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The following plot shows the ratio of the actual energy consumed by my Level 1 and 2 chargers divided by the plug-in energy reported by MFM and shown on the car's trip odometers. The data is plotted for approximately each month of the year. I have a metered Level 2 Charger and use a Kill-A-Watt meter for the Level 1 Charger. So I can track of all the electricity used to charge the car. I also record all the plug-in energy recorded by the odometers in the car. In the winter time, the ratio is around 1.65. It requires a lot of energy to precondition the car--this is energy that is not recorded by the car's trip odometers. In the summer, the ratio falls to about 1.3. I don't precondition the car in the summer. The ratio in the summer is greater than one since charging the car is not 100% efficient. For the level 2 charger, efficiency is around 82%. For the level 1 charger, it is around 72%. In addition, the car uses energy to charge the 12 Volt battery occasionally, which is not recorded by the car's trip odometers. Finally, there are small vampire losses from the chargers themselves (2 - 3 watts). This data might be useful in assisting someone who is trying to estimate the actual amount of electricity consumed by the car from what the car reports on the odometer. But note that it is based on a mixture of charging with Level 1 and Level 2 chargers and Minnesota winters. You will have to compensate for any differences from these assumptions.