Unless it has been removed for gen2, there is a PID available over OBD - last charge Wh. It appears to be total energy that has gone through the charger during last charge event. Includes charging losses - reads about 12k for a ~10.5kWh gen1 charge. Note it resets upon full charge and initiating a new charge - so doing a full charge overnight and a remote start in the morning may erase it and only count the remote start energy.