The 2025 edition of UL 2743 has been officially implemented, introducing key changes including UPS function compliance requirements, specifications for backpack-style power packs, and clarification of battery classifications. With comprehensive upgrades to testing standards and applicable scenarios, it poses new compliance challenges for portable energy storage power enterprises.

Key Updates & Specific Requirements

1. Addition of UPS Standards for Power Packs with Bypass Source FunctionPower packs featuring a bypass source function shall comply with the UPS standards UL 1778/CSA C22.2 No. 107.3.

2. 1.5 Additional Requirements for Backpack-Style Portable Power PacksThese requirements cover portable power packs integrated into or attached to luggage, carrying cases, bags, or backpacks. They do not address the performance of the luggage, carrying cases, bags, or backpacks themselves.

3. 5.16, 5.20, 5.28 Clarification on Requirements for Removable or External Battery Packs

• Removable Battery: A battery that can be disassembled without tools.
• External Battery: A battery that is independently packaged in a separate enclosure and connected to the portable power supply via wires.
• Internal Battery: A battery that is partially or fully contained within the enclosure of the portable energy storage power supply, or permanently fixed and used to provide short-term power output.

4. 12.1.3 Minimum UL 1778 Requirements for UPS-Function Power PacksPower packs with UPS functionality shall also meet the applicable requirements of UL 1778/CSA C22.2 No. 107.3. As minimum requirements, the following sections shall be considered:a) Feedback protection and the Feedback Protection Test Appendix;b) Provisions for grounding and connections, and the Grounding and Connections Appendix;c) Overcurrent and ground fault protection in the main circuit;d) Abnormal operation and fault conditions;e) Appendix Additional Component Requirements;f) Harmonic distortion testing; andg) For lead-acid batteries, ventilation of battery compartments.

5. 12.2.1 Cable and Plug ConnectionsPlugs capable of continuous load-bearing for 3 hours or more shall not exceed 1.25 times the product’s rated input parameters; the installation instructions shall include complete specifications for the correct selection of power cord sets, or comply with the following: A cord set or power-supply cord consisting of a connecting plug complying with UL 817 or UL 498, and a flexible cord complying with UL 62.

6. 12.5 Clarification on Photovoltaic Input Structures with Hazardous Voltage LevelsPower packs equipped with photovoltaic panels as the input source for charging internal batteries, where the rated voltage exceeds the hazardous voltage level defined in 5.26 or the energy exceeds the hazardous energy level defined in 5.25, shall be equipped with an inverter and/or charge controller, and shall meet the applicable requirements of UL 1741; or comply with the applicable requirements of UL 62109-1.

7. 13.3 Reduced Requirements for Output Outletsc) For power packs with AC bypass functionality, compliance shall be determined in accordance with the applicable requirements of UL 1778/CSA C22.2 No. 107.3. See 12.1.3.

8. 15.1.12 Revision/Clarification of Protective Connections via Printed Circuit Board (PCB) TracesThe main grounding path shall not include traces on a PCB.

• Exception 1: PCB traces used as protective bonding conductors shall be evaluated in accordance with the impedance test and limited short-circuit test specified in CSA C22.2 No. 0.4, Bonding for Electrical Equipment.
• Exception 2: PCB traces used as protective bonding conductors shall be evaluated in accordance with the bonding conductor test specified in UL 1012, Standards for Power Units Other Than Class 2.

9. *30.2 Internal Lead-Acid or Valve-Regulated Nickel BatteriesLead-acid or valve-regulated nickel batteries shall comply with the requirements for portable applications in UL 1989 or UL 1973.

10. *30.3 Internal Lithium-Ion or Sodium-Ion BatteriesSodium-ion battery cells shall comply with UL/ULC 2580 or UL 1973 requirements.

11. 30.4 Battery Pack Exemptions and Certification RequirementsInternal lithium-ion and sodium-ion battery packs that meet UL 2595/CSA C22.2 No. 0.23 are exempt from Clauses 46 and 47. External battery packs exceeding 1 kWh shall be certified to UL 1973. For those below 1 kWh, compliance with UL 2595/CSA C22.2 No. 0.23 is an acceptable alternative.

12. 31.6 Pollution Degree for Indoor/Outdoor Power PacksPower packs are considered suitable for use in Pollution Degree 3 environments for outdoor or temporary outdoor applications; and Pollution Degree 2 environments for indoor applications. Sealed or encapsulated enclosures, or PCBs coated in accordance with UL 840, Performance Testing of Coatings for Printed Wiring Boards for Electrical Equipment Insulation Coordination Including Clearances and Creepage Distances, and CAN/CSA C22.2 No. 0.2, Insulation Coordination, are deemed to meet Pollution Degree 1.

13. 35 Feedback ProtectionPower packs utilizing AC pass-through functionality shall comply with the feedback protection test requirements specified in the Appendix of UL 1778/CSA C22.2 No. 107.3.

14. 49 Leakage Current Testing

• Exception 1: For power packs without an AC power supply, leakage current shall be measured using an instrument connected between the output ground terminal and any user-accessible conductive component. Additionally, there shall be no electric shock hazard between hazardous circuits (input or output) and the output ground terminal and/or any user-accessible conductive component, see 5.42.
• Exception 2: For power packs with AC pass-through functionality, the leakage current in the protective bonding conductor shall not exceed 3.5 mA in accordance with the applicable requirements of UL 1778/CSA C22.2 No. 107.3.

15. *50.9 Battery Reverse Polarity Testing

16. 55.10.1 Testing for Power Packs with Removable/External BatteriesFor power packs with removable internal batteries, removable external batteries, or external-connected batteries that lack locking devices or other measures to prevent incorrect connection, the test specified in 55.10.2 shall be conducted, and the power pack shall comply with the requirements of 55.1.1.

17. 60.3 Revised Mobile Drop Test for Wheeled Power Packs

• Samples of portable power packs weighing 18 kg (39.7 lbs) or less shall be dropped three times from a height of 0.9 meters (3 feet) onto the most unfavorable impact location on a concrete surface.
• Samples of mobile power packs weighing more than 18 kg (39.7 lbs) and equipped with handles shall be dropped once from a height of 0.9 meters (3 feet) onto the most unfavorable impact location.
• Exception: Samples of mobile power packs weighing more than 25 kg (55.1 lbs) and designed with wheels for mobility shall be dropped once from a height of 0.5 meters (1.6 feet) at the intended use position to simulate a sudden fall from a vehicle and test performance.

18. 70.1 Peak Discharge Current Rating TestingPower packs with enhanced functionality shall undergo an ampacity test:

• For lead-acid or valve-regulated nickel battery packs: Load at the manufacturer-specified maximum discharge current or power for 10 seconds until the discharge cut-off voltage reaches 7.2V.
• For lithium-ion or sodium-ion battery packs with protective circuits: Conduct a 5-second ampacity test, loading at the manufacturer-specified maximum discharge current or power until the battery pack reaches its minimum withstand discharge cut-off voltage. If the capacity is lower than that of the 10-second test, the ampacity rating and the duration of ampacity output shall be included in the battery pack’s ratings.For lead-acid or valve-regulated nickel battery packs, the test duration shall be within 2 seconds; for lithium-ion or sodium-ion battery packs, the test duration shall be less than 5 seconds. The current capacity shall be recorded during and at the end of the test, and the final value shall serve as the battery pack’s ampacity rating.

19. 70.2 Declaration of Peak Discharge Current RatingIn addition to the maximum discharge current rating, if the manufacturer declares a peak discharge current rating for power packs with boost functionality, the ampacity test shall be repeated by loading the power pack at the peak discharge current at the output terminals (at the clamps) for 100 milliseconds or the manufacturer-specified duration, whichever is longer. The declared peak current rating and the duration of peak current output shall be included in the power pack’s ratings. The current value shall be recorded during and at the end of the test, and the final value shall serve as the power pack’s peak current rating.

20. 71 Feeding TestUnder normal operation and single fault conditions, and 1 second after the power pack enters energy storage mode (when not connected to a power source), the voltage at the input connection shall not exceed 60V DC, or the available current shall not exceed 3.5 mA.

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