Join Date: Jan 2019
Location: San Francisco, CA
I did a similar analysis comparing Journey's miles/kWh to my calculations using the I-Pace's onboard SOC reading. I only did it for only one charge cycle. For 6 trips (power on-off cycle) totaling 112 miles in distance, with trips ranging from 61 miles to less than 3 miles, Journey's weighted average energy consumption (weighted by miles traveled per trip) was 2.88 m/kWh. My calculation, based on the I-Pace's SOC % reading and assuming a battery capacity of 84.7 kWh, was 2.49 m/kWh. So, Journey overstates efficiency by about 15%.
If you prefer kwh/100mi, Journey: 2.88 m/kWh = 34.68 kWh/100 m and My calculations: 2.49 m/kWh = 40.08 kWh/100 m.
Unfortunately, I can't use sciencegeek's suggestion of comparing the results to the amount of kWh supplied from my ChargePoint EVSE, because I rarely charge to 100%. So, I can't determine how much charge was consumed per charge cycle, only how much was supplied.
I-Pace FE, Corris Gray, 20" rims