In the second part of our DC fast-charging analysis of the 2024 Chevrolet Silverado EV RST, we will focus on the 0-100% state-of-charge (SOC) test and compare it with the previous State Of Charge’s 10-80% SOC test side-by-side. To some degree, it is an extended version of the previous article. In both cases, the vehicle was charged at a 350-kilowatt DC fast charger.

The main conclusion of the article is that the Chevrolet Silverado EV’s DC fast-charging results match specs and are very good in terms of range replenishing speed.

Specs

State Of Charge’s test concerns the top-of-the-line 2024 Chevrolet Silverado EV RST First Edition trim. In the 2024 model year, Work Truck (WT) versions also exist for businesses.

General Motors does not reveal the battery capacity of the Chevrolet Silverado EV, but we know that it’s more than 200 kilowatt-hours thanks to its 24-module battery. An interesting detail of note is that the battery consists of two 400-volt parts, connected in parallel. However, when DC fast charging, these two parts are switched to a series connection, which doubles the voltage to roughly 800 volts and enables high-power charging at half the current.

The EPA Combined range of the Chevrolet Silverado EV RST First Edition is 440 miles. During State Of Charge’s 70 mph range test, the truck marginally exceeded this number, reaching 441.4 miles. With a dual-motor all-wheel drive powertrain (over 560 kilowatts), the Chevrolet Silverado EV RST can accelerate from 0 to 60 mph in just 4.5 seconds.

The onboard charger is 19.2 kW, which in most cases should be enough to fully recharge the truck overnight.

According to its specs, DC fast charging can replenish up to 100 miles of range in 10 minutes at a 350-kW high-voltage charger. The manufacturer does not reveal charging times for popular state-of-charge (SOC) windows, like 10-80% or 20-80% SOC. The charging speed will be significantly lower at a 400- to 500-volt charger.

Charging Curve: The 0-100% SOC Test

Our DC fast-charging tests were conducted at an EVgo charger rated at up to 350 kW. The charger’s maximum voltage of 950 volts was higher than requested by the vehicle. However, the charger’s maximum current of 540 amps appeared to be available only at the beginning (below 650 volts). It then gradually decreased through the session, limiting the vehicle’s peak charging performance to the charger’s peak of 350 kilowatts. For reference, at 5% SOC, the 346 kW power level was achieved at 716 volts and 483 amps (out of 484 amps available from the charger). The vehicle’s peak charging power level might be slightly higher than our 347 kW at a charger with a higher current output.

The first graph below presents the charging power curve from 0% to 100% SOC. The charging power very quickly increased to its peak level of nearly 350 kW and remained relatively flat until around 22% SOC. After a step change, the vehicle charging continued at about 290-300 kW from about 24% to 36% SOC.

At that point, it seems that some serious thermal throttling (also known as thermal derating) kicked in, and the charging power significantly decreased to just under 150 kW at about 46-47% SOC. After hitting the local bottom, the charging power gradually increased back to over 200 kW at 69-74% SOC, thanks in part to the increase in battery pack voltage but also the increase in charging current.

The final part (after 74% SOC) showed a typical, gradual decrease of charging power from 100 kW at 83% SOC, 50 kW at 95% SOC, and roughly 20 kW at the very end of the session.

Overall, the charging curve is good and shows very high charging levels. However, it appears that the vehicle’s battery cooling capabilities are not strong enough to remain charging at maximum power for the full session (at least until about 60-70% SOC, when other limitations come into play).

According to the EVgo charger, the vehicle consumed 237 kilowatt-hours of energy during the charging session, including losses and energy for cooling and auxiliary loads.

If we compare the 0-100% SOC charging session with a 10-80% SOC charging session, we will see a very interesting outcome: both charging curves are similar. The 10-80% SOC merely shifts because it starts at 10% SOC.

After the initial 340-350 kW charging platau, there is a step change to about 300 kW and the second platau. At some point, thermal throttling began to bring the charging power down to just under 150 kW. The length of the 300-kW portion of the test is longer, while the derating proved shorter than in the case of 0-100% SOC session. We assume that the main reason for this is the higher voltage and lower current in the shifted 10-80% SOC session. It simply puts lower strain on the battery’s cooling system when charging at 300-350 kW at a higher SOC because the current is lower.

C-Rate

We don’t know the Chevrolet Silverado EV’s exact battery capacity, but assuming roughly 210 kWh for the purposes of estimation, we determined the C-rate to be about 1.6C. It’s not a high value, but it seems that electric pickups usually don’t have the highest C-rates.

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 over 98 minutes. This is largely because of the relatively low charging power received at the end of the session, including about 6 minutes spent at 100% SOC, which was probably used to balance the battery cells. However, we must remember that the charging session is also long because the battery pack is huge.

The 0-80% SOC window took about 52 minutes. This means that the 80-100% SOC charge time is 46 minutes.

When comparing the results with the 10-80% SOC session, it turns out they are very similar. In both cases, the high charging power level of 290-350 kW is available for about 20 minutes, after which charging slows down.

Range Replenishing Rate

Considering the Chevrolet Silverado EV RST First Edition’s EPA range of 440 miles (and 441.4 miles in the 70 mph range test), its range replenishment rate peaks at about 10 miles per minute.

Chevrolet promised up to 100 miles in 10 minutes. Our test showed an average of 10.0 miles per minute over the first 10 minutes, which exactly matches the specs.

The second 10-minute period was slightly slower (8.3 miles per minute), and after that, the charging rate dropped to several miles per minute. The worst part came after 50 minutes. It’s not worth sitting at a DC fast charger at that point.

The 10-80% SOC test had a slightly higher range replenishment rate. It peaked at 10.2 miles/minute in the first 10 minutes (102 miles of range replenished) and continued strong in the second 10-minute period at 9.2 miles/minute (with an additional 92 miles added).

Thanks to its very high charging power and a long range of 440 miles, the Chevrolet Silverado EV replenishes its range faster than the Kia EV9 we previously analyzed (which replenished at 8.4-8.6 miles/minute).

How Long To Add Driving Range

Alternatively, we could ask how long it would take to add a certain number of miles. Our test showed that the first 50 miles of driving range can be replenished in just over 5 minutes. After 10 minutes, the vehicle can drive another 100 miles.

To add 200 miles of range, the 2024 Chevrolet Silverado EV RST First Edition needs to be plugged in for just 23 minutes. After 43 minutes, we should be able to go another 300 miles; after 52 minutes, an additional 350 miles might be possible.

There is no point in charging longer, as adding 400 miles would require 70 minutes or so spent charging, and recuperating the full 440-mile range could mean being plugged in for more than 1.5 hours.

The 10-80% SOC session was slightly faster regarding replenishing the range. Two hundred miles were added in just over 20 minutes, compared to 23 minutes in 0-100% SOC session. The difference for 300 miles is even bigger — 38.5 minutes versus 43 minutes.

DC Fast-Charging Matrix

Now it’s time for the DC fast-charging matrix, which summarizes the 2024 Chevrolet Silverado EV RST First Edition 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, there are three main colors used to indicate the average power used out of what is potentially available — light/dark green, yellow, and orange/red. This means that only the initial part of the session is very fast. Then we have a moderate period, and after 80% SOC, the charging speed is rather slow.

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).

Here is the same matrix, but for the 10-80% SOC session. Since the charging curve shifted, so did the matrix.

Summary of Our 2024 Chevrolet Silverado EV RST DC Fast-Charging Analysis

The 2024 Chevrolet Silverado EV RST First Edition has pretty strong DC fast-charging capabilities. The test confirmed its ability to replenish 100 miles of range in 10 minutes, and we almost achieved the 350-kW peak power (it seems that the charger was the bottleneck here, as the potential peak power was 360+ kW).

The charging curve had a nice initial plateau, but it was later hit by thermal throttling (thermal derating), which noticeably affected the results. It seemed that the fastest charging speed was only available for the first 15 to 20 minutes.

The results were better when starting at 10% SOC rather than at 0% SOC. Probably because the voltage and current impact the charger’s constraints and losses/cooling issues. At least, that’s what we think. If true, it’s better to plan the next charging stop at 10, 15, or 20% SOC rather than at 0 or 5% SOC — one will not lose the range replenishing rate while maintaining a higher safety margin. Twenty-minute stops would be the most fruitful.

The key strong point of the Chevrolet Silverado EV is its huge battery, which is north of 200 kWh and has a combined EPA range of 440 miles. Because of that, it can replenish a lot of range very quickly — like 250+ miles in roughly half an hour, even though the pickup’s overall efficiency is far behind that of other electric cars. On the other hand, the full charging session takes longer, and charging results might be significantly weaker at 400-500-volt chargers.

Other than that, Chevrolet still has some potential for upgrades. The battery’s C-rate is not too high, which leaves space for higher peak power (400 kW, maybe). An even more critical upgrade would be a reduction in thermal throttling.

As usual, at higher SOC levels (especially above 80%), the charging power decreases to a level where it’s not worth continuing charging unless absolutely required.