UL 9540, UL 1973, UL 2743 and more: energy storage certifications explained
Which certification applies to a home battery, a portable power station or an inverter, what each one proves, and how to check a listing.
The short version
- UL 9540 certifies a complete energy storage system; UL 1973 the battery inside it; UL 2743 portable power stations.
- UL 1741 (US), AS/NZS 4777.2 (Australia) and VDE-AR-N 4105 (Germany) cover how inverters and batteries behave on the grid.
- In Australia, only batteries and inverters on the official approved lists qualify for installation incentives.
- A certificate is only as good as its listing: check the exact model in the issuing body's register.
Why certification matters
A lithium battery stores a lot of energy in a small space, and the electronics around it decide whether a fault stays a fault or becomes a fire. Certification shows that a product of that exact design was tested by an independent laboratory against a published standard, and that the factory is inspected to keep building it the same way. For installed systems it is not optional: building codes, grid operators, insurers and incentive schemes require it. PowerTrusted shows the certifications of 1,518 product ranges as verified against the official registers.
Which certification applies
| Product | United States | Australia | Germany | All markets |
|---|---|---|---|---|
| Portable power station | UL 2743 | – | – | UN 38.3 |
| Home battery (installed) | UL 9540, UL 1973 | CEC Approved Battery | VDE-AR-N 4105 | UN 38.3 |
| Solar or hybrid inverter | UL 1741 | CEC Approved Inverter | VDE-AR-N 4105 | – |
| Plug-in solar / balcony battery | – | – | VDE-AR-N 4105 | UN 38.3 |
United States: UL 9540, 1973, 2743, 1741
UL 9540 is the system-level safety standard for energy storage systems: battery, inverter or power conversion, controls and enclosure, tested together. US residential codes (IRC R328 and NFPA 855) require installed home batteries to be listed to UL 9540. In PowerTrusted's library, 252 home battery ranges hold it.
UL 1973 covers the battery itself, at module and pack level. It is a building block of UL 9540, not a substitute for it: a UL 1973 battery paired with an inverter still needs the combination listed to UL 9540 to be installed as a system (257 ranges in the library). A related document, UL 9540A, is a test method rather than a certification: it measures how a fire in one cell spreads, and its results decide installation spacing and location.
UL 2743 is the standard for portable power packs, the category portable power stations belong to. Its scope ends at 20 kWh of lithium-ion capacity; larger systems fall under UL 9540. A portable station that will be connected to a home's wiring through a transfer switch should be checked against the installation rules for energy storage, not only UL 2743.
UL 1741 covers inverters and other grid-interconnection equipment. Its supplements SA and SB add the grid-support functions US utilities require, including California's Rule 21. Inverters and hybrid inverters connected to the grid need it (385 inverter ranges in the library, from the California Energy Commission's equipment lists).
Australia: the approved lists
Australia uses product lists rather than a single mark. Grid-connected inverters must comply with AS/NZS 4777.2 and appear on the approved inverter list; batteries must appear on the Clean Energy Council's approved battery list to be installed by accredited installers and to receive certificates under the Cheaper Home Batteries Program. Each listing carries a certificate number and an expiry date, so a product can drop off the list. PowerTrusted shows 268 approved battery ranges and 412 approved inverter ranges, with the listing date checked.
Germany: VDE-AR-N 4105
Generators and storage connected to Germany's low-voltage grid, from rooftop inverters to home batteries and the inverters of balcony power plants, need a unit certificate against VDE-AR-N 4105, which defines how they behave on the grid and disconnect when it fails. Plug-in solar devices must also meet the product standard DIN VDE V 0126-95; see our guide to balcony solar in Germany.
Everywhere: UN 38.3
Every lithium battery, from a power bank to a home battery module, must pass the UN 38.3 test series before it can be shipped by air, sea or road: altitude, thermal cycling, vibration, shock, short circuit and overcharge. It is a transport requirement rather than a product safety certification, but a supplier unable to provide the UN 38.3 test summary cannot legally ship the product.
How to check a certificate
- Find the exact model. A listing covers specific model numbers; a certificate for a battery module does not cover a complete system, and one for a different capacity is not the same product.
- Search the register. UL listings are searchable in UL Product iQ; the California Energy Commission publishes its solar equipment lists; Australia publishes the approved battery and inverter lists.
- Check the dates. Listings expire and are withdrawn. A certificate PDF from the seller shows that a test took place; the register shows whether it is current.
- Check the laboratory. In the US the testing laboratory must be a Nationally Recognized Testing Laboratory; the mark names it and carries a file number.
On PowerTrusted, certifications marked Verified were checked against the official register on the date shown on the product page.