13.2kW solar + Tesla Powerwall 3.

A west-facing roof, a growing power bill, and an EV on the way. We designed a 13.2kW system with a Powerwall 3 and got the household to 92% self-sufficient.

The family had been quoted three times and each quote looked different. One had the panels facing the wrong way for afternoon sun, one ignored the battery, one was cheap but used a brand we wouldn't put on our own roofs. We took an hour on the first visit to explain why.

Final design: 33 × 400W Longi Hi-MO panels, Fronius Symo 10kW inverter, Tesla Powerwall 3 with integrated backup. Split string across east and west roofs to widen the generation window — peak output in both the morning school-run hour and the afternoon EV-charge window.

Install ran two days. Day one: mounts, rails, panels, DC-side wiring. Day two: inverter, battery, switchboard integration, commissioning. Ausgrid approval was pre-lodged so export limits were live from day one.

We wired the Powerwall for whole-home backup — during the February outage they were the only house on the street with lights on. The monitoring app shows generation, consumption, and battery state in real-time, and we sent the family a one-page cheat-sheet so they actually read it.

Twelve-month follow-up: self-sufficiency sitting at 92%, bill down from $780/quarter to a $40 credit. Payback tracking at 6.2 years, not the 9 the other quotes assumed.