Home Battery Payback Calculator (SA 2026) - Honest Numbers

Q: Does it include VPP ongoing credits?

No - only the upfront REPS incentive. Ongoing VPP credits improve the real-world return beyond what this calculator shows.

What this does: Enter your power bill and a battery size, and this calculator estimates your rebates, net cost, annual saving and payback in years – using June 2026 SA rebate figures and honest assumptions you can see below. No email required.

Battery payback calculator

Your typical quarterly power bill ($) Battery size (usable kWh) Share of your power used in the evening: 60%

Your peak grid rate (c/kWh) Your feed-in tariff (c/kWh) Concession card holder (higher REPS amount) Will join a Virtual Power Plant (unlocks REPS)

–Total rebates (est.)

–Net battery cost (est.)

–Annual saving (est.)

–Payback

How the calculator works

Most battery calculators are black boxes built to make every answer “buy now”. This one shows its working. It takes your bill, works out how much power you buy in the evening, and assumes a battery can shift that usage onto stored solar at 90% efficiency. The saving is the gap between your peak rate and your feed-in tariff – that’s the real margin a battery earns. Rebates come off the typical installed price first: the federal Cheaper Home Batteries discount (about $252 per usable kWh to 14kWh as of June 2026) and an SA REPS estimate that scales with battery size rather than pretending everyone gets the $2,050 cap.

What it can’t know

Your actual tariff structure – time-of-use plans change the maths, usually in a battery’s favour.
Your switchboard and roof – some homes need extra electrical work that adds to the quote.
VPP credits – ongoing Virtual Power Plant payments improve payback beyond what’s shown here.
Backup value – keeping the lights on through a blackout is worth something, but it isn’t a bill saving.

⚡ The federal battery rebate steps down again at the start of 2027 - worth around $400 less on a 10kWh battery. The same system costs more the longer you wait.

Want it checked against your real bills?

A good installer models payback from your actual usage data, not estimates. We’ll connect you with one licensed local installer – exclusively, not shared with five.

Get my payback checked properly - free

Exclusive - your details go to one licensed local installer, not five.

Payback calculator FAQs

How accurate is this calculator?

It’s an honest estimate, not a quote. The biggest unknowns are your tariff structure and exact evening usage. Treat the result as a guide to whether a battery is worth pursuing, then have an installer model it from your real bills.

Why does my payback change so much with the evening-use slider?

A battery only saves money on power you’d otherwise buy at peak rates. If most of your usage is in daylight while solar is generating, there’s less expensive evening power for the battery to offset – so payback stretches out.

What rebate figures does it use?

The federal Cheaper Home Batteries Program at about $252 per usable kWh for the first 14kWh (June 2026 rate, stepping down January 2027), and an SA REPS VPP estimate of roughly $73 per kWh capped at $2,050, with about 30% extra for concession holders.

Does it include VPP ongoing credits?

No – only the upfront REPS incentive. Ongoing VPP credits (bill credits or per-event payments) improve the real-world return beyond what this calculator shows.