new system designed by myself

Re: new system designed by myself

I believe SMA has a string calculator... But I will use the Xantrex one for now as it is one that I know and understand its output...

First, really need to know the exact panel model number or Vmp, Voc, Imp, etc... Since you are planning on 10 in series--any errors can get multiplied by 10x.

Using the Xantrex Calculator--And Sharp NT-175U1 panels, Set your min/max temperatures for your region (say -5 to 35 C) (and you can pick any Xantrex inverter around the wattage of the SMA--we just want the numbers):

Max Power Voltage - Vmp 35.4 Vdc
Open Circuit Voltage - Voc 44.4 Vdc
Voltage Temp Coeff - Vtoc -0.144 V/°C
STC Rating - Pmp 175 Wstcdc
Max Power Current - Imp 4.95 Adc
PTC Rating 154.2 Wptc

Looking at the Max/Min voltage chart (for -5 to 35C):

[FONT=Fixedsys]
Max Voc Min Temp    Min Vmpat Max Temp(Vdc)
==========================================
8 Modules    389.76    231.36
9 Modules    438.48    260.28
[B]10 Modules    487.2    289.2[/B]
11 Modules    535.92    318.12
12 Modules    584.64    347.04[/FONT]

The Voc (open circuit, -5C) voltage for 10 panels is 487 volts--looks good.
The Vmp (maximum power 35C ambient) for 10 panels is 289 volts--looks good.

So, I don't see any issue in your sizing/string setup.

Sounds like you are roof line limited--So, you don't really have to question if you get more before noon or after noon sun (optimum collector placement) and you did not say what kind of billing you have (flat rate or Time of Use--Flat rate, setup for maximum power collection--Time of Use typically charges more for afternoon power--so optimum is to setup panels for more afternoon collection).

Mount panels at around 5-6 inches off of the roof (or more) for better air circulation (cool panels generate more voltage, P=I*V so higher V means higher P-power).

Most panels (at least in the US) come with MC type connectors--you should get a tool/parts to mate to them, or get Male/Female pig-tales you can cut in half (plug to panel, hardware to your system wiring).

Note that PTC and CEC (from the Xantrex support page) are ratings used by California (and probably others) to rate GT systems for their "more realistic" average output (rebate calculations) vs the "marketing" STC ratings that panel mfg. use.

-Bill

PS: I am sure you are aware of shading... Difficult to tell from picture, but you may have significant shading in the winter (sun low in sky)...

Re: new system designed by myself

Regarding your panels... Make sure they are rated for high voltage (at least in the US, that is usually 600 VAC minimum for the electric code) and have appropriate approval (UL, CSA, ETL, GS, TUV, BSA, or whatever is required for your area).

There are some panels that are designed for battery systems and not rated to put 10+ modules into series... Need the exact model number and spec. sheet (or look in Inspector's handbook) to ensure appropriate approvals (I don't think you have a problem/issue--but is a requirement for the panels to meet).

-Bill