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Rebate Clock

iStore IS-BATT rebate

Checked against the approved list

IS-BATT 6.9, the smallest listed size

Waiting past 31 Dec 2026 costs $280

The 13.8 kWh IS-BATT gets the full rate on every kilowatt-hour. The 20.7 kWh size adds its extra capacity at 60%, so weigh its extra price against that smaller extra rebate.

Try your own numbers

Your battery and install date
Installed by 31 Dec 2026$1,840
Installed from 1 Jan 2027$1,560
Waiting costs you−$280

46 certificates × $40 for 6.9 kWh usable, at the May–Dec 2026 factor of 6.8. 39 certificates from 1 Jan 2027.

The factor is set by the date on the electrical compliance certificate, not the date you sign the quote.

19 batteries, every install date

Compare batteries
State and price
For state top-ups; the federal rebate is the same everywhere.
Price per certificate

The clock: this battery’s rebate by install date

  1. May–Dec ’26$1,840
  2. Jan–Jun ’27$1,560
  3. Jul–Dec ’27$1,400
  4. Jan–Jun ’28$1,240
  5. Jul–Dec ’28$1,120
  6. Jan–Jun ’29$960
  7. Jul–Dec ’29$840
  8. Jan–Jun ’30$680
  9. Jul–Dec ’30$560

How the size taper applies

  • First 14 kWh at 100%6.9 kWh
  • 14 to 28 kWh at 60%0 kWh
  • 28 to 50 kWh at 15%0 kWh

Get quotes from more than one accredited installer, and ask each to show the STC discount as its own line.

Updated 3 Oct 2026 · every figure links to its source · No provider pays us to be listed.

iStore's IS-BATT S1 comes in 6.9, 13.8 and 20.7 kWh, and the list records usable capacity equal to nominal.

IS-BATT rebate by install date

Size (usable)May–Dec ’26Jan–Jun ’27Jul–Dec ’27Jan–Jun ’28Jul–Dec ’28Jan–Jun ’29Jul–Dec ’29Jan–Jun ’30Jul–Dec ’30
IS-BATT 6.96.9 kWh$1,840$1,560$1,400$1,240$1,120$960$840$680$560
IS-BATT 13.813.8 kWh$3,720$3,120$2,840$2,520$2,240$1,960$1,680$1,400$1,120
IS-BATT 20.720.7 kWh$4,880$4,080$3,720$3,280$2,920$2,560$2,200$1,840$1,480
At $40 a certificate, excluding GST.

What each step up adds in 2026

SizeAddsRebatePer kWh
IS-BATT 13.8 6.9 kWh +$1,880 $272
IS-BATT 20.7 6.9 kWh +$1,160 $168

IS-BATT listings

SizeModel numberNominalUsableListed until
IS-BATT 6.9 IS-BATT-7000-S1 6.9 kWh 6.9 kWh 31 Dec 2027
IS-BATT 13.8 IS-BATT-14000-S1 13.8 kWh 13.8 kWh 31 Dec 2027
IS-BATT 20.7 IS-BATT-21000-S1 20.7 kWh 20.7 kWh 31 Dec 2027

How the IS-BATT sizes land on the taper

iStore's S1 sizes step up by 6.9 kWh. The smallest and middle sizes sit wholly in the full-factor band, the middle one just 0.2 kWh under 14 kWh; the 20.7 kWh size adds its last 6.9 kWh at 60%.

Per kilowatt-hour, the 6.9 and 13.8 kWh sizes earn almost the same. The 20.7 kWh size earns about 13% less per kilowatt-hour, because a third of it is in the 60% band.

Other iStore batteries on the list

iStore lists two generations side by side, S0 at 5, 10 and 15 kWh and S1 at 6.9, 13.8 and 20.7 kWh, all at 100% usable. The S1 steps are spaced so that the middle size falls just under the 14 kWh line.

Before you sign for a IS-BATT

  • Check whether the quote is for an S1 size (6.9, 13.8 or 20.7 kWh) or an older S0 size (5, 10 or 15 kWh). They sit under different listings with different expiry dates.
  • The 6.9 kWh S1 earns about half the 13.8 kWh rebate, so if you are near the line, compare the two on price after the discount.

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