It would be interesting if the charger was lobotomized internally. If only one branch circuit is available, it charges the car based on 15/20 amps available. If two, then it utilizes both. If three, all three. A bunch of small chargers all paralleled to make DC for charging purposes. Gets you a scalable solution for when you don't have a hard level-2 source (220V, >30A) installed.
My carpet cleaner use to have a machine that worked like this. He parked it in my hall and then ran extension cords to three rooms. Two ran heaters. One ran the motors and pumps. His machine used three circuits, independently.
Interesting, I didn't know US residential's 2 phases are actually 180 degrees apart instead of 120 degrees. I would imagine the transformer in the neighborhood just send 2 phases to each house instead.
Still 208 vs 240V apart is still charging at the same 12A constant current, so it is 15% faster using 240V. I think the biggest pain in the butt is to find the other "phase" nearby so you don't have to run long wires from one end of the house to another, or one floor to another.
Because in the US, low density neighborhoods are typically fed by a single high voltage "phase." You see transmission lines are always in threes, but within the neighborhood, only one runs down the street.
So then that one line has a bunch stepdown transformers to serve the houses. Each stepdown transformer is center tapped to provide two legs, 180 out. Same phase, opposite polarity. Residential split phase is not 2/3 of three phase. It's actually 1/3 of three phase.
But when there's a church, school, or store...they likely ran three lines of service to it. In that case you might see three transformers on a pole or a big three phase unit on the ground.
That's why the utility shakes their head if you're in a residential area and want three phase for your shop air compressor, 5hp table saw, big planer/jointer, old bridgeport, etc. They need all three phases in order to supply three phase power. The infrastructure doesn't support it. If they have two phases nearby and you don't need a bunch of power they can compromise and get it with two out of three legs.
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That happens at times you lose a hot leg from the utility side and only half your house has power. That was nice of the utility company did it supply power just to your residence or the neighborhood?
Worse would be if a squirrel has chewed through the aluminum neutral. Two hots and a floating neutral for all the branch circuits...
In residential 240/120 split phase, the two legs are derived at the service transformer from a single supply leg. They're not really separate "phases." Same "phase" but opposite polarity.
