Off topic, so my last post here until there is more info on the battery...
It's surprisingly difficult to find one quick definitive link (I might have missed it). But you can look around at various articles, and it's mentioned in numerous places. If in doubt, you can go to the EPA document lookup, which has ALL the information on the test done on the car (not available for this one - yet). And then calculate the numbers yourself. You'll find that if you calculate the numbers that they align with the MPGe numbers on the Monroney, as long as you include the charging losses.
For example, Model 3 SR has a range of 263 miles and took 62.2kWh to charge up:
https://iaspub.epa.gov/otaqpub/display_file.jsp?docid=51461&flag=1
That's an MPGe of 263mi/(62.6kWh/33.705kWh/Ge) = 142MPGe
That is exactly what it is listed as:
Fuel economy of the . 1984 to present Buyer's Guide to Fuel Efficient Cars and Trucks. Estimates of gas mileage, greenhouse gas emissions, safety ratings, and air pollution ratings for new and used cars and trucks.
www.fueleconomy.gov
Yes, the charging losses depend on amperage, etc. They typically seem to assume the maximum charge rate for the vehicle since that is where efficiency is best. Obviously they're totally different for Supercharging (though they are still there on the Supercharger side).
It makes sense to include them in the rating, because the losses are large, and otherwise there would be no incentive for manufacturers to keep them as low as possible.
Anyway, I'll sit on the sidelines now.