I manage a six-unit building in southern Maine, nothing fancy, three floors, shared parking lot behind the building. Two years ago one of the tenants asked about installing a charger for her own use and we ended up putting in a single Tesla Wall Connector on the building's electrical service, wired to a subpanel we already had room on. That's worked fine, she's the only one using it.
Now a second tenant just leased a Model Y and asked if we could add a spot for him too. My first instinct was to just call the same electrician back and put in a second, completely separate circuit, but when I mentioned it he brought up Power Sharing instead, apparently you can run multiple Wall Connectors off the same circuit and they talk to each other and split the available power between whoever's actually plugged in.
That sounds great in theory but I don't fully understand the mechanics of it. Is it a fixed 50/50 split whenever two are plugged in, or does it actually change in real time depending on who's charging? What happens if a third tenant eventually wants one, does it just handle that automatically since it caps out at 6 units, or does each additional unit need its own conversation with the electrician about capacity? And does this actually save us from having to upgrade the panel, or am I just delaying that conversation?
I'd rather understand this properly before I sign off on it for the building, since I'm the one who has to explain it to tenants (and to my boss) if it doesn't work the way it's supposed to.
