The Sunnyboy is a single MPPT (maximum power point tracker) inverter only. There is normally a breaker in both the (+) and the (-) lead, which is why you have two breakers.
Your CEEG panels are monocrystalline, rated at 44.4 volts open circuit and 5.29 amperes short circuit, so six panels in one string adds up to 266 volts maximum.
The SB1700 inverter has a maximum input voltage of 400 volts and maximum current of 12.6 amperes, so there is scope to add panels. The start-up voltage of the SB1700 is 180 volts, so you need 180/44.4 rounded up = a minimum of 5 of your panels in a string for it to run. The inverter has two string inputs, but these actually connect “in parallel” inside the inverter and share a single MPPT, so it is ideally only a single string inverter.
I have the same inverter and I added an extra panel to my originally 8 x 190 watt panel array to make 9 panels in one string. I was lucky enough to buy a matching panel through Gumtree, but I looked for about a year before I found one.
Matching panels exactly probably isn't quite as important as most people think. What you need is to match the current rating and cell type for a single string, or string voltage if setting up a second parallel string with this inverter’s second inputs. Bear in mind that used panels will not match new panels anyway, due to aging of the panels.
Over on the Whirlpool forum, there is a lot of experience in paralleling strings of different orientations, say one set east and one set west, on the one inverter with a single MPPT. Note to do this they must be the same number of the same voltage panels in each string. You could run two strings of 5 panels, one sting on your north east side and one on the north west side. The slight de-rating by not having a dual MPPT tracker inverter can be offset by a longer period of generation due to the spread orientation.
You could even “over-clock” your inverter and run two strings of six panels totalling 2040 watts, a technique which is also commonly reported in the Whirlpool Green Tech forum. What happens then is that under perfect conditions when the solar panels are at peak performance, the inverter will power limit to stay within its 1850 watt input power rating. This is “safe” because two strings of six panels is still within the voltage and current ratings of the inverter. However check with your supplier first.
Posted Tuesday 26 Mar 2013 @ 4:16:38 am from IP
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