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Monitoring EV load in Powerwall App

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My entire house is on a 100A subpanel that my Powerwall is backing and I am about to add a new EV outlet in my garage off of the main service panel. I would like to see the load that the outlet draws in the Tesla app so I can see what my real electricity use is. Do I need a new CT? How do I configure that? The wiring for the EV outlet will probably run through the Tesla Gateway (it's a backup 2 and is also handling our solar btw) and out a knockout in the side to avoid needing to drill a new hole in the exterior wall so I could even loop the THHN wire through the existing CT if that would be easier. Would monitoring the EV load in the Tesla app scare the PW into thinking the loads are too high (obviously there's no way for the PW to discharge into the EV outlet since they are on different branches of the MSP)? That is, will trying to monitor all of my loads make things worse?
 
You either have to run the circuit to the Non-Backup lugs on the Gateway 2 or you have to reconfigure the Gateway with new CTs that are near your meter. This is not a DIY project and should be done by a Powerwall certified electrician.

I have Gateway 1 and when it was first installed in 2018, it was blind to the loads in my main panel because the Grid CTs were placed on the grid input to the Gateway Switch. The installer extended the CT wires into the main panel and moved the CTs to the main conductors between my main breaker and main panel bus. That made it so that the Grid measurement included ALL usage.
 
(obviously there's no way for the PW to discharge into the EV outlet since they are on different branches of the MSP)
That's not at all obvious. Electricity flows just fine from one branch of the MSP to another. So long as the grid is up (and you have not opened the main disconnect), locating the EV breaker in the old main panel does not affect whether the Powerwalls discharge while you charge your car. Why? Because as long as the breakers are all closed and the contactor inside the Gateway is closed then everything is connected together (although going through breakers in various places). So the load of the EV charger is seen as part of the home load by the Powerwalls. You can avoid discharging the Powerwalls by choosing a strategy that disables discharging after midnight (or whatever time is appropriate).
 
My entire house is on a 100A subpanel that my Powerwall is backing and I am about to add a new EV outlet in my garage off of the main service panel. I would like to see the load that the outlet draws in the Tesla app so I can see what my real electricity use is. Do I need a new CT? How do I configure that? The wiring for the EV outlet will probably run through the Tesla Gateway (it's a backup 2 and is also handling our solar btw) and out a knockout in the side to avoid needing to drill a new hole in the exterior wall so I could even loop the THHN wire through the existing CT if that would be easier. Would monitoring the EV load in the Tesla app scare the PW into thinking the loads are too high (obviously there's no way for the PW to discharge into the EV outlet since they are on different branches of the MSP)? That is, will trying to monitor all of my loads make things worse?
The answer is that it depends.

Where are your CT's currently located? I suspect the home consumption CT's are inside the GW2, not in the main panel. If I am correct, the car charger will not be registered by the GW2, and though power might flow there incidentally, it will not be a load that the Powerwalls can self consume and offset.

The only DIY I might recommend to someone handy is to install a 60A QO200TR to the non backup lugs inside the GW2. Before doing so, consider if you are really qualified and if not call someone who is.

This will leave the charger not backed up, but metered by the existing CT's in the GW2, and is the easiest win IMO.

If you are at all unsure, ask questions and post pictures of the inside of your MSP with the deadfront off and the GW2 with the deadfront on. Post a picture of your plans as well at least the electrical pages.
 
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It would be trivial to move the one CT I can see into the MSP: my gateway and MSP are back to back on opposite side of the wall and there is a conduit connecting them, but it looks like that CT is from/to my solar panels. Here are pics of the panels labeled. There don't appear to be any wires in the MSP besides the wires to the gateway. I had a third party installer (who were great), but they probably won't come back out for something this small, and my general electrician didn't know how to do this.
 

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You do not want to move that CT. Either get an additional CT and reprogram the GW2 with the additional load, and add the car charger breaker in your MSP You should ask your installer for this CT.

If you do what I recommended above with the non-backup lugs the only down side is that both your car charger and your house loads will be sharing the same 100A subfeed. The charger alone will occupy a lot of that and may trip the 100A breaker. It is probably slightly better depending on your loads to land the car charger with new CT's in the distribution bus of the MSP.
 
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