Off-Grid - thanks for such detailed information. No, I was not thinking of oversizing when planning the installation. It was not even thought of, mentioned, in the margins at all. Dealers don't seem to be in the loop for that. All focus went on what type of panels, and what type of inverter and getting approval before cut off date. While it seemed that Sunpower panels were reported to be the most efficient of all, it was going to cost me an EXTRA $120 per panel to install on tiled roof (they halved that charge in a follow-up quote). Therefore the less panels the better, so 12 x 318watts fitted the bill rather than 20 x 190 watts or whatever. Also, do not have roofs facing east and west, so did not have different orientation choices. Although up here North seems to be considered optimal.
It seems to me, however, that having part of an array on east and west is 'self-clipping' in itself. Eastern orientation stops producing early, and Western orientation starts producing late. So compared to the clipping of an oversized array, it probably works out even in the end.
As I have 12 panels in one row across the roof (2 strings of 6), with the cabling from the far end 6 going under the panels of the 6 closest to the inverter, switching them to 2 x 5 and 1 x 6 may be costly. Perhaps the far 6 stay as they are, and 1 from the closest 6 becomes 1 + 4 new ones (in a second row) will do the trick. I hope to nail the dealer/installer tomorrow about it. They are very busy with new installs. Whether I go ahead or not will depend on all up cost.
The SB3800 specs read:
No. of MPP trackers / strings per MPP tracker = 1 / 3
TonyT - I searched pvoutput.org specifically for SA systems and did not find any that maxed out in my small search. Strange that Perth and Vic have systems that max out and not SA.
Greg - thanks for the heads up on Sunny Design. I did not think it was for free.
Thanks everyone for your input - all appreciated.
Posted Thursday 7 Mar 2013 @ 2:32:10 am from IP
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