This week we received a very interesting data from our reader Rick, who was carefully recording the efficiency of its Rivian R1T in a wide spectrum of temperatures.
The Rivian R1T has an EPA Combined range of 314 miles (505 kilometers) and almost 293 miles (471 km) of EPA Highway range, but those are just single numbers for the test cycle.
Rick consistently recorded efficiency and temperature of its Rivian R1T on a frequently taken trip of 165 miles (265 km) between Minneapolis, Minnesota and Hayward, Wisconsin, which allowed him to draw several graphs in function of temperature at an average speed of 54 miles per hour (87 kilometers per hour).
Before we will get into results, let's summarize the test settings:
- Rivian R1T (owned from July 2022):
21-inch road tires
settings: always* "Conserve" drive model and "Low" ride height
* once the "Snow" mode was selected, when driving on snow covered roads
- route: 165 miles (265 km) between Minneapolis, MN and Hayward, WI
about half of the journey is on Interstate 35 (the cruise control set at 70 mph)
another half is on MN and WI state highway (speed between 55 and 60 mph)
average speed: around 54 mph (87 km/h) including slow downs through several towns on the highway portion of the trip
- data source: data comes from the trip meter on the R1T
Efficiency vs. temperature
The first thing is the efficiency of the Rivian R1T, measured at various temperatures. Rick presents the results using red points and a 2nd order curve. The shaded areas are the 95 percent confidence interval of the fitted curve. The black line for temperatures below 0 degree Fahrenheit (deg F) (-17.8 deg Celsius) - the lowest temperature data point - is an extrapolation of the data.
As we can see, the efficiency can be significantly impacted by the temperature. At 80 deg F (27 deg C) it's as high as 3.0 miles per kilowatt-hour (mi/kWh), while at 40 deg F (4 deg C) it's closer to 2.5 mi/kWh - a 17 percent drop. At a temperature of 0°F (17.8 deg C), it's below 1.75 mi/kWh so only half of the value.
Rick noted that he observed a 40 percent reduction in efficiency at zero degree F, compared to 70 deg F.
He also believes that the efficiency might be worse on shorter trips in cold temperature, compared to his 165-mile trip, because the battery has time to get up to optimum operating temperature.
Range vs. temperature
When assuming 125 kilowatt-hour (kWh) of usable battery capacity, Rick noted that the range is noticeably higher than the EPA value in a wide temperature range.
"I’ve been pleasantly surprised at how much I’ve been exceeding the EPA listed range of 314 during the summer months. On this route with my driving habits I typically see a total range of about 350 miles."
However, when there is really cold, the estimated range might decrease to 200-250 miles (322-402 km).
Efficiency vs. temperature (with and without bike rack)
The one final comparison is about the efficiency of the Rivian R1T with and without a bike rack mounted on the trailer hitch with one (or sometimes two bikes).
As we can see below, such thing also significantly reduces the range - mostly due to the worsened aerodynamics of the vehicle.
Rick concluded that overall he is very happy with the vehicle and had no issues with almost 10,000 miles on the odometer.
Hat tip to Rick!