In SA it has been quite expensive to install a battery. I have 14.2 KW of solar and it is not economical still to have a battery. I did see an advert of 20 kw for around $13k installed, then tonight a name I had not heard of popped up with a "deal" that you need to enquire about, that is 20kw for $9k. But they do things different I think, as they plug into solar panels first. Unsure how it all works as I am not tech savy LOL Victoria has amazing battery deals as subsidized by the government But for those into tech stuff here is the website Solar Battery Storage Solutions | Save Energy |