DOE expands battery charger test procedure to wireless chargers


Recently, the Department of Energy (“DOE” or the “Department”) issued a final rule changing the test procedure used to demonstrate that battery chargers meet the energy efficiency requirements of 10 CFR § 430.32 (z ).[1] The final rule reorganizes some subsections of the testing procedure and includes several housekeeping revisions to, for example, fix cross-references and clarify symbology. More importantly, the final rule establishes a new Annex Y1 that expands the coverage of the test procedure to include all inductive wireless battery chargers, not just those designed for use in wet environments. The final rule also establishes a new measurement procedure for active, standby, and off modes, and updates the external power supply (“EPS”) selection criteria.

Since energy conservation regulations require that a test procedure regulation be finalized before a proposed rule amending or issuing a new energy conservation standard can be published, this final rule seems to signal the DOE’s intention to extend battery charger energy conservation standards to all wireless chargers. . Until such a rule is finalized, compliance with changes to the current battery charger test procedure in Appendix Y 10 CFR Part 430 will become mandatory effective March 7, 2023. Appendix Y will serve as a test procedure until the compliance date of any final version. rule establishing energy saving standards amended based on new Annex Y1.

Extended coverage of inductive wireless battery chargers

Currently, the battery charger energy conservation standards and test procedure only apply to inductive wireless battery chargers that have a battery energy of ≤ 5 watt-hours (Wh) and are designed and manufactured to operate in a humid environment. In other words, battery chargers in products like cordless toothbrushes and electric shavers. Due to advances in technology now used in wireless devices, the DOE is expanding the coverage of the new Appendix Y1 to include testing of wireless chargers intended for dry and wet environments and to differentiate these chargers based on the following definitions:

  • “fixed-location wireless chargers” or inductive wireless battery chargers that incorporate a physical receiver location feature (e.g., by a physical peg, cradle, locking mechanism, magnet, etc.) to align or repeatedly orienting the position of the receiver relative to the transmitter; and

  • “open-placed wireless chargers” or inductive wireless chargers that do not incorporate a physical receiver location feature (e.g., by a physical peg, cradle, locking mechanism, magnet, etc.) to align or repeatedly orient the position of the receiver relative to the transmitter.[2]

Additionally, the battery power rating limit of 5 Wh will increase to 100 Wh under Annex Y1 to reflect changes in the market. Indeed, as the DOE clarifies in the preamble, some fixed-location wireless chargers on the market are designed to charge products with energy levels up to ~80Wh (eg, power tools).[3] As such, the DOE believes that extending the limit to 100 Wh will support future product designs that may have larger battery energies.

It is important to note, however, that the scope of this extension applies to fixed-slot wireless chargers in all operating modes, but only applies to open-slot wireless chargers in batteryless mode.[4] Battery-free mode is a subset of sleep mode, where a battery charger is connected to the main power source, but no battery has yet been inserted. Although the DOE has considered expanding the test procedure to include active-mode testing for open-place wireless chargers, the Department has expressed concern about accounting for variations in efficiency measurements due receiver placement and non-battery-charging features—for example, foreign object detection circuitry—associated with these chargers.[5] The DOE continues to work with industry bodies to collect consumer usage data and develop an appropriate test procedure for testing open-place wireless chargers in active mode.[6]

Removed built-in UEC calculation

The DOE is also moving away from the integrated unit energy consumption (“UEC”) approach to measuring power consumption in active, standby, and off mode and moving to a mode-specific approach. In summary, the Energy Policy and Conservation Act (“EPCA”) requires the use of an integrated metric to measure overall energy efficiency, energy use or other energy descriptors, and consumption power consumption in sleep mode and off, unless the use of such an integrated metric is impractical.[7] In this case, the DOE has determined that the integrated UEC metric will become increasingly unmaintainable as the evolving nature of battery charger technology will require the Department to frequently update usage profiles for each class of charger. battery used as part of the built-in UEC calculation. . This would require manufacturers to retest and recertify their products at more frequent intervals.[8]

Therefore, Appendix Y1 will use a mode-specific approach that relies on a separate metric for each of the operating modes. Specifically, active mode energy (Ea) will be calculated from the combined charging and maintenance mode test and will be measured from the time the battery was first inserted or plugged in, until that the measured data indicates a power drop associated with the active load transition to maintenance mode.[9] Standby mode power (Psb), on the other hand, will represent the sum of the power of battery maintenance mode power (Pm) and battery-free mode power (Pnb).[10] Finally, the Off Mode (Poff) measurement will apply to products with manual on-off switches where the battery charger is connected to the main power supply, not connected to the battery and de-energized. Off-mode power consumption can also be measured for products with built-in batteries, for example, products that use a cradle and/or adapter for power conversion and charging. Appendix Y1 provides specific measurement procedures depending on the configuration.[11]

Introducing a new EPS selection hierarchy
Another change that can have a significant impact on a wide variety of consumer products is the modification of the criteria for selecting EPS under the test procedure in Annex Y1. It’s a common misconception that companies aren’t subject to DOE regulations if they don’t sell their products with an AC adapter. However, the test procedure defines a clear set of suitable test alternatives if an EPS is not provided. Note that these alternatives will change once Annex Y1 compliance is required.

The current test procedure specifies that battery chargers should be tested with either the EPS supplied with the charger or the EPS sold or recommended by the manufacturer. If there is no EPS that meets these requirements, the procedure calls for testing with a 5.0 VDC input for products powered by a computer USB port or using the midpoint of the voltage range nominal input for all other products. According to the DOE, these alternative test procedures produce unrepresentative results by (i) assuming 5.0 V DC input is appropriate for all products powered by a computer USB port or (ii) testing without EPS when battery chargers are operated with an EPS by consumers in the field. Based on this assessment, the Department modified the test procedure in Annex Y1 to improve its representativeness.

Specifically, Annex Y1 clarifies how manufacturers must select an EPS to demonstrate compliance with the battery charger energy standard when an EPS is not pre-packaged with the battery charger based on a hierarchy of selection. This hierarchy of alternatives is as follows: (1) an EPS sold and recommended by the manufacturer; (2) an EPS that the manufacturer recommends for use in the manufacturer’s materials; (3) any commercially available EPS that is both minimally compliant with the power conservation standard of 10 CFR § 430.32(w) and meets the EPS output criteria specified by the battery charger manufacturer.[12] Note that if the EPS used for certification testing is no longer available, DOE will test the battery charger with any minimally compliant EPS that meets performance criteria during compliance and application testing.

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According to the Department’s Spring 2022 Regulatory Program, we are awaiting a proposed regulation revising battery charger energy conservation standards and likely proposing standards alongside the new test procedure in Schedule Y1, to by April 2023. Please do not hesitate to contact us if you have any questions about the impact of the modified battery charger test procedure on your products.

[1] Energy Conservation Program: Test Procedure for Battery Chargers, 87 Fed. Reg. 55,090 (September 8, 2022).

[2] Identifier. at 55,126.

[3] Identifier. at 55,097.

[4] Identifier.

[5] Identifier.

[6] Identifier. at 55,097-8.

[7] 42 USC 6295(gg)(2)(A).

[8] 87 Fed. Reg. at 55,104.

[9] Identifier. at 55.106-7.

[10] Identifier. at 55,107.

[11] Identifier. at 55,130.

[12] Identifier. at 55,098-9.


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