In-depth analysis includes results of DC fast charging from 0-100% and comparison of data for three different ID.4 cars.

We are back with an extended in-depth analysis of DC fast charging of the Volkswagen ID.4 1ST, which amazes us not only with the charging performance but also consistency.

Today we will focus on a new test - from 0 to 100% State of Charge (SOC) - conducted by our colleague Kyle Conner from Out of Spec Reviews and InsideEVs YouTube channels. Additionally, we will compare the results with the previous test by Tom Moloughney and data released by Fastned, a European charging network. Three ID.4 cars in total.

Kyle's test concerns the Volkswagen ID.4 1ST (82 kWh battery version and RWD). Because the battery thermal management system tries to keep the cells at a temperature of about 25°C (77°F) all the time, there is no need for pre-conditioning. Almost all electric loads were off during the charging session (besides a minor load of heated front seats).

Charging power vs state-of-charge (SOC)

Charging of the Volkswagen ID.4 starts at a power level close to its peak of about 127 kW, which is maintained up to roughly 30% SOC.

Then the charging curve gently fades, reaching about 65 kW at 70% SOC. This level is maintained up to over 80% SOC. After a certain point, the power drops again in stages, but overall it's still nearly 40 kW at 90% SOC and at 30 kW at 97-98% SOC. A very strong result.

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State-of-charge (SOC) vs time

Charging from 20% to 80% SOC took about 31 minutes.

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Average charging power vs state-of-charge (SOC)

The average power in the very important range from 20% to 80% SOC is 90 kW, which is 71% of the peak value. A very good result.

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C-rate vs state-of-charge (SOC)

The peak C-rate* - charging power in relation to the total battery capacity of 82 kWh - is about 1.55C.

The average C-rate when charging from 20% to 80% SOC is 1.1C.

*C-rate tells us how the charging power relates to the battery pack capacity. For example: 1C is 1-hour charging power (current), when the power value in kW is equal to the battery pack capacity in kWh. 2C would be enough to recharge in half an hour.

The net battery capacity of 77 kWh is about 94% of the total battery capacity.

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Range replenishing speed vs state-of-charge (SOC)

The rate of replenishing range depends on the energy consumption and the energy consumption depends on the use case.

For ID.4 (82 kWh), we have numbers for several test cycles and also our very own IEVs 70 mph range test result, conducted by Tom Moloughney. Let's take a look at the results:

  • WLTP
    Taking into consideration the WLTP range of 520 km (323 miles) and available battery capacity of 77 kWh, we can assume energy consumption of 148 Wh/km (238 Wh/mile).The effective average speed of range replenishing when charging from 20% to 80% SOC would be 10.1 km/minute (6.3 miles/minute).
  • EPA Combined range
    Taking into consideration the EPA Combined range of 250 miles (402 km) and available battery capacity of 77 kWh, we can assume energy consumption of 308 Wh/mile (191 Wh/km).
    The effective average speed of range replenishing when charging from 20% to 80% SOC would be 4.9 miles/minute (7.8 km/minute).
  • EPA Highway range
    Taking into consideration the EPA Highway range of 230.2 miles (370 km) and available battery capacity of 77 kWh, we can assume energy consumption of 334 Wh/mile (208 Wh/km).
    The effective average speed of range replenishing when charging from 20% to 80% SOC would be 4.5 miles/minute (7.2 km/minute).
  • IEVs 70 mph range test
    Taking into consideration the IEVs 70 mph range test result of 234 miles (377 km) and available battery capacity of 77 kWh, we can assume energy consumption of 329 Wh/mile (205 Wh/km).
    The effective average speed of range replenishing when charging from 20% to 80% SOC would be 4.6 miles/minute (7.3 km/minute).

Depending on whether your use case is more gentle driving (WLTP) or rather more highway driving (IEVs 70 mph range test / EPA Highway), here is the expected range replenishing speed:

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Ultimate DC fast charging card

The regular readers of IEV know that most recently we have developed an Ultimate DC fast charging card. The initial version of the matrix has consisted data from Tom's DC fast charging test, while the new one, attached below, is for the full 0-100% SOC range, based on Kyle's test.

Moreover, this time, we adjusted the range values to the IEV's 70 mph range test.

The Ultimate DC fast charging card shows an estimated time of charging to add a certain number of SOC percent points, average charging power, added energy and added range for listed SOC ranges. Click here to enlarge the image.

The amount of information included in this single chart is very high - for example, the last box in each row represents a 10% SOC step (0-10%, 10-20%, 20-30%...), which directly tells what time is required to add an additional 10% SOC. Others might be interested to see 20-80% or 10-90% values, or a general visualization of consistency (a color map).

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General info: The matrix above, might be helpful from the user perspective, but be aware that it's just an estimate from a particular test, with measure and calculation uncertainty probably at least 3%. On top of that comes variation for individual case - car (version, age/battery state-of-health), charger, ambient and battery temperature, software version and more (including cabin heating/cooling during charging).

Because of the Volkswagen ID.4 charging consistency (see the next part of the article), we strongly believe that this card can be used to plan a long-distance trip or to explain the expected charging time to potential buyers/new users.

Comparisons with other ID.4 tests

Volkswagen ID.4

Comparison of charging power

And now, a very important comparison of the Volkswagen ID.4 (82 kWh battery version) DC fast charging results of three different cars.

We have here data from three completely different charging sessions:

Three different ID.4 cars, three different chargers, three different people, three different days and conditions, as well as three different starting points.

The biggest positive surprise is that basically nothing has changed in the results!

The peak values and overall shape are the same. There are only small differences, that are probably mostly related to the accuracy of measurement/data reading (from videos/charts) than to the actual real difference of the charging performance.

We can assume that the consistency is so high thanks to the battery thermal management system and very similar temperature of the cells inside the pack. With such an approach, there is also no shifting of the charging curve on the SOC-axis, depending on the starting point.

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Conclusions

The conclusion from the final DC fast charging test of the 2021 Volkswagen ID.4 (82 kWh) is very positive.

The charging curve and peak value are good and it seems that drivers will be able to get such results consistently.

We look forward to testing more EVs and comparing them to the Volkswagen ID.4/MEB-based models.

General info:

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

** 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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