I often get questions regarding the size of the system one should have to power equipment at home. It does depend on the type of load one uses and the duration of use.
Typically you would want to use lighting loads, in that case you will need a small system, maybe just one module. There are quite a few freebies to plan such systems. The best one
http://www.sma.de/en/products/plant-planning/sunny-design.html
In case you are looking for just numbers i found this product catalog
Mission Shunya 
http://www.advancepower.net/advcalc.htm