Comparing Energy Consumption Measurements

The 2023 Prius Prime offers two useful values related to energy usage - "Power Consumption" [Rate] in miles per kilowatt-hour, and "Charge Remaining" in percent of EV mode battery capacity.

The amount of power consumed can be estimated using the formulas:
- Power_Consumed =~= Delta_Charge_Remaining * 10.6 kWh
- Power_Consumed =~= Miles_Driven / Power_Consumption_Rate

The amount of power drawn from the wall (with the stock EVSE) to replace the Power_Consumed can be measured using an inexpensive watt-meter (around 1% percent accuracy with 4 digit precision).

I have been tracking both of the estimates of Power_Consumed compared with the Wall_Power_Drawn and found:
- Power_Consumption estimate by Delta_Charge_Remaining to vary +/- 6%
- Power_Consumption estimate by Power_Consumption_Rate to vary only +/- 2%

Thinking about how each quantity is derived suggests these results are reasonable. Current and Voltage can be measured to any desired accuracy with respect to time, but the power remaining in a battery can only be estimated based on a voltage curve under load which varies with the load and battery age.

(The Charge_Remaining value is automatically maintained, where the Power_Consumption_Rate requires a reset at the start of the day, and cannot be viewed if Charge_Remaining reaches ----% making it less convenient than the Charge_Remaining measure.)