At those capacities and charging times there's no chance of it not being some medium voltage (4160v or higher) equipment. Even a 480v 3ph low voltage building power system wouldn't be realistic because a single charger would be more than double the service size as the entire remainder of the gas station. However it would be done this would need a massive upgrade in electrical that isn't going to be available at your neighborhoo station. Also raises some safety and logistics concerns, you can't trust the average person with that degree of potential hazard.