Hi everyone,
I recently moved into a house that came with a pre-installed 6.6 kW solar system (installed in 2021), consisting of 19 panels—around 7 facing east and 12 facing west.
However, in 2024, a double-storey house was built next door on the west side, and it now heavily shades the west-facing panels during the winter months (April through August), which has significantly impacted generation.
I’m now considering adding battery storage (around 20 kWh) and potentially expanding the solar system. The simplest option I’m exploring is adding another 6.6 kW system with all panels facing east to pair with the battery.
A few questions I’m hoping the community can help with:
Would it be worth relocating the existing west-facing panels to the east side (in addition to adding new panels), considering the west-facing ones are now heavily shaded in winter?
Would it make sense to replace the existing 5 kW inverter with a 10 kW one and integrate the new panels into the existing system? I’m concerned this might raise warranty issues, as the original installer could attribute any future performance problems to the modified setup.
Would really appreciate any insights or recommendations based on your experience.
Thanks in advance!
There is no universe where you are going to break even here. Seriously, how much power do you use?
If you add a battery, more north facing panels are your best option as the middle of the day is when you are pushing most of your generation into the batteries, however I assume that you have an east/west roof line which will make this difficult if not impossible.
Good luck moving your panels from the west to the east. Seriously, how much roof space do you have to play with? Either way, given the subsidies available you will likely find that it's more cost effective to just add more panels. The existing inverter will be programmed to ignore any generation over 5kW anyhow.
Have you checked if your 5kW inverter is even compatible with a battery system? Many installed in 2021 will not be. Best case they will be brand bound.
Generation is pretty crap in the winter months either way. The number of hours you are generating is low, and you're pushing reduced generation per panel even in the middle of the day.
The economics of this is currently that you have a free (ie already paid for) solar system, verses adding extra kWh for… what exactly? Are you trying to disconnect from the grid entirely? At best you are reducing your shoulder costs only, because even 5kWh is enough generation at maximum capacity for most standard households in the middle few hours of the day.
Anything you spend now… a new inverter before the end of its life, a new battery even with subsidies… all of that is going to have to cover the extra few off the grid kWh units that you will end up paying for up front as a capital cost.
My advice is just to ride your current system until it fails (likely the inverter, at 10-15 years) and then explore options for an upgrade then.