Battery certifications and testing: What you need to know

Like other electronic products, home batteries undergo rigorous testing before installation and use at home or business. These tests are critical to determining the quality and performance of batteries under particular environmental stresses and confirming they meet mandated government safety requirements. In this article, we'll review today's most common testing and certifications for home batteries.

Battery testing and certification ensure home storage systems' quality and safety. A battery constantly has energy being cycled in and out of it, and that puts a real strain on the chemical and mechanical systems that keep batteries functional and safe. Testing and certifying batteries by internationally recognized standards ensures you get a high-quality product that will deliver when needed.

While reviewing a home battery spec sheet, you'll likely notice a bunch of acronyms and random numbers listed under safety and rating certifications – what do these mean? Below are some of the most common battery testing standards and certifications to look for when comparing home batteries.

UL 9540: Energy Storage Systems and Equipment

This is an overall certification for what UL calls "Energy Storage Systems" - ESS for short. A UL 9540 ESS has a UL 1973-certified battery pack (more details below) and a UL 1741-certified inverter (also more information below). It is designed to certify complete systems so you can be sure your battery setup is configured correctly, and its parts all work in harmony.

UL 1741: Inverters, Converters, Controllers, and Interconnection System Equipment for Use With Distributed Energy Resources

As we mentioned above, UL 1741 is an inverter-specific product safety standard. It lays out manufacturing and product testing requirements for inverters to ensure they can manage grid reliability functions and handle electric grid changes. Within the UL 1741 certification are several tests, such as the anti-islanding test, which ensures the inverter can disconnect from the grid when appropriate. This and several other testing protocols all attempt to ensure that inverters can operate during normal and abnormal grid conditions.

UL 1973: Standard for Batteries for Use in Stationary, Vehicle Auxiliary Power, and Light Electric Rail (LER) Applications

UL 1973 is the battery-specific version of UL 1741 in that it certifies the ability of a battery system to withstand normal and abnormal conditions. It specifically does not evaluate any performance or reliability measures of a battery.

UL 1642: Lithium Batteries

This standard by UL is a lithium battery-specific testing standard, and it tests the risk of fires and explosions (both very, very rare in batteries - partly due to standards like these!).

UL 2054: Household and Commercial Batteries

UL 2054 is a general battery safety standard by UL. It contains 18 tests that products must pass, including seven electrical tests, four mechanical tests, and even a fire exposure test. Specifically for lithium batteries, this standard defers any component cell level testing to UL 1642, mentioned above.

UL 62133: Safety Requirements for Portable Sealed Secondary Cells

UL 62133 is the Underwriters Laboratory version of IEC 62133, a globally recognized battery safety standard by the International Electrochemical Commission (IEC for short). The IEC has many more solar panel certifications than battery certifications, but IEC 62133 was one of the most important battery standards out there for many years. UL 62133 is essentially the same thing, just from a different company. It's been suggested that UL 62133 may replace UL 1642 and UL 2054 at some point, but we haven't gotten there yet.

Are you shopping for solar and storage equipment that meets the above certifications? Head over to the EnergySage Buyer's Guide, where you can compare different types of equipment based on efficiencies, warranties, and more. On each product page, we've listed the passed tests and certifications for each battery, so you don't have to dig through the spec sheets! Once you're ready to see offers from local installers, sign up on the EnergySage Marketplace to receive free online solar quotes from local installers.