I am looking at adding solar+2 powerwalls. One question I have is, what happens if you exceed the output of the powerwall. I don't want to turn on a light switch that causes a brown out, because I exceed the max. output of the walls. Is there any mechansim built in to the powerwall, or is it on the user to not overdraw the system? Also, is wifi acceptable, or does the system really need a wired ethernet connection? Thanks.