A battery STC is the same small-scale technology certificate you already trade from rooftop solar. The difference is how it is created: instead of kW and a deeming period, the count comes from the battery’s usable kWh, a factor that falls over time, and size bands introduced on 1 May 2026. For an installer, the battery job is a normal sale with an unusually large certificate cheque hanging off it, which you fund until the trader pays.
This guide covers the full chain, from the certificate formula to the paperwork to the cash-flow gap, so you can price jobs correctly and avoid the claims that come back.
The formula
Certificates for a battery equal the usable capacity (capped at 50 kWh) multiplied by the STC factor for the installation date, with the size bands applied. At the time of writing:
- Factor: 6.8 for installs from 1 May 2026, then 5.7 from 1 January 2027 and 5.2 from 1 July 2027, stepping down every six months to 2030.
- First 14 kWh at 100 per cent of the factor.
- 14 to 28 kWh at 60 per cent.
- 28 to 50 kWh at 15 per cent.
Worked example: a 13.5 kWh battery
If the usable capacity is 12.8 kWh, that is what you use. 12.8 x 6.8 = 87.04, which rounds down to 87 STCs. At $38 that is about $3,306 and at $40 it is $3,480. If someone had used 13.5, they would claim 91 STCs and have a claim that does not reconcile with the product data.
Worked example: a 20 kWh battery
First 14 kWh: 14 x 6.8 = 95.2. Next 6 kWh at 60 per cent: 6 x 6.8 x 0.6 = 24.48. Total 119.68, so 119 certificates. At $38 that is about $4,522.
Check the exact rounding and factor on the Clean Energy Regulator (CER) site for your date. Our numbers are illustrations of the method.
What the product has to be
For the battery to create STCs it must be on the approved list, have 5 to 100 kWh of usable capacity, be capable of connecting to a VPP, and be installed by an accredited installer. The one-battery-per-property rule applies. Eligibility covers each in detail.
From install to cash
- Quote with a conservative STC price and the factor for the planned install date.
- Install and capture serial numbers, location, and photos to the required standard.
- Customer signs the assignment form before certificates are created.
- Claim is assembled: model, usable kWh, serials, photos, compliance and DNSP documents.
- Pre-check by your trader, if they offer it.
- Lodgement and validation in the REC Registry.
- Certificates are created and transferred to the trader.
- Payment at the trader’s rate, on their terms.
The discount you gave the customer on day one is paid back to you on day eight, or thereabouts. On a 10 kWh battery that is around $2,500 outstanding; on a 20 kWh job over $4,500. Multiply by the number of battery jobs in progress and the exposure becomes a working-capital line you should be tracking.
Why cash flow is the real battery question
On a typical solar job the STC value is a smaller share of the invoice. On a battery it is often 25 to 30 per cent. If your trader pays in 5 to 10 business days, four or five jobs in the pipeline can tie up more than $10,000. Faster settlement shortens that gap. We look at what is reasonable in how long STC payment should take.
Where claims go wrong
| Issue | Why it matters |
|---|---|
| Nominal kWh used | Claim overstates certificates and does not match product data |
| Model or variant not on the list | Certificates cannot be created |
| Serial unreadable in photos | Evidence rules from 1 March 2026 are stricter |
| Assignment unsigned or incomplete | Ownership of the certificates cannot transfer |
| Wrong install date | Factor and bands depend on it |
| Second battery at the property | One per property |
The wider pattern is in top STC claim rejection reasons.
Battery and solar on the same job
When a battery goes in alongside new solar you create two sets of certificates from two different calculations: solar from kW, zone rating and deeming period, battery from usable kWh and the factor. Keep the documentation separate so a problem with one does not delay the other. The deeming period explainer covers the solar half.
Pricing a battery job
Work backwards from what the customer will pay:
- Battery and installation cost
- Less certificate value at a conservative STC price
- Plus a buffer for a factor step if the install could slip
- Plus the cost of carrying the discount until you are paid
A job sold in December and installed in January should be priced at the January factor. If you absorb the difference you are cutting your own margin by several hundred dollars.
Reconciling what you were paid
When the payment arrives, check three numbers against your job record: the number of certificates, the rate, and any deductions. A trader’s statement should show STC count by job, so you can tie each payment to a specific installation. If a claim was reduced because of a capacity or date correction, you should see why. Keep the statement with the job file; it is also what you need for your own records and for the RCTI and GST treatment of the payment.
A note on audits
Battery jobs are higher value, and regulators look at higher-value claims with more interest. Keep the evidence for each job for as long as the rules require, in a form you can produce quickly: photos with intact metadata, signed forms, serials and compliance documents. How the process works is in how STC audits work.
What to do next
- Update your quote tool to use usable kWh, the bands and the installation-date factor.
- Build a battery photo checklist and use it on every job.
- Compare how fast your trader settles against the cash you carry on each job.
- For the full picture, see the battery STC pillar, the program overview, and our rates.
If you want a trader with a pre-check desk and 24-hour settlement for established partners, start trading with us and see how the process works.