Analysis of the Rivian R1T Charging System: From 0 to 100% State-Of-Charge

The Rivian R1T is the next electric car we'll look at because it can charge quickly.

The data comes from a test done by Kyle Conner for Out of Spec Reviews at an EVgo rapid charging station.

It's not the ideal charging session, as the battery appears to be slightly cold in the video, but it demonstrates the complete 0-100 percent state-of-charge (SOC) range. The results are superior to those obtained in a brief TFLEV test.

In a later part of the video, Kyle tried to explore other charging sessions to determine the theoretical peak charging characteristic, but our focus in only on the first session.

It's worth noting that for optimal results, the R1T must be charged using a charger capable of supplying up to around 450 A at above 400 V (for a peak of up to around 200 kW).

Let's crunch the numbers and see if the rapid charging results are as fantastic as the vehicle's total stats.

Charging power vs state-of-charge (SOC)

The charging curve is mostly flat up to about 58 percent SOC, based on data from the movie's 0-100 percent SOC test (the charger's screen).

The highest charging power was approximately 184 kW at approximately 16-17 percent state of charge, compared to the predicted 200 kW. Kyle was able to attain close to 200 kW in some of the other charging sessions.

The charging power is significantly reduced in the upper third. At approximately 80% SOC, it remained stable at around 51 kW for an extended period of time before declining further at approximately 90% SOC. It's obvious that charging to a high state of charge is inefficient if it's not essential to reach a destination or another charging site.

The charger reported a total energy delivery of 137 kWh to the automobile, compared to the 123 kWh recorded by the car as extra energy.

State-of-charge (SOC) vs time

During the charging session, it took 1 hour and 31 minutes to go from 0% to 100%. There was an interruption because the session time limit was 60 minutes.

• 10-80%: 42 minutes
• 20-80%: 37 minutes
• 10-90%: 56 minutes
• 20-90%: 51 minutes

Charging from 20% to 80% SOC took around 37 minutes.

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

In the critical range of 20% to 80% SOC, the average power output is 124 kW, or 68% of the peak value.

If we closely examine the data, we can see the green area—the optimal charging area—which stops at approximately 65-70 percent SOC.

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

When it comes to the 135 kWh battery capacity, the maximum C-rate* is about 1.36C.

When charging from 20% to 80% SOC, the average C-rate is 0.92C. Both figures are modest in comparison to many other electric vehicles.

*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.

We don't know the official value of net battery capacity because the manufacturer only publishes the 135 kWh figure. However, the car's display indicated that 123 kWh were added throughout the 0-100 percent SOC charging cycle.

During the previous range test, the car consumed 124 kWh of energy between 100% and practically 0% SOC. 123–124 kWh would account for 91–92% of the total of 135 kWh.

Range replenishment rate in relation to state-of-charge (SOC)

The rate at which the range is replenished is based on how much energy is used, which is based on the use case.

Use data from the EPA to figure out how quickly the range will be replenished. Keep in mind that the real-world rate is lower because of charger power reported before losses and auxiliary vehicle loads.

• Combined EPA Range

Using the EPA's combined range of 314 miles (505 kilometres) and the available battery capacity of 124 kWh, we may assume a 395 Wh/mile (245 Wh/km) energy usage.

When charging from 20% to 80% SOC, the effective average pace of range replenishment is 5.2 miles per minute (or 8.4 kilometres per minute).

• Highway range (EPA)

Using the EPA highway range of 292.9 miles (471 kilometers) and the available battery capacity of 124 kWh, we can estimate an energy consumption of 423 Wh/mile (263 Wh/km).

When charging from 20% to 80% SOC, the effective average pace of range replenishment is 4.9 miles per minute (or 7.9 kilometres per minute).

Nonetheless, to maintain a speed of roughly 6 miles per minute, we need to stop charging before reaching 60% SOC.

The ultimate fast-charging DC card

This is our ultimate charging card for the Rivian R1T. It shows how long it will take to add a certain amount of SOC points, how much energy it will take to charge, and how much more range it will go.

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 above 5%. 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). Another thing is that the charging curve might shift when charging starts at a lower/higher SOC.

Conclusions

Considering the above - mentioned results, the Rivian R1T's quick charging capabilities are "okay" - certainly not cutting-edge, especially given the battery's massive 135 kWh capacity.

There are opportunities for improvement, including increasing peak power and power above 60% SOC, as well as switching to an 800 V battery system (which is coming in the future). Charging power of about 50 kW between 80% and 90% SOC (low C-rate) seems to be too low for some adventurers who need more range.

For the time being, quick charging is a shortcoming of this fantastic automobile. Because the R1T is the market's first modern all-electric pickup truck, and the first from Rivian, we can only hope that it improves.