Thought it would be useful to start a discussion about going off-grid or building an off-grid home in Victoria with a highly variable climate. Due to the low solar levels in winter the off-grid solar array needs to be oversized to account for poor winter conditions and a backup generator is almost always required (at least for the 3 winter months). This is much different to the climate in northern states like Queensland with much higher solar irradiation all year round.
Here is an off-grid solar system designed and installed by myself and Harpoon Electrics in Venus bay. This system has has a 9.15kW solar array with the rear string of panels tilted north at close to 45 deg to maximise solar generation during winter. There is also a 15kVA backup diesel generator.
I guess it depends on usage, but is there a general formula as to what percentage of panels you optimise for winter, vs summer for offgrid @Svarky ? With the panels that aren’t optimised for winter, do you optimise them for summer, or have them in between, or does it depend on the roof pitch you have to work with?
It really depends on the roof area and pitch. In this case it is a fairly flat north facing roof with 12 deg pitch and not enough room to tilt both rows of panels. If the front row was tilted it would have partially shaded the rear panels in winter which would be terrible for performance.
However on cloudy days the panel tilt angle doesn’t really matter so the more panels the better. This was the best combination of both high and low tilt angles to fit with the inverter specifications and customer budget.
@HardyMaria sounds like you need to upgrade to a pure sign wave inverter. They are very cheap compared to a few years ago. If you can afford it I’d recommend one of the Victron inverters.
