Solar Panel & Battery Set Up

Hi all, With the introduction of rebates in WA and the Federal Gov rebate, I’m looking to upgrade my current 3.64kW solar panel set up to something with batteries.

I emailed 3 companies, 2 of them asked for some info on my existing system (which I replied to). Doing some research, I was looking to get a 7-10kW/h system but mentioned I was open to advice.

Unfortunately my solar panels were installed before 2016 so I will need to replace them, which I accept.

The one place that came back to me with a quote recommended a 11.44kW solar panel set up with a 19.2kW/h battery - total cost $20 inc the rebate.

I’m living in a 3 bedroom & 2 bathroom. My average energy usage is 3.55 units a day, my last power bill was $85. I have an evaporative air con system to cool the house in summer. In terms of future plans, perhaps change my gas heating / cooker to electric but that won’t be for a while since I have other renovations I’m planning (double glazing and insulation).

I doubt that I would have enough roof space for the solar panels and think the batter size is excessive. Also, they pointed out that there is a higher rebate for bigger systems so I’m wondering if they just trying to upsell.

So just wondering what you all think.