I installed this medium size Solar System in December 2011. Due to the continual Black-outs as well as
Load-Shedding because of  the incompetence of everybody involved in the provision of electricity I decided
to become independent from the Grid. The system is producing 50% more KWh than we are using on average. We did an upgrade in late March where we added 5 more 250 Watt panels and reconfigured
all of the panels as 3x7.
(Three 250Watt panels in series and 7 of these in parallel.) This modification proved most beneficial
as the MPPT (Multi point Power Tracker) now has the required headroom to adjust the maximum power point (that is the point on the solar panel operating characteristic) where the panels produce the highest
power for the prevailing weather conditions.

Since the upgrade (24 March 2012) we produced approx. 900 kWh of solar energy. 27kWh per day average. Usage was approx. 700 kWh. So despite a few days with relatively low insolation (that is the term used to describe how  much sunlight is reaching the earths surface) we had an excess of 200kWh which was returned to the grid.
Only yesterday we had a cold and totally overcast day and still we managed 9kWh, 40% of the demand.

The systems performance can be monitored either On-line via a G3 link or connecting one of our Laptops
to the inverter and having access to all data as well as being able to set all of the operating modes.
All relevant performance data is stored on a memory card and can be accessed and plotted with the
software package provided. When using the SCADA functionality one can monitor the entire system
with all its connected sources and loads. Very much like a real power station.
I will post some graphs in the near future. Of course this does not come cheap. But my Porsche deserves
a warm garage.