Want to add separate DIY system to existing Tesla solar and Powerwalls. Where to connect?

[dailo]

Why would you use an additional Neurio when there are at least 3 empty CT channels in the Gateway 2 pictured in this thread? The only reason I can think of is that the distance exceeds normal CT wiring, which probably doesn't apply to this case. The reason the CTs are empty in this case is that the solar production is reported digitally by the Tesla inverter. Adding 3rd party solar would require CT metering to be logically added in the Gateway to the solar quantity reported by the Tesla inverter.

I had asked the same question but the tech said it was just easier. They were able to install the neurio on the main panel instead of having to run the wires through the conduit from the PW+.

 

[miimura]

If you had a backup switch instead of GW2.

Ok, I went back and re-read this thread and I see where I went off track.

@wwhitney was pondering how to properly do PV Production Metering with a utility provided meter and a Powerwall+ and you (@Vines) answered regarding Tesla CT metering. Then @dailo interjected with Backup Switch +Neurio for Tesla solar measurement.

In the big picture, getting the solar measurement into the Tesla system so Powerwalls behave as expected has a couple solutions and is relatively easy. How to add solar when your utility requires production metering raises the complexity a bit.

 

[ascottallison]

Thank you everyone for your help on this matter! I had a closer look at the inverter and have discovered there's a Neurio on the right hand side, with a single CT connected (1 of 4 ports). The Generac branded CT is hiding on the left hand side.

Here's the CT:

My strings are connected in the top right pattern shown here "4 combined strings":

According to this sketch Tesla gave me this is how the strings are wired:

• String 1 has 2 strings of 5 panels in parallel
• String 2 has 2 strings of 7 panels in parallel

But that seems to contradict the label which says "Combined strings must have equal quantity of panels". Or am I misinterpreting this?

Panels are Q-Cell 340W (each have a max of 40V) - so the string of 7 has a voltage of 7 * 40V = 280V

Blue string faces south and the red string faces east. The West roof has pool solar on it, except the NW corner which Tesla were originally going to put 4 panels on but then changed their mind and moved them to the south roof on the day of install.