have a look at this guy using a cheap grid tie inverter, i think it is much better option at a lower initial cost and you can always add to it as you go even adding batteries.

in this video series he explains it in detail
https://www.youtube.com/watch?v=o5rI0smOivk&list=PL58a2JuD4OTsfLpQtZRIlEfDxijRzK-Iy