I posted this in another thread but it is relevant here too:
Quite amazing that the EV6 does not come with any charging cable at all. We bitched about this enough that the dealer agreed to pay for a cable. We ordered one from Amazon for $160:
Schumacher SC1455 Portable EV Charger– Level 1 and Level 2, 16A, 240V
One thing that attracted me is that it has a 23-ft cord, so one can park quite some distance from a receptacle. Not an issue at home but it was very helpful when we stayed at an AirB&B for 4 days.
That said, the answer to your question depends on your driving pattern. Our daily use varies from 0 to 50 miles with occasional road trips where we use public charging stations. We will rely on an existing 110V receptacle in the garage for all home charging. This will easily put 50 miles into the battery overnight. We have the top charge limit set at 90% for daily use, then bump it up to 100% the night before leaving on a trip. If we should happen to get caught short, there is an Electrify America 350kW station three miles away.
If you drive >50 mi/day, then a 220V receptacle is called for. A basic 20-amp circuit that can be wired with 12-3 Romax will get you about 130 miles overnight. A NEMA 6-50 adapter, which uses an electric-range receptacle, would give you a nearly full charge overnight. For this you need a stronger charger than our Schumacher.