Hey everyone! I'm working on setting up a solar backup system and currently have a 7.2kW Tesla PV setup with a grid-tie inverter, but no Powerwall. I've looked into adding a Powerwall, but the cost per watt-hour seems unreasonable. Plus, I prefer having a system I can manage myself.
I'm considering creating an isolated off-grid system using an EG4 6000XP inverter and server rack batteries. However, I'd really like to utilize the existing Tesla panels on my roof instead of having to invest in more panels.
My current installation doesn't use microinverters, and I think I could switch the panels from the Tesla grid-tie to my off-grid inverter during a power outage to fully leverage the 7.2kW output. I would also keep about 3 or 4 panels on a different MPPT for maintenance and light loads.
Is this setup feasible? Am I overlooking anything? And if it is possible, what steps would I need to take?
1 Answer
You could actually set it up with a Sol-Ark inverter, which has both grid-tie and load ports. This way, you can benefit from grid-tie during normal operations but still power your loads when the grid is down. Just a note though, switching the solar panels between systems isn’t recommended in daylight, even with a good DC switch, since the power can spike really fast!
Switching at night could work for you! Although, I’m curious about how Tesla manages the rapid shutdown with their string inverters.