I'm planning on making a grid tied solar install for my house in Cape Town.
Due to costs, I can't really install a small system, as shipping / clearance is a huge cost over the entire system.
With that in mind, I'm planning on a 30 panel / 300W setup using Poly panels. Mono panels aren't really worth the extra 15% in cost over poly imho, but feel free to change my mind with facts
Currently panel cost in China for low qty (eg a palette of 20 panels) before shipping is:
700RMB / panel for 300W 37v @ 8A (Poly) 1957*992*50mm
900RMB / panel for 300W 37v @ 8A (Mono) 1957*992*50mm
My plan is 30 panels in 2 x 15 string's so voltages will be roughly 570DC / 8A
Will wire panels -> DC isolator switch -> 3 phase inverter -> grid for a grid-tie solution.
This is what the current grid-tie solutions appear to be doing, although it is illegal without the relevant permits in place. I'd like to be legal, but Cape Town doesn't want to support solar producers, so I may end up just dropping off grid completely with a battery setup, and Eskom for emergencies.
The house is currently 3 phase, so I plan to stick with that. I do realise that I could do a 1 phase inverter, and put the output on 1 phase, but the cost for 3 phase isn't that much more in the 10KV input range, so I think better to stick to the same wiring where possible.
Inverter will be a grid tied inverter 10KV 3 Phase (as my house is 3 phase).
Startup voltage is 350V, max voltage is 1000V, so well within limits.
Open voltage on panels is similar to load, so thats ok also.
Our current usage is about 15,000W daily, a 9KW system should be able to get us about 25KW in winter and 40-45KW in summer in theory, so we'll have plenty of excess.
We do have an analogue meter, so that can run backwards if we do run that into the grid.
I realise that I'll need to make sure that the excess isn't too excess, as otherwise Eskom will be interested why the bill is in minus points, but I'm not so worried.
Phase one of install will be panels + inverter for grid tie.
I'd love to go completely off grid, but funding doesn't really cut it just yet.
Any comments from the peanut gallery as to what I plan so far?
Phase two will probably be the addition of a Sunny Island 6A + Automatic switchbox + battery charger + batteries.
With that I can add off grid capabilities.
I have a blog post here -
http://www.computersolutions.cn/blog/2013/05/going-solar/ with details on inverter and panels if people want more info.
Oh, and thanks to M.J for the forum and youtube videos.