4 May 2026 — Residential solar batteries usually cost between $
800–$1,300 per usable kWh installed.
So say $1000 per kWh.
One kWh of power from the grid down here in QLD costs about 33 cents on a flat rate but I have variables, Peak, off peak, and shoulder. The peak is 4pm till 8pm, the off peak from 10pm till 7am and the shoulder is basically through the day when my solar is running and that bit late at night. During the peak I don't run the oven or the A/C units so my usage costs are minimal, $22 for the last quarter. My last bill had a combined total grid draw of $96 for the quarter, 3 months, and that equates to just under $400 a year. That's the magic of Solar, it heats the H/W for free, runs the Washer and dishwasher and Vacuum cleaner and all the A/C units on the hot days.
So how long does a house battery last? 10 years? In your dreams. Perhaps 8 if it's full of good cells. It's constantly getting cycled remember. So $400x8 years = $3200. Get a 3kWh capacity one? Really pushing the margins, doable, but why bother with the power as cheap as it is. If you have a house with teenagers and a trophy wife you might make it work, with a 10 or 12 thousand dollar unit. The thing is, the future to ME is not about finding ways to maintain or Increase my consumption, quite the opposite. Residential solar is cheap here and makes sense but big lipo battery banks don't make sense, either from an economic standpoint or from an ecological one. It's not just $10 grand spent for a decade of overnight excess consumption, it's 5 grand spent mining the earth with diesel machines to make them too.
We need to Power Down a bit. Freeze the grids at the current levels and think about shrinking them in the years to come? Well no one wants that do they? GB has tons of wind and solar but it still gets 30% of its electricity from Gas, a fossil fuel that won't last forever. 50% of their power is from Gas, Imports, and Biomass, burning wood pellets, made from American forests and shipped over, "CARBON". Might as well just burn coal