher power, its 10-80% SOC charging time is actually shorter at about 20 minutes (or 63 minutes at a 50-kW charger).

Charging Curve: The 0-100% SOC Test

Our DC fast-charging test was conducted at an EVgo charger rated at up to 350 kW. The charger’s maximum voltage of 950 volts and maximum current of 540 amps were both higher than requested by the car, which made us believe that we would see the Kia EV9’s full performance, without any limitations.

The first graph presents the charging power curve from 0% to 100% SOC. As you can see, charging power quickly increased to about 190 kW and remained relatively flat—around 200 kW between 9% and 59% SOC with a peak of about 214 kW. There are no signs of thermal throttling (also known as thermal derating), just a very solid charging curve.

Then, the power level started to decrease incrementally. At around 75% SOC, the power reduction became much smoother, but then again it leveled for some time between 85% SOC and 92% SOC at around 40 kW.

The final noticeable change was a gradual decrease in charging power with a quirk around 97-100% SOC. The charger basically showed 0 kW with maybe one amp of current for quite some time, but the charging session continued to 98%, 99%, and 100% SOC. We are not entirely sure what happened there. It might be related to battery cell balancing. It could also be that the car was fully charged but reported 97% SOC to the charger. This anomaly was ultimately unimportant because charging at the end was so slow (below 25 kW).

The average charging power between 10 and 80% SOC exceeded 180 kW.

C-Rate

Assuming that the car has a 100-kWh battery, the Kia EV9’s C-rate amounted to about 2C for most of the session (or up to about 60% SOC). It’s not the highest result in the industry, but it’s fairly ok.

Info: The C-rate indicates the correlation between the charging power and the battery pack capacity. A value of 1C would mean that the power value in kW is equal to the battery pack capacity in kWh and that at such power (current) rate, the battery would be fully recharged in 1 hour. The higher the C-rate, the higher the load on the battery and the faster it charges. A flat 2C would translate into a 30-minute charging session (0-100% SOC).

Charging Time

The full charging session from 0 to 100% SOC took almost 60 minutes. However, the part between 0 and 80% SOC was completed in 28 minutes. This means that it takes more time to recharge the remaining 20% of the battery than to recharge the first 80% of it.

The important 10-80% SOC window was completed in 24 minutes, which is in line with the manufacturer’s specs.

Range Replenishing Rate

Now let’s focus on the range replenishing rate, calculated using the rough battery capacity, charging power reported by the charger*, and range rating. The exact values of the range replenishing rate depend on the selected test cycle and its energy consumption (EPA Combined, EPA highway, or other).

*Part of the total charging power is used by the car’s system for auxiliary purposes and thermal management of the battery. This means that the real charging power is slightly lower, while the range replenishing rates in the graph might be slightly inflated.

As shown below, the Kia EV9’s range replenishing rate never exceeds 10 miles per minute of charging for the EPA Combined test cycle (at 270 miles of range). Its peak is actually somewhere around 9 miles/minute. Overall, it’s not a bad result, although not as high as for other smaller and more efficient vehicles.

The range replenishing speed slowed down considerably after about 75% SOC, and after 80% SOC, it entered the area of less than 3 miles/minute. That’s where we strongly advise users to stop charging unless it’s absolutely required to reach another charging point or destination.

Regarding the average range replenishing rate, the Kia EV9 can replenish about 84 miles of the combined EPA range (8.4 miles/minute) within the first 10 minutes of charging.

The second 10-minute portion is even better at 86 miles of range added (8.6 miles/minute). The third 10-minute portion reveals a slowdown to 5.0 miles/minute, and after that, the rate of range replenishment is too slow to be worth sitting at a DC fast charger.

How Long To Add Driving Range

Alternatively, we could ask how long it would take to add a certain number of miles. In the case of the EPA Combined test cycle, it took over 6 minutes to replenish 50 miles of range. After 12 minutes, the car would be able to cover about 100 miles.

Staying at the charger for 18 minutes would translate into 150 miles of range, and within 25 minutes, 200 miles out of 270 miles total would be replenished.

There is no point in charging longer, as adding another 50 miles would almost double the time spent charging.

DC Fast-Charging Matrix

The DC fast-charging matrix below summarizes the 2024 Kia EV9 GT-Line test charging session. It lists several main parameters: time, average charging power, the number of replenished SOC percent points, kWh of battery capacity, and miles of EPA Combined range added between certain starting and final SOC points.

As we can see, most of the boxes are green, which means that they are within 20% of the peak value. That’s a sign of a very flat charging curve around top values. The more yellow and red colors at a higher SOC indicate a slowdown of the charging process.

Please remember that the results might differ depending on a variety of factors, including the starting point of the session (which could shift the charging curve), charger, temperatures (ambient, that of the charger and its cable, and battery), and car (exact version, age, battery state-of-health, and software version).

Summary of Our 2024 Kia EV9 DC Fast-Charging Analysis

The 2024 Kia EV9 GT-Line appears to have rock-solid DC fast-charging performance within the popular 0-80% state-of-charge (SOC) window. The 10-80% SOC charging time of 24 minutes matched the manufacturer’s specs, making it one of the best results in the industry.

Because of the relatively flat charging curve up to about 70% SOC and no signs of thermal throttling, users can assume that they can add roughly 8 miles of driving range per minute of charging. At higher SOC, especially above 80%, the charging power decreases to a level at which it’s not worth continuing charging unless required.

Please remember that the Kia EV9’s battery has a higher nominal voltage of about 552 volts (or 632 volts in the case of the smaller battery version), and the same performance will not be available at low-voltage chargers of up to 500 volts DC. This might include many Tesla Superchargers, which will soon be available to Kia EV drivers.