The all-new 2024 Chevrolet Equinox EV entered the US market in Q2 2024 with the first 1,000+ deliveries. This opened the way for detailed tests. After the initial 70 mph range test, our very own Tom Moloughney has just released his 2024 Chevrolet Equinox EV DC fast-charging analysis— specifically the front-wheel drive 2RS version, although all types have the same battery system.

While no one expected the Chevrolet Equinox EV to be a charging speed demon, the test results are a bit disappointing. That’s because of the car’s quirks, which require some explanation.

 

 

Specs and Low-Voltage Battery

The front-wheel drive 2024 Chevrolet Equinox EV has an EPA Combined range of 319 miles. Its battery pack is believed to have a usable capacity of roughly 85 kilowatt-hours, consisting of ten Ultium battery modules of about 8.5 kWh each.

According to the manufacturer, the car can DC fast charge at up to 150 kilowatts peak, while its best range replenishing rate is up to 70 miles of driving range in 10 minutes. This means that even at peak charging power, the car’s battery will remain well under a 2C charging rate, which is significantly behind that of the top EVs.

The key specification of the Chevrolet Equinox EV’s battery is its nominal voltage of 288 volts. At low state-of-charge (SOC) it’s under 270 volts, and exceeds 330 volts at the top end. Such an unusually low voltage battery configuration puts a lot of strain on the DC fast charger, which must operate at relatively high current levels.

For example, to supply 150 kW of power at 288 volts, the charger would have to send over 520 amps, which might be above the charger’s capability. This means that in some cases, the charging power will be limited not by the charger’s power peak –there are many 150+ or even 350-kW chargers– but by the charger’s current peak. Thus, the 150-kW charging level will not be seen too often or only for a specific part of the charging session at ultra-high-power chargers with a high current limit.

By the way, the onboard charger of the Chevrolet Equinox EV is 11.5 kW in the base version, which is enough to replenish 34 miles of range in 60 minutes, according to Chevrolet. There is also an optional 19.2-kW charger which can add up to 51 miles of range within the same one-hour time. Both types are good enough to fully recharge the car overnight (or in several hours, in the case of the 19.2-kW version).

 

Charging Curve: The 0-100% SOC Test

State Of Charge tested a Chevrolet Equinox EV 2RS FWD at two DC fast chargers –a 350-kW EVgo charger and a 150-kW Electrify America charger– and at various start and final SOC levels. In the first part of this article, we will focus on the 0-100% SOC charging sessions.

At first sight, 150 kW should be just good enough for a vehicle with a 150 kW peak charging capability. One might not expect to notice any improvement on the 350-kW charger. However, as we will see in the video, the issue in the case of low-voltage batteries is the 350 amp current limit on the 150-kW charger.

This is why once the session started, the Chevrolet Equinox EV could not get 150 kW of charging power at the 150-kW charger. It barely started at 91 kW. On the other hand, the 350-kW charger with an output of up to 540 amps could start the session from 132 kW (496 amps at 267 volts). In this case, the limit appears to be on the car’s side (500 amps).

 

 

As the voltage increased through the charging session, the charging power hit 150 kW (498 amps at 301 volts) at 7% SOC using the 350-kW charger. The power even exceeded the 150-kW level for some time (154 kW at 18% SOC). On the other hand, at the 150-kW charger, the current limit kept the power output below 100 kW (94 kW at 10% SOC).

At that point, the more powerful 350-kW charger seemed to easily win the charging race. However, another Chevrolet Equinox EV’s specification comes into play after just about 8:30 minutes of charging. Around 20% SOC at the 350-kW charger, the power level was cut significantly— most likely due to thermal derating of the battery system. At 25% SOC, the power level was 75 kW. At 29% SOC, it was just 63 kW (214 amps at 299 volts). From that point, the charging power gradually improved (mostly thanks to increasing voltage), but it never recovered to the peak level, not even to 100 kW.

Meanwhile, the 150-kW charger continued to do its job at a power level between 90 to 100 kW up to almost 45% SOC, partially catching up with the 350-kW charger. There was only relatively slight thermal derating in the middle of the session.

The main conclusion here is that if one will DC fast charge the Chevrolet Equinox EV at its maximum capabilities, the battery’s temperature might increase to a level that requires it to slow down after several minutes. Because the model is new on the market, there is a chance that this issue will be addressed through a future software update.

 

 

After about 75-80% SOC, the charging power gradually decreases from about 80-90 kW, which is typical in many EVs due to battery limitations. Because of that, it’s never advised to stay at a DC fast charger beyond 90% SOC (or even beyond 80% SOC) unless it’s absolutely critical to reach one’s final destination. It’s simply a waste of time.

Overall, the 0-80% SOC charging time of the Chevrolet Equinox EV was similar on both chargers. At the 350-kW charger, it took over 50 minutes, while it took 53 minutes at the 150-kW charger. The difference is very small, as the 350-kW charger lost most of its initial advantage due to the battery’s thermal limit. EV drivers should then not bother to search for a higher-power charger.

Tom described the DC fast-charging capability as “not good”, but also “not horrible” (there are worse EVs). Nonetheless, 50-53 minutes is a long time to get to 80% SOC.

The charging time is much longer for a full session time (0-100% SOC). Additionally, it’s surprisingly shorter at the 150-kW charger (103 minutes) compared to the 350-kW charger (107 minutes). However, there is no magic here. It simply seems that after charging at maximum capabilities at the 350-kW charger, the car’s computer decided to balance the battery cells for a prolonged time, staying connected at 100% SOC and a low power level (below 20 kW).

The total dispensed energy amounted to over 97 kWh at the 150-kW charger and over 100 kWh at the 350-kW charger.

Charging Curve: 20-80% SOC Test

Now let’s take a look at the DC fast-charging tests from 20% to 80% SOC at the same two 150-kW and 350-kW chargers.

In general, there are some similarities with previous tests (0-100% SOC). As we can see below, the 350-kW charger with high-current output was able to start charging at over 150 kW right away (496 amps at 306 volts). It maintained this high level up to 157 kW for a couple of minutes before gradually slowing down. At some point, the power was significantly limited to less than 70 kW at around 55-65% SOC.

Meanwhile, the 150-kW charger (limited to about 350 amps), was only able to supply over 110 kW, up to a 116 kW peak. However, this lower level was relatively stable up to roughly 60% SOC, after which the power output gradually decreased. The difference between 50 and 70% SOC allowed it to partially catch up with the 350-kW charger.

In other words, when charging from 20-80% SOC, we can see a kind of horizontally shifted 0-100% charging graph.

 

 

The 350-kW charger had an initial advantage, but the charging time from 20% to 60% SOC was similar— almost 20 minutes at the 350-kW unit and 21 minutes at the 150-kW unit. The 20-70% SOC time was pretty much identical at over 27 minutes, too.

Surprisingly, the full session from 20 to 80% SOC took 34 minutes on both chargers. Moreover, at 80% SOC, both chargers were supplying exactly the same power of 72 kW. This is another indication that until there is no solution for thermal derating, there is no sense in seeking higher-power chargers.

The whole situation reminds us of modern laptop computers in which the thermal power limit is the main bottleneck, rather than CPU or GPU computing power.

The 20-80% SOC charging session ended with 59.8 kWh dispensed by the 150-kW charger and 57.9 kWh by the 350-kW charger.

Comparisons

Here is a comparison of the DC fast-charging tests at the 150-kW charger, which differ slightly depending on the starting point. A start at 20% SOC allowed it to achieve over 110 kW of power, and the battery appears to have no issue with temperatures, which was the case when starting at 0% SOC where the session was longer.

 

 

DC fast charging at the 350-kW charger with a high current limit resulted in a similar thermal derating on the car’s battery side, regardless of the starting point— 0% or 20% SOC.

 

Charging Time

A quick look at the charging time necessary to achieve a particular SOC reveals that aside from the initial period (where the 350-kW charger has an advantage), there are no big differences.

The charging time might be the same or just a few minutes better, depending on the start/stop SOC and selected charger. Because of that, it appears to be better to use the nearest and most convenient location rather than the one with a higher power.

As we mentioned earlier, there is no sense in charging beyond 80% SOC (and definitely not beyond 90% SOC) unless it’s critical to reach one’s destination/next charging stop, because charging is very slow. At the end of the session, the car might enter battery cell balancing mode, which happened at 100% SOC at the 350-kW charger and took almost half an hour.

 

Range Replenishing Rate

Regarding the range replenishment speed, the manufacturer says that the car can replenish up to 70 miles in 10 minutes (or 7 miles in one minute). State Of Charge’s tests confirmed that this rate is possible for a short period of time at a charger, which can deliver 500 amps (the 350-kW one in our case). Otherwise, the peak range replenishment rate will reach an average of 5-6 miles per minute.

Nonetheless, for most of the session after the initial quicker part, the range replenishing rate varies between 4 and 5.5 miles per minute. After 80% SOC, it’s so low (a matter of 1 mile per minute) that it should not be used until absolutely needed.

The EPA Combined range of the car is 319 miles, while State Of Charge’s 70 mph range test resulted in 305 miles. The range replenishment rate was calculated for both values:

 

 

Additionally, here is the table with the time (in minutes) necessary to add a certain range — 50, 100, 150, or 200 miles. The good news is that most users will need just 7-10 minutes to add 50 miles of range.

If a higher boost is needed, then the charging time will increase. Replenishing 100 miles of range will probably take 13-21 minutes, depending on the charger and the starting point. To add 200 miles, drivers should be prepared to spend at least 40 minutes at a charger.

 

Summary

The 2024 Chevrolet Equinox EV is not a good DC fast-charging car –it’s behind many other crossover/SUV EVs on the market– but it’s also not horrible. It achieved the performance promised in the specs, both in terms of power of 150 kW and the average range replenishing rate of 70 miles in 10 minutes.

However, peak charging performance is only available at DC fast chargers with high current output (500 amps), which may not be possible at many 150-200-kW chargers. This is a direct consequence of a relatively low battery system voltage (about 288 volts nominal).

Another issue is thermal derating. It does not matter that much if a charger is high-power with high current output if the charging power will have to be cut in half to 75 kW or less after roughly 10 minutes. This one thing leveled the charging time of 20-80% SOC session at 150-kW and 350-kW chargers.

Drivers of the Chevrolet Equinox EV should not bother seeking a higher power charger if the charging time is similar at both. The only difference would be in a short 5-10 minute boost to get 50+ miles of range— then the 350-kW charger with high current output won slightly.

Finally, there is absolutely no sense in charging beyond 80% SOC because the charging power slows to a very low level. Do it only if it’s critical to reach your next charging stop or destination. We know that EV charging networks are aware of this issue and are even exploring 85% SOC charging limits.