I am fortunate enough to be able to run a small business so I get the equipment at dealer cost, but basically it cost about R2750 per invertor, each can do 240W-260W I have 250w panels attached, so for 2500w or 2500KVA it will be about R27500.
Since my last post I installed a further 4 panels so my array is now 2KW, and I have to say that I must at least be getting > 20% more production than a single string inverter. With the I-Manager "R3500" you can see historically and realtime, that often during the day as cloud's, tree's and morning's and evening as shadows effect the panels, 6/8 of the panels still producing 200W+ and the other 2 100W-120W and as the shadow shifts you can see it move on the array.
I am very impressed, the only thing is my roof is at about 18deg and we have just come out of winter where the inclination should have been like 56deg. So not good for winter but, mid to end spring they'll be perfect, for or summer months 2deg is optimum.
The installation was a real breeze and I did it all my self .With the i-enegery inverters you can connect a maximum of 17 on a bus, I say bus because each micro inverter is connected the next and so on and so forth, but the string acts as a busbar, so if one would fail the rest would still operate without hindrance. Then from the roof I used 2.5mm surfix under the roof tile and directly into a 2 pole 20A circuit breaker in my distribution board, from this breaker into the out of the mains 63A breaker. As simple as that and it complies with all safety regulations. This alone should convince anyone that micro-inverter is the way to go.
What I have also done is gotten hold of monitoring equipment from
OpenenergyMonitor, I got the emonTX, emonGLCD and the Raspberry PI as the base station and boy am I impressed, together all of these monitor my Solar Gen and House Usage, Grid Import/Export, Power Factor, Voltage and basically anything else you want to add and posts everything to the locate DB on the Raspberry PI which can post to a web based system online "emoncms.org" and both are very configurable and have web interfaces
Demo Dashboard, I have temperature controllers no their way and with these I'll be installing 2 on the hot water geyser and 2 on my solar water collector, I can them using the same emonTX monitor top and bottom temperatures of the geyser and solar collectors and with a bit of sketch code control the 12V solar pump to ensure at no point am I feeding cooler water into the geyser than what's already in the geyser, it will also give me an idea of the temperature through out the system. There are also guys doing load diversion with the same systems.
Anyways that's my 2 cents worth.