Well, that's the thing. The EVSC does report a 16amp limit as it's designed for a NEMA 6-20 outlet and hitherto (3 months) the car was compliant.
What is the EVSE advertising? Dialing back the number of amps on the car should only be done to extend charging time (so that charging completes when you want it to instead of earlier). It should never, ever create a safety issue if the car is actually drawing the number of amps the EVSE advertises (which it can, any time, due to software bugs, etc.).
What is happening is that the car is consistently drawing more current than the set limit via the Tesla app or via the car's charge menu. I get that the car shouldn't exceed the EVSE's signalled output, but it is doing that as well.
Yes the car is not complying with the EVSE's limit (when it did for 3 months).
Nope, there is no scenario where you're ever sharing a circuit and the two EVSEs are collectively advertising more current than the circuit is capable of supplying. That's against code and is a good scenario to start a fire. The EVSEs either need to communicate and reduce their collective advertised current, or you need to install a separate circuit.
How are you verifying how much current the vehicle is pulling? I hope you're using a current meter, not the reading given by the vehicle (which could be a software bug).
Just for the record I'm using a dedicated 20amp 240v circuit and NEMA 6-20 outlet. However, every Tesla prior to April last year came with an Tesla mobile charger and a 120V NEMA 5-15 adapter. Obviously, there are occasions when the charger will be plugged into a 120v outlet on a shared circuit and the car's current limit can be reduced via the charging menu or Tesla app. When you set the current limit via the charging menu the car should comply.
The EVSE reports the amps and volts that the car is requesting and receiving and it shows one amp higher than the car's amp limit as set in the charger menu, as does the car itself on the main display.
Yes, it should. The car should also not do a lot of things that it ends up doing because of Tesla's software bugs too (i.e. the charge port shouldn't slam shut immediately after you remove the connector, the playlist should come up when you connect a phone with Bluetooth, the trunk shouldn't have trouble opening and closing, etc.), but a software bug should never cause a fire because the current limits should be enforced by the hardware.
Did this just start happening? If so, I'd submit a bug report to Tesla.
Yeah, could be that the EVSE isn't reporting the exact amount of current being used. Wouldn't be surprised if its reading isn't as accurate as a current meter (the type you put around a wire and detects the magnetic fields).
I’m just gonna go out on a limb here and offer up that I’d suspect problems with the cheap Chinese EVSE before the car.
Although:
Could the EVSE be advertising the wrong circuit capacity? OP should try a different EVSE and see what happens. Additionally, get a clamp current meter and use it to measure the actual amount of current in the circuit (may have to open up the panel to get to the wiring easily).
I ordered a Tesla NEMA 6-20 adapter for my Tesla Mobile charger and I'll compare them, when it arrives.
