timmmay:

 

EgorNZ:

 

I'm not sure how significant the difference in inverter efficiency is. But I would've thought 6kW is undersized for 9.2kW of panels.

 

Get as many panels as will fit on your roof would be my advice.

 

Assume you've seen this thread, the Shelly relays aren't suitable for driving a HWC directly:

 

https://www.geekzone.co.nz/forums.asp?forumid=73&topicid=304656&page_no=2#3216750

 

 

6kw with 6kw peak output and I think it can go a little higher, according to the specs. The question is around ROI mostly - would spending another $1600 on a larger inverter be worthwhile given the additional 2kw peak generation that will happen a couple of hours per day when the weather is perfect. Given the weather in Wellington isn't usually perfect, though we're having a great run at the moment, I suspect it would probably work ok.

 

Thanks for pointing out the Shelly issue, a contactor seems essential. That puts the price up quite a bit, $300 ish instead of $100 ish. I wonder if I'd be better off just using the digital timer I have there now, even though there's no HA control.

 

It would seem to me , that the extra money spent on a larger inverter would take around 6 years or so to pay off with generation. I wanted extra panels for my system at the time, but was limited in the strings. So have the panel matching the inverter. Another 2-3kw of panels would make the biggest difference in winter for us. Our system does the nice curve on a perfect day, but with more panels, would then have a flat line for a while, which is fine also.

The most important aspect, is it helping out and doing what you are expecting with a power bill reduction.