80A is the maximum that L2 will provide. A lot of them sit at around 30A however.

So, Ron, for future-proofing, what size wire would you use - especially if you might want chargers for two cars? 160 Amps requires awfully heavy wire? I'm having a carport built which will be about 25 feet away from the house and I guess the wires must be buried 18", coming out through the foundation of my house right next to my breaker boxes (the power from the POCO comes into the back of the boxes at about that depth - two 200A lines).

160 might be overkill. Tesla is currently recommending 60A circuits for their home chargers. Note that if you're going to have multiple circuits in the carport, you will need to put in a grounding system (rods) there.

I hadn't thought about two separate circuits, but I suppose that's a good idea, especially if I want a lighting/utility circuit also. Should I run two (or more) cables to separate boxes and connect all the grounds together and to the grounding rod(s)? Or should I put in a sub-panel? Remember, this is in a carport, not a garage, so everything must be weatherproof.

If you are going to have multiple circuits in the carport, you need a sub panel. Only a single circuit (or multi-wire circuit) can feed a detached building without a sub panel.

That's assuming a carport is considered a 'building'. I personally would think it is, but maybe it's arguable.

Greg is right (and since L2 chargers are 240, you won't be using MWBC to feed them).

The code is pretty clear on structures that require grounding. If the carport is detached from the main house it needs grounding for multiple circuits even if it is nothing other than four poles and a piece of canvas.

So, it sounds like I have to run #1 wire to provide two 60A 240 volt circuits and one 20A 120 volt utility circuit to a sub panel. Are weatherproof sub panels available? I assume the utility circuit must be GFCI protected, probably just a GFCI receptacle in my case. The ampacity chart I used specified THWN-2, THHN, or XHHW-2 wire. Should I use steel or plastic conduit?