Normal ev chargers are most efficient at 240v (low 90s) and very low at 120v (low 80s). Add to that the battery management fixed load of a few hundred watts, this leaves us with 900w usable on a tesla car.
The solution is simple, use 2 single voltage chargers made for peak efficiency at 115vac, this gets us to 96% efficiency easy.
Then for 240v charging we just stack the charger inputs. The biggest win is havinf 2 120v inputs, this lets us charge at 3kw or 30 mph!! On a model 3 to get 30 mph requires a 40 amp 240v dryer plug. Over night you would get 360 miles making road trips charger free because you can just charge at your airbnb. This is crazy valuable for many parts of the world where ev chargers do not exist.