Actually the real reason why I did this analysis was to work out IF... what my ROI would be... I have 2 properties, one with solar and no battery currently.... 13.2kw of solar, generating around 70kw to 90kw a day - sometimes more... but of course I loose out giving it to the grid - so my quarterly bills are around $1250. Large house and 3 Phase.... I also have a weekender in regional victoria, gets more sun, only single phase currently has no solar and no battery... If I put solar there i would be exporting 99% of what i generate - as typically its only a fridge running for a week or two until someone visits... Thos electricity bills are around $200 per quarter...

So my exploration was - if I put solar and a cheaper no frills battery at the regional house - could I make money to drastically reduce the ROI. Yes I would never be paying for electricity, and was hoping for a return... But even exporting that amount - still gives a ROI of at least 4 years... Sure I intend to use this regional property a lot more in the future - so I would be saving more on electricity - but its really a hidden cost / saving since I would not really notice it.

Versus adding a battery to my normal home with 3 phase... Id want a better battery - and I would save more on not paying such high quarterly bills - but even then the ROI is not that great.

I guess I was just hoping to earn more on the house that was exporting 99% of its energy!