I have searched TMC for charging efficiency threads but haven't found a simple way to determine how much AC power is drawn per kWh put into the battery and none of the posts used a 30A 240V source. I am using a 30A dryer circuit and can see on the charging screen that I am charging at 234V, 24A. At my main panel the usage will be greater, since the UMC is seeing only what is available to it at the 10-30 outlet, after line losses. When not in use, the voltage on the circuit reads 240, so I presume that usage at the meter would be measured at 240V, with the difference being from line losses. If I set charging units to percent, I can record beginning and ending SOC percentages to calculate kWh received. From time of charging at 24A 234V and converting to 240V as received at the meter, I can calculate kWh AC consumed by the charger. Then it is trivial to calculate charging efficiency. Yes? I should then be able to calculate wall-to-wheel cost. Am I missing something significant? Is there a better way?