I bought a 840 watt system the other day. As I began to plan the load senario for my green circut, I quickly came to the conclusion I need additional power. I intend to install the system as purchased, but it won't be as valuable to me as it could be. So once I get it installed, and figured out, I'm sure I will have to upgrade it. I was looking for whats availalbe and how much it's going to cost.