Looking at the network activity of the Tesla Powerwall. Also a bit of an insight as to how the fault finding and resolution process of that company operates.

curl -k -O -c cookies.txt -X POST https://powerwall/api/login/Basic -H "Content-Type: application/json" -d "{\"username\": \"customer\",\"email\": \"[email protected]\",\"password\": \"PASSWORD\"}"

curl -k -O -b cookies.txt https://powerwall/api/meters/aggregates