Dala, thanks for posting this. I can 100% appreciate the interest in the live data as I do something similar with my solar pool automation. It's pretty amazing once you realise how much energy is actually present in a square metre of solar exposure! I calculate live BTU measurements from my system (the system generates up to 100K BTU) based on actual flow and live input/output data as well as post a few data points from my SmarthThings hub, via hundredgraphs. I look forward to updates on your system as to how many kWh you are pumping out

Is the system based on microinverters, or is this a string system?
Here is live data from my pool automation system. You need to click the "All" button on the page to view the data...
https://www.hundredgraphs.com/public/denwood
So what are you planning to use for the powerwall? I'd take a wild guess and say LEAF battery..ha.