I have one of the 1938241-00-A devices from Amazon. Actually I have two, one for tinkering and one that will get installed. A little glitch has come up. The CTs don't fit around the input bus bars on my year old SquareD SC3042M200PF meter panel. I'm assuming CTs will not work correctly unless the split side fully closes. I'm pondering if PG&E would let the CTs be connected around the service entrance wires upstream from the meter, in the utility sealed section of the panel. I think it's likely they don't exceed the 0.75" limit, and the meter panel is customer owned, but assume the wires are utility owned and maintained. I'm not sure who to contact at PG&E support for a question like this. I'm super happy to see Tesla Wall Charger support dynamic load management, and perhaps they will read this and for future customers use CTs with a larger hole. The CTs for my Enphase solar fit just fine, I think they have a 1" square hole.
The device talks RS-485 modbus RTU at 115200,8,1. I unfortunately don't know what the modbus register map is but am putting together some stuff to make good traces of the communication to the Universal Wall Connector. I looked at it on a scope and the Wall connector polls every second and the Neurio responds. The serial decode said the RTU request was read 10 holding registers at address 0x88 and the sensor responds back with 20 bytes of payload, which I don't know the meaning of yet. There may also be some startup handshaking, like asking what model of load controller it is. When I get good tracing working I'll try to vary the power parameters and see how the returned data changes. I see if the Wall Connector looses connectivity to the modbus sensor it retards back to 6A charging. I don't yet know what it does when the current limit is reached.
I don't have things installed yet, and am currently collecting parts and verifying everything fits and works. I haven't decided for sure if I will do the actual install or get an electrical contractor. My brain says DIY, my not so young back says hire an electrical contractor. Either way, I do want to be sure all the parts will work out. I'm guessing a contractor would not have figured out the CT doesn't fit until installation was started, so discovering this beforehand was fortunate. I don't know of a different load manager for a Tesla Wall Connector.
In an ideal world, what I probably want is a little gadget that talks ZigBee to my PG&E electric meter (I have a Rainforest Automation Eagle that does this now for years) and constantly reports power consumption to some local energy manager. Ideally, the Wall Charger could pull the power limit over WiFi. A little less ideal, a little box, like maybe a modbus to wifi gateway ($38 on Amazon) could bridge communication to the local energy manager, and respond to the modbus requests from the Wall Connector, avoiding the need for another CT sensor. My meter panel already has CT coils to my Enphase solar controller, so it's a bit silly to need a second set of CTs for the EV charger. The first CT's are silly because my meter already talks ZigBee reporting instantaneous power consumption (well delayed a second or two). I'm probably just going have a straight install of the Wall Connector and load manager, but figure while it's not yet connected I should record what it does for some future home automation company or DIY. Tesla could just make this really simple and perhaps could even make load management of the mobile connector plugged into a NEMA 14-50 outlet.