The deeper I get into investigating rooftop solar, the more confusing some of it seems to get. For this thread, I want to focus on how to ensure I can integrate a load balancing battery system like the PowerWall into a rooftop solar installation. The solar installer I am currently talking to can install Sonnen battery systems and claims they can retrofit battery systems at a later date (desirable to me to spread out the cost a little over time), but claims and realities do not always coincide. What do I need to do to ensure the system I have installed can be used in combination with a load balancing battery system? Will that differ depending on whose battery I use (PowerWall vs Sonnen)? And who is the right person to even ask? If I want a PowerWall, do I need to ask Tesla about this? Thanks for any thoughts.