@Siciliano:
Let's take this from the top, so it's clear.
When you're charging an EV, everything has a limit.
- The car itself has a limit: SR/SR+ has a max 208/240 VAC current of 32A.
- With a Tesla, you've got a choice: A Mobile Connector (that's the thing in the trunk) or a Wall Connector.
- Mobile Connector: Right off, these don't do more than 32A, never mind the voltage. Period. Mobile Connectors have adapters (see the link to the left to Tesla). Adapters hook up to NEMA connectors. Rule: Whatever the current rating is on the NEMA connector, one is not supposed to run more than 80% of that, steady state, by the National Electric Code.
- NEMA5-15: Standard 120 VAC wall socket adapter. The NEMA5-15 socket is rated for 15A, but, because of the NEC, the Mobile Connector/car will enforce a limit of 80% of 15A, or 12A.
- NEMA14-50: 240 VAC, 50A adapter. Maximum current is theoretically 80% of 50A, or 40A: But see the comment about the Mobile Connector not doing more than 32A (the 32A wins).
- NEMA14-30: 240vac, 30A adapter. Maximum current, enforced by the car/Mobile Connector, is 80% of that, or 24A. By now you should be getting the idea.
- Wall Connectors. These, by the name, hang on the wall and have a Tesla cable attached. There are some variations, but these babies are designed to be hard-wired into the breaker panel. A Generation 2 WC (I happen to have one) can be set to deliver 100A; there are certain old Model S's that can accept that. The general rule: One sets the rotary switches (Gen 2) or uses a web browser (Gen 3) to set the max current to 80% of the wire/breaker provided. Example: My place. I got a 60A 240 VAC breaker with some seriously hefty wire connected to a Gen 2 WC. The Gen 2 is set to 48A (80% of 60A. Again with the 80% rule.)
- Wall Connector, Take 2: Tesla has a Wall Connector with the Tesla Cable/connector on the end. There are an infinite number of other vendors of Wall Connectors, mostly with J1772 cables. Each one of those Wall Connectors has (a) an internal limit and (b) a limit set by the wire going to the breaker panel and the size of the breaker in the panel.
- Breaker Panel/Wire/Socket: If one has a NEMA14-50 on the wall, then there had better be (NEC, again) wire rated for 50A and a breaker rated at 50A and no more or less. Anything else attracts the negative attention of the electrical building inspector. If one has a NEMA14-30, then the wire can be rated for something more than 30A, say, but the breaker had better be equal to 30A to match the socket. Period.
- Load Calculation. You've had a no-kidding electrician come on down, look over your setup, put in a sub-panel, that 50A breaker, the wire for it, and presumably a socket also rated for 50A. Licensed electricians are careful to make sure that when a reasonable number of loads are active, the Main Breaker (sub panel, or the main back on the main breaker panel for the house) doesn't trip. You shouldn't have to worry about that.
The whole point: "How much current can I stuff into my car?" Answer: The Lowest Limit Wins.
Car: If it's an SR/SR+, you get 32A, max. That's all the car will do. You can do
less than that. If you got a LR or P, the car can do 48A.
Mobile Connector: The body of the thing limits to 32A.
Mobile Connector adapter: Depends upon the adapter. NEMA14-50 gets you 32A, but that's the MC itself doing that. NEMA14-30, it's 80% of 30A, or 24A. And so on. See the listing at the Tesla link, above.
Wall Connector: Gen 3 WC's can do up to 48A, but only if they're hooked to a 60A circuit. If you've got one hard-wired to a 50A circuit, then 80% of 50A=40A is all you're going to get, max. If you're using somebody else's WC, the majority of those (that are less expensive than a Gen 3 WC) do 32A max; there are pretty expensive ones that can do more than 48A, but they require a wire/breaker combo that can do 60A or more. And modern Teslas don't go higher than 48A, anyway.
Like I said: The lowest maximum wins.
Now, we've had people come by here with WC's with the incorrect settings, high or low, and set them straight. But it sounds like you're running with a Mobile Connector. Is that the case?