VW ID.4 (2021): Analysis of the charging curve for fast charging

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C-rates, charging time, range reloading and more

VW ID.4 (2021): Analysis of the charging curve for fast charging-2021

The version with the 82 kWh battery of the VW ID.4 should bring 125 kW charging power with direct current. But is that also realistic? We analyze the fast charging capabilities based on data that InsideEVs USA obtained during a test at an Electrify America charging station won on a cold day.

Decrease in charging power with increasing SOC

Let’s take a look at the charging curve first. It is quite flat, the highest charging power (127-128 kW) remains constant for a long time after charging has started, before it begins to drop gently from around 30% SOC.

At 70 to 80 percent, a charging power of 65 kW is still achieved. Then the curve drops quickly and drops below 50 kW:

VW ID.4 (2021): Analysis of the charging curve for fast charging-curve

Average charging time for 20-80%

Now let’s see how the charging process is timed. The green curve in the diagram shows that charging from 20 to 80 percent takes about 31 minutes.

VW ID.4 (2021): Analysis of the charging curve for fast charging-fast

Average charging power at 20-80%

The average power when charging from 20 to 80 percent is 91 kW, or 71 percent of the maximum value – a very good result.

VW ID.4 (2021): Analysis of the charging curve for fast charging-analysis

C rates over the course of the loading process

An important parameter when loading is the maximum C-rate *. The C-rate indicates how the charging power relates to the total capacity of the battery. For example, the C-rate is 1 (usually given as 1C) if a 50 kWh battery is charged with 50 kW so that it is full after one hour. At 2C the battery would be full in half an hour, for which 100 kW charging power would be required.

With the ID.4, the maximum C-rate (i.e. the charging power in relation to the total battery capacity of 82 kWh) is around 1.56C. The average C-rate when charging from 20 to 80 percent is 1.1 C..

VW ID.4 (2021): Analysis of the charging curve for fast charging-C-rates charging time range reloading

How fast is the range recharged??

How much range a car can recharge per minute depends on its power consumption and the power consumption in turn depends on the application. There is both the WLTP range for the European version and range figures according to EPA for various types of routes. This is how we can calculate results for different scenarios:

  • WLTP
    A power consumption of 148 watt hours per kilometer is calculated from the WLTP range of 520 km and the available battery capacity of 77 kWh. When charging from 20 to 80 percent, an average of 91 kW is charged (see above); 148 Wh / km are 8,880 watt minutes per km. If we divide the 91,000 W by the 8,880 Wmin / km, the result is 10.2 kilometers per minute.
  • EPA (combined range)
    Taking into account the EPA combination range of 402 km (250 miles), the power consumption is 308 Wh / mile (191 Wh / km). The effective average speed of range replenishment when charging from 20 to 80 percent is then 4.9 miles / minute (7.9 km / minute).
  • EPA (Highway)
    From the EPA highway range of 370 km (230 miles), the power consumption is calculated at around 208 Wh / km (334 Wh / mile). When charging from 20 to 80 percent, 4.5 miles / minute (7.3 km / minute) are then reloaded.

Depending on whether you drive more cautiously (WLTP) or on the motorway (EPA Highway), here are the expected speeds for reloading range:

VW ID.4 (2021): Analysis of the charging curve for fast charging-curve

Comparison with the VW ID.3

VW ID.4 (2021): Analysis of the charging curve for fast charging-C-rates charging time range reloading

VW ID.3 and ID.4

Comparison of the charging performance

We are comparing the ID.4 (82 kWh) with the ID.3 (62 kWh), whose charging properties we recently analyzed based on the data published by Fastned. The shape of the quick charge curve is very similar, but the larger battery simply has a higher maximum charge capacity:

VW ID.4 (2021): Analysis of the charging curve for fast charging-fast

Comparison of the C rates

Both batteries appear to charge similarly, as the C-rate results are similar:

VW ID.4 (2021): Analysis of the charging curve for fast charging-analysis

Compared to range reloading

When the range is recharged – only for the WLTP test cycle – it turns out that the ID.4 restores the range faster than the ID.3, despite a slightly higher energy consumption. This is due to the larger battery, which allows for faster charging. Equipped with the same battery as the ID.4, the ID.3 would be slightly ahead.

VW ID.4 (2021): Analysis of the charging curve for fast charging-curve

More about fast charging: VW ID.4 (2021): Analysis of the charging curve for fast charging-C-rates charging time range reloading Mercedes EQV: How quickly does the electric V-Class charge with direct current?

VW ID.4 (2021): Analysis of the charging curve for fast charging-charging Lucid Air should charge twice as fast as the Porsche Taycan

Remarks:

* Some values ​​in the charts are estimates from the data source.

** The ambient temperature during the ID.4 test was around 5 degrees Celsius.

*** The temperature of the battery cells could have a very negative effect on the charging capacity. We have no data on the temperatures of the battery at the beginning and during the charging process. At low or high temperatures and after very dynamic driving, the charging power can be significantly lower than indicated in the diagrams (in extreme cases charging can even be completely impossible).

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