I have an off-grid cottage that currently has two damaged panels I got a few years ago, plus various bits of gear, and I plan to expand on my power generation (still small scale this year, hopefully massively with a grid connected ESS reselling power next year.)
My goal is to have 24/7/365 power output this year, even when my family isn't there. My current setup is as follows:
2x250w (damaged) solar panels on the south facing roof of the "utility" building. While they are damaged, I have seen output levels as high as 450w.
MultiPlus Compact 24/2000/50-30
BlueSolar Charger MPPT 150/45
In addition, I have about 35 watts of loads I want to run 24/7/365 (small esxi server, PoE switch, a few webcams, and GSM modem). The loads are a mix of AC and 24VDC. During the summer months I would prefer to have an addition ~100 watts of load constantly, but I am fine with shedding loads in low battery situations.
The area is prone to extreme winds and snow, when I was in the area and tried to check on it at Easter, there was 130cm of snow on the ground, making it impassible. The location is not quite Arctic, but it is a hair over 63 degrees north, so the shortest day of the year will be *VERY* short. In addition, the outdoor lows over the winter sometimes get to -35c.
I am looking at getting 4 new 275w panels, and while I know it will not be ideal, I would place 2 of them on the north facing roof, and two on the south facing wall under the roof line but as elevated as possible so that hopefully they will not get covered in snow over the winter. I expect that only the panels mounted vertically on the wall will have any meaningful output in the middle of winter. I am hoping to get enough output from them that this system can remain online year round, but I do not know if that is realistic.
Question 1) My "gut feeling" is that I should hook up each of the 3 pairs of panels so that each pair is in series, and each series of 2 is in parallel with eachother. Is this correct?
Question 2) Is there any good/easy solution for automatic load shedding at low power levels (such as a Venus controlled circuit breaker)?
Question 3) If it would help, I could actually put 3 panels on a south west facing wall, where they also may produce some power during winter, but they won't have any direct sunshine at any point. Is this of any value if I would have two panels in direct sunlight? Would the MPPT be limited to the current max from the string in direct sun, or would it actually benefit from some small additional current? What problems, if any, would having this sort of missmatched string size have? (all panels are 32v, so even a string of 3 is under the voltage limit for the MPPT)
Thanks in advance!