There are many discussions on what accessories to select to keep power consumption to a minimum (and boost range). LED, heat pump, chargers… Sorry to disappoint all speed lovers, but keep your right foot light on the pedal if you want range.
To understand the relationship between speed and power consumption I drove the same highway back and forth a few times in different speeds. The car was preheated and had gone 20 km to reach the test stretch so the conditions were about the same. The test was done with all speeds in both directions so wind and hills should be about the same. The car was put on cruise control in all tests.
In 80 km/h (50 mph) the average power consumption was 14.8 kWh / 100 km on the test stretch. When the speed was increased to 100 km/h (62 mph) the power consumption increased to 18.5 kWh / 100 km. Finally a speed of 120 km/h (74 mph) was tested under the same conditions and the power consumption then increased to 22.7 kWh / 100 km. While power consumption of course is influenced by conditions like temperature, road conditions, etc the take away from this experience is the difference in power consumption given different speeds. While not entirely scientific because of few data points the conclusion from my little test was that the power consumption is 25% higher in 100 km/h compared to 80 km/h. In 120 km/h it is 53% higher!
To put this in a way that is easier to understand. Let’s assume there is power left in the car to take you 100 km if you cruise at 120 km/h. If the speed is reduced to 100 km/h the range is increased with 23 km and if it is further reduced to 80 km/h the range will be 153 km.
It should be underlined that range has never been an issue in my daily commuting and I find range anxiety grossly exaggerated in media. But if you have to travel far and charge stations are scarce, then these statistics are good to keep in mind.