Kia EV6 Prototype Fast Charging Analysis: Very Fast But Quirky

Today we will take a look at the fast charging capability of a pre-production prototype of the upcoming Kia EV6, which earlier this month was tested by Out of Spec Reviews‘ Kyle Conner in Germany.

The Kia EV6 is based on the same E-GMP platform as the Hyundai Ioniq 5, which is a fast charging titan, so we expect a similarly great performance from the EV6 as well.

However, the Kia EV6 has a different battery than the European Ioniq 5 (77.4 kWh according to Kia). The all-wheel-drive car is expected to offer a WLTP range of 506 km (314 miles). The rear-wheel-drive version should be able to go about 4% further on a single charge – 528 km (328 miles).

Kyle Conner conducted multiple tests at IONITY fast chargers, noting a highly volatile charging curve (even more volatile than in the Hyundai Ioniq 5). The first one, on which we will focus, is the 0-100% State of Charge (SOC) test with a pre-conditioned battery temperature. The second one in the video, starts at 40% SOC.

Let’s get into details.

Charging power vs state-of-charge (SOC)

The test reveals that the charging power almost immediately starts to increase above 200 kW, before even reaching 2% SOC. That’s really awesome, especially since the highest power output was maintained up to about 46% SOC.

The peak charging power is about 233 kW (we even saw 234 kW for an ultra short while).

The things get complicated after at 46% SOC, when the power output starts to decrease – in instant steps – reaching about 186 kW at 47% SOC, then 116 kW at 58% SOC and finally 30 kW at 63% SOC. That’s an extraordinary sight.

Not only that. Then, the power output increases in a very short time up to over 191 kW at 66% SOC, and starts to decrease more linearly from then. Around 78% SOC it hits a 62 kW dip, and another one of just 6 kW at 82 SOC.

The good thing is that even at 92% SOC, the power was above 50 kW, and about 20 kW at 98% SOC.

We assume that the hardware and software in the pre-production prototype of the Kia EV6 is simply raw and over-sensitive to temperatures inside the battery pack. If Kia manages to smooth the charging curve, so it would gradually decrease from 46% SOC, it will be one of the best on the market right now.

As the tested Kia EV6 is a prototype, we will take a look only at the comparison with the Hyundai Ioniq 5 (72.6 kWh battery version) – the one tested by Battery Life and by Hyundai itself (demo).

Let’s note also that the U.S. version of the Hyundai Ioniq 5 will have the same battery capacity as the Kia EV6 (77.4 kWh), while in Europe there are two other versions (58.2 and 72.6 kWh).

Comparison of charging power

We complained a little bit about the dips in the Hyundai Ioniq 5’s charging curve, but in the pre-production prototype of the Kia EV6 it’s even worse.

On the other hand, the EV6 has  much better charging output in the beginning! Assuming that the red line will be smoothened, the Kia EV6 has clear potential to beat the Hyundai Ioniq 5.

As of today, the average power in the 20-80% SOC window is better in the Hyundai Ioniq 5:

DC Fast Charging Comparison by InsideEVs
Model
[data source]
Drive /
Battery
(kWh)
Max
Power
Avg
Power
(20-80%)
2021 Kia EV6 Prototype (77.4 kWh, AWD)
[Out of Spec Reviews]
AWD
82 kWh
233 kW 151 kW
2021 Hyundai Ioniq 5 (72.6 kWh)
[Battery Life]
AWD
77 kWh
224 kW 170 kW
2021 Hyundai Ioniq 5 (72.6 kWh) (Hyundai’s demo)
[Hyundai]
AWD
77 kWh
225 kW 180 kW

Comparison of C-rate

The C-rate comparison is tricky, as we don’t know for sure the total battery capacity number, but it appears that they are comparable.

DC Fast Charging Comparison by InsideEVs
Model
[data source]
Drive /
Battery
(kWh)
Max
Power
Avg
Power
(20-80%)
Max
C-Rate
Avg
C-Rate
(20-80%)
Time
(20-80%)
2021 Kia EV6 Prototype (77.4 kWh, AWD)
[Out of Spec Reviews]
AWD
82 kWh
233 kW 151 kW 2.8 1.9 18 min
2021 Hyundai Ioniq 5 (72.6 kWh)
[Battery Life]
AWD
77 kWh
224 kW 170 kW 2.9 2.2 15 min
2021 Hyundai Ioniq 5 (72.6 kWh)
(Hyundai’s demo)
[Hyundai]
AWD
77 kWh
225 kW 180 kW 2.9 2.3 15 min

Comparison of range replenishing speed

The Kia EV6 replenishes range faster than the Hyundai Ioniq 5, but then is affected by the quirks in the charging curve.

Overall, in the 20-80% SOC window, Kia EV6 is slower than the Hyundai Ioniq 5, but with a potential to be quicker in the final production version.

DC Fast Charging Comparison by InsideEVs
Model
[data source]
Drive /
Battery
(kWh)
Avg
Power
(20-80%)
WLTP range
rep. rate
(20-80%)
2021 Kia EV6 Prototype (77.4 kWh, AWD)
[Out of Spec Reviews]
AWD
82 kWh
151 kW 16.5 km/min
10.3 mi/min
2021 Hyundai Ioniq 5 (72.6 kWh)
[Battery Life]
AWD
77 kWh
170 kW 18.8 km/min
11.7 mi/min
2021 Hyundai Ioniq 5 (72.6 kWh) (Hyundai’s demo)
[Hyundai]
AWD
77 kWh
180 kW 19.9 km/min
12.4 mi/min

Conclusions

Overall, the Kia EV6 in its pre-production prototype version appears to be a diamond that needs to be polished. The charging results are already very good.

If the manufacturer will tweak the charging system, which is probably over-sensitive to battery temperatures (or voltage), it should become state-of-the-art in terms of charging speed, at least on par with the Hyundai Ioniq 5.

We look forward to test and analyze the final product that in Europe and South Korea will be delivered to customers later this year (in the U.S. in Q1 2022).

2021 Kia EV6 Prototype (77.4 kWh, AWD) :: DC Fast Charging Summary by InsideEVs
Drive: AWD; Battery pack (net / total): 77.4 / 82 kWh
[Data source: Out of Spec Reviews]
Peak Power
Peak C-rate

Average Power (20-80% SOC)
Average-to-Peak Power
Average C-rate (20-80% SOC)

Time (20-80% SOC)

233 kW
2.8

151 kW
64%
1.9

18 min

Range Replenishing Speed (Average 20-80% SOC):
WLTP 16.5 km/min (10.3 mi/min)

General info:

* Some values on the charts are estimated from the data source.

** Temperature of the battery cells might highly negatively affect charging capabilities. We don’t have data about temperatures of the battery at the beginning and during the charging process. In cold or hot weather, as well as after driving very dynamically, charging power might be significantly lower than shown on the charts (in extreme cases charging might be impossible until the battery temperature will not return to an acceptable level).


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