What size battery do I need in Newcastle?

The single most common question we get, and the one most often answered badly. Battery size is not about your roof or your total consumption. It's about the power you draw when the sun isn't shining.

Start with your evening load

Look at your bill or, better, your smart meter data. Daytime consumption is largely covered by solar. The portion you use from late afternoon through to the next morning is what a battery displaces — and that's the number that sets the capacity.

The range most Newcastle homes land in

There is no dependable household-size rule. Use interval consumption, available solar, charging opportunities, desired backup duration and inverter output limits to establish nominal and usable capacity.

Why bigger isn't better

A battery only pays for itself on the energy it cycles. Capacity that sits unused every night is capital doing nothing. Oversizing is the most common way people end up disappointed with a battery's payback.

Things that change the answer

• An electric vehicle, now or planned — charging at home shifts the calculation considerably.
• Your energy plan: free or very cheap power windows make a fast-charging battery more valuable.
• Whether you want backup, and how much of the house you want backed up.
• Whether you're likely to add solar capacity later.

Sizing and discount eligibility

The CER currently applies a 100% STC factor from 0–14 kWh usable, 60% above 14–28 kWh and 15% above 28–50 kWh. AlphaESS capacities of 13.99 and 27.98 kWh sit close to two boundaries, but that does not guarantee that no incentive is wasted. Choose capacity for the property first and calculate eligibility under the rules current at installation.

Our estimator gives an indicative size in a couple of minutes. We confirm it against your actual bills before quoting — it's a starting point, not a promise.