ENERGY STAR® Program Requirements
for Products with Battery Charging Systems (BCSs)
DRAFT 2 Eligibility Criteria


Table of Contents



12 Section 1:



15 Section 2: Qualifying Products



18 Section 3: Energy Performance Specifications for Qualifying Products


20 Table 1: Energy Performance Criteria for Common Battery Voltages



23 Section 4: Test Methodology



26 Section 5:
Effective Date



29 Section 6: Future Specification Revisions


ENERGY STAR Program Requirements for Battery Charging Systems - DRAFT 2


ENERGY STAR Program Requirements
for Products with Battery Charging Systems (BCSs)
Eligibility Criteria
Below is the specification for ENERGY STAR qualified battery charging systems. Battery charging
systems consist of the combination of a battery charger and battery as defined below. Covered systems
may be either a battery charger with a detachable battery pack or a battery charger system functioning
with a product or appliance that is powered by an integral battery. A battery charging system must meet all
of the identified criteria if it is to be qualified as ENERGY STAR by its manufacturer.
While addressing a different set of product designs, this specification is intended to complement the
existing ENERGY STAR external power supply specification. Manufacturers shall carefully examine their
product designs and compare them to the detailed definitions (Section 1) and qualifying product
descriptions (Section 2) for a battery charging system and external power supply (visit') to determine the appropriate specification for ENERGY STAR
qualification. Manufacturers may only qualify individual models under the one specification (i.e., external
power supply OR battery charging system) that best reflects the power supply and product design. Note
that a qualified battery charging system may use an ENERGY STAR qualified external power supply, but
this is not sufficient or necessary to qualify the battery charging system as ENERGY STAR.
Note: EPA decided to cover the majority of battery charging systems, such as those found in small
household appliances and power tools, under a specification separate from external power supplies so
that power consumption needs unique to battery charging systems, including battery maintenance,
could be addressed. For some products, including cell phones and PDAs, the energy use profiles are
such that EPA saw significant energy savings potential by focusing exclusively on the external power
The external power supply specification applies to separable external power supplies designed to
convert line voltage ac into lower voltage ac or dc output. See www, energystar. gov/powersupplies for
the full definition. Product models meeting this definition shall be tested under the ENERGY STAR
External Power Supply Test Method and, where appropriate, qualified as ENERGY STAR under the
external power supply specification.
The battery charging systems specification, on the other hand, applies to: motor-driven battery charged
products; products whose principal output is heat, light, or motion; battery charging systems intended to
replace standard sized primary alkaline cells (e.g., AAA, AA, C, 9-volt, etc.); and other products (e.g.,
some digital cameras and camcorders) with detachable batteries and stand-alone battery chargers
whose designs are not covered by the external power supply specification. In the battery charging
systems specification, the battery may be either separable from or integral to the end-use product.
Please see below for the complete definition. Product models meeting this definition shall be tested
under the ENERGY STAR Battery Charging System Test Methodology (see Section 4) and, where
appropriate, qualified as ENERGY STAR under the battery charging systems specification.
Manufacturers are strongly encouraged to contact EPA with questions or uncertainties about ENERGY
STAR eligibility.
1) Definitions: Below are detailed definitions of battery charging systems and other related terms as
relevant to ENERGY STAR.
A. Battery (also Battery Pack): An assembly of one or more rechargeable cells intended to provide
electrical energy to an end-use product. Rechargeable cells are any of a number of established
cell chemistries intended for repetitive charge/discharge cycles. Primary alkaline cells are not
considered rechargeable. Batteries may be in one of the following forms:
ENERGY STAR Program Requirements for Battery Charging Systems - DRAFT 2

60	a) Detachable Battery: A battery that is contained in a separate enclosure from the end-use
61	product and is intended to be removed or disconnected from the end-use product for
62	recharging.
63	b) Integral Battery: A battery that is contained within the end-use product and is not
64	removed from the end-use product for charging purposes. A battery that is to be removed
65	from the end-use product for disposal or recycling purposes only is considered to be an
66	integral battery.
68	B. Battery Charger: A device intended to replenish the charge in a rechargeable battery. The battery
69	charger will connect to the mains at the power input and connect to the battery at the output. The
70	charger may be comprised of multiple components, in more than one enclosure, and may be all or
71	partially contained in the end-use product.
72	a) A La Carte Charger: A separable battery charger that is individually packaged without
73	batteries. Batteries that the a la carte charger is designed to charge should be listed on
74	the packaging, battery, and/or in the user materials.
75	b) Multi-Voltage Charger: A battery charger that, by design, may charge a variety of batteries
76	that are of different nominal voltages.
77	c) Multi-Port Charger: A battery charger that, by design, is capable of simultaneously
78	charging two or more batteries. These chargers also may have multi-voltage capability,
79	allowing two or more batteries of different voltages to charge simultaneously or
80	sequentially.
81	d) Stand-Alone Charger: A battery charger that, by design, charges separable batteries
82	disconnected from the end-use product.
84	C. Battery Charging System: A combination of battery charger and battery, detachable or integral,
85	which is intended to power a cordless product.
87	Device Types
88	D. Battery Operated End-use Product: Product or appliance fully powered by the battery at least part
89	of the time.
91	E. Cord/Cordless: Product or appliance that is designed to run on battery power, but also is designed
92	such that the product or appliance can run with a discharged battery when connected to the
93	mains.
95	F. Inductive Coupling: A system in which power is transferred between windings in two separate
96	enclosures through magnetic induction rather than metal-to-metal contact. This design limits the
97	possibility of electric shock or a short circuit and is often used in certain small household
98	appliances, such as cordless toothbrushes and shavers.
100	Operational Modes
101	G. Active Mode: The condition in which the battery is receiving the main charge, equalizing cells, and
102	performing other one-time or limited-time functions necessary for bringing the battery to the fully
103	charged state.
105	H. Battery Maintenance Mode: The condition in which the battery is still connected to the charger, but
106	has been fully charged. This mode may persist for an indefinite period of time.
108	I. Standby (No-Load') Mode: Lowest power consumption mode which cannot be switched off
109	(influenced) by the user and that may persist for an indefinite time when an appliance is
110	connected to the main electricity supply and used in accordance with the manufacturer's
111	instructions. Note: The standby mode is usually a non-operational mode when compared to the
112	intended use of the appliance's primary function.1 For the purposes of this specification, standby
113	mode is the condition in which no battery is present in the charger, or where the battery is integral
114	to a product, the product is not attached to the charger, but the charger is plugged in and drawing
115	power.
1 This definition is consistent with IEC 62301: Household Electrical Appliances - Measurement of Standby Power.
ENERGY STAR Program Requirements for Battery Charging Systems - DRAFT 2	3

Note: The above standby definition is consistent with IEC 62301. The standard is available at
116	Test/Measurement Terminology
117	J. Accumulated Nonactive Energy (Ea): The energy, in watt-hours (Wh), consumed by the battery
118	charger in battery maintenance and standby modes of operation over a defined period. For the
119	purposes of this specification, the 48-hour period consists of 36 hours of maintenance mode
120	operation followed by 12 hours of standby mode operation. The accumulated nonactive energy is
121	the sum of the energy used in these two modes.
123	K. Battery Capacity: The quantity of charge, measured in ampere-hours (Ah), capable of being
124	provided by a battery during discharge, the conditions of discharge being specified.
126	L. Battery Energy (Eb): The energy deliverable by the battery under known discharge conditions. For
127	the purposes of this specification and test methodology, the battery energy shall be measured at a
128	constant current discharge rate of 0.1 C. The test shall begin with a fully charged battery, and the
129	energy shall be measured until the battery reaches its manufacturer specified cutoff voltage, with
130	the cumulative total at the cutoff voltage being the battery energy. This value shall be reported by
131	the manufacturer and is subject to verification by EPA.
133	M. Nominal Battery Voltage (Vb): Industry standard cell voltage multiplied by the number of cells in
134	the battery pack. Nominal battery voltage is typically similar to measured open circuit terminal
135	voltage of a battery in a steady, fully charged state. Industry accepted nominal battery voltages for
136	applicable chemistries include: 1.2 volts for Nickel Cadmium and Nickel Metal Hydride; 2.0 volts
137	for sealed lead acid; and 2.5-4.2 volts for Lithium Ion (depending on material used for the positive
138	electrode and other factors).
140	N. Nonactive Energy Ratio (ER): The ratio of the accumulated nonactive energy (Ea) divided by the
141	battery energy (Eb). ER = Ea / Eb.
Note: Based on stakeholder feedback, several additions and revisions have been made to
Section 1, Definitions. The key changes include:
m Providing new definitions for battery charging systems, a la carte chargers, multi-voltage
chargers, multi-port chargers, and stand-alone chargers;
m Narrowing the scope of the inductive coupling definition to emphasize inductive coupling
systems used to transfer energy between two separate enclosures, as found in cordless
toothbrushes and similar products;
m Moving cell equalization from the battery maintenance mode definition to the active mode
m Deleting the rated battery capacity definition, as the term is not used in the specification and/or
the test methodology;
m Revising the nominal battery voltage definition for added clarity and to provide industry accepted
nominal battery voltages for applicable chemistries;
m Deleting the nominal battery energy definition and replacing it with a new battery energy
definition; and
m Changing the cord/cordless definition to account for devices powered by a dc wall plug
143	2) Qualifying Products: This ENERGY STAR specification applies to:
144	a) Battery charging systems packaged with portable, rechargeable products whose principal
145	output is mechanical motion, light, the movement of air, or the production of heat (e.g.,
146	small home appliances, personal care products, power tools, flashlights, and floor care
147	products); and
148	b) Products sold with a detachable battery and stand-alone battery charger (e.g., some
149	digital camera and camcorder designs, and battery charging systems intended to replace
150	standard sized primary alkaline cells including: AAA, AA, C, D, 9-volt, etc.).
152	In addition, battery charging systems must meet the following conditions:
ENERGY STAR Program Requirements for Battery Charging Systems - DRAFT 2	4

153	1. Chargers must be intended for rechargeable battery chemistries (e.g., Nickel Cadmium,
154	Lead Acid, Lithium Ion, and Nickel Metal Hydride) and not for primary cell chemistries
155	(e.g., alkaline "dry" cells);
156	2. Chargers may not rely on an inductive coupling system used to transfer energy between
157	two separate enclosures;
158	3. Batteries must have voltages less than 42 volts;
159	4. Chargers must have nameplate input power between 2 and 150 watts. (Nameplate power
160	is either the input power marked on the nameplate or the product of the nameplate
161	voltage and the nameplate current);
162	5. Charging systems must exclusively draw power for the purpose of charging a battery (i.e.,
163	chargers may not have a secondary functionality that draws power). These systems may,
164	however, draw power to provide a simple clock function;
165	6. All products must meet the ENERGY STAR requirements as packaged for sale. A la carte
166	chargers, which also may be multi-voltage and/or multi-port, may qualify as ENERGY
167	STAR if they meet the requirements when tested using all batteries identified/listed as
168	usable with the unit, as described in the ENERGY STAR Test Methodology.2 If the same
169	a la carte battery charger model also is packaged for sale with end-use products using
170	batteries, these systems may only qualify if the specific charger and battery combinations
171	also meet the ENERGY STAR requirements; and
172	7. Multi-port chargers may qualify if they meet the ENERGY STAR requirements with
173	multiple identical batteries as outlined in the ENERGY STAR Test Methodology. Similarly,
174	multi-voltage chargers may qualify if they meet the ENERGY STAR requirements with all
175	applicable batteries of differing voltages as outlined in the ENERGY STAR Test
176	Methodology.
178	The following types of battery charging systems are not covered by this ENERGY STAR specification:
179	1. Inductively coupled devices used to transfer energy between two separate enclosures;
180	2. Chargers with nameplate input power less than 2 watts; and
181	3. Charging systems that draw additional power to support added functionality such as
182	radios, CD players, and GFI AC outlets.
184	In order to qualify as ENERGY STAR, a model must meet the above parameters and the energy
185	performance criteria provided in Section 3, below.
187	Please note that single voltage external power supplies (including some that use the power supply's
188	dc output to charge batteries) and the end-use products they power are covered under separate
189	ENERGY STAR agreements ("ENERGY STAR Program Requirements for Single Voltage External
190	Ac-Dc and Ac-Ac Power Supplies" and "ENERGY STAR Program Requirements for End-Use Products
191	Using External Power Supplies"). Visit for additional information.
2 See Section 4 for "Test Method for Determining the Energy Performance of Battery Charging Systems (Draft, October 2005)."
ENERGY STAR Program Requirements for Battery Charging Systems - DRAFT 2	5

Note: Section 2 has been rewritten and reformatted to more carefully distinguish between products
covered by the battery charging systems specification and those that are not. Language has been
specifically added to allow multi-voltage, multi-port, and a la carte chargers to qualify as ENERGY
STAR when tested and evaluated as outlined in Section 5.1 of the ENERGY STAR Test
Methodology. Further, in this Draft 2 specification, EPA has excluded battery charging systems that
draw additional power for added functions outside of battery charging (e.g., radios, CD players, and
GFI AC outlets).
As suggested by stakeholders, EPA is proposing to exclude products with very low power
consumption, since the savings potential from such products would be very modest. EPA believes an
exclusion based on steady input power is preferred over one based on battery voltage. With this
approach, products designed for lower energy consumption will fit the exclusion, rather than products
designed to simply operate at a lower voltage, which are inherently less efficient.
Under this Draft 2 specification, EPA will continue to cover battery chargers intended to be unplugged
after charging. EPA understands that the instructions manual for these products advises consumers
to unplug them after recharging. However, this does not preclude EPA from recognizing the better
energy performers with an ENERGY STAR specification.
As suggested by a stakeholder, EPA revised the fourth bullet in Section 2 to refer to nameplate input
power rather than maximum input power, which would require a measurement method.
3) Energy Performance Specifications for Qualifying Products: To be eligible for ENERGY STAR
qualification, a battery charging system must not exceed a maximum Nonactive Energy Ratio, which
is based on the nominal battery voltage (Vb). The maximum allowed Nonactive Energy Ratios are
provided in Table 1 below for select battery voltages. For intermediate voltages, the battery charging
system must not exceed the maximum Energy Ratio associated with the next highest voltage
represented in the table. (Example: A product using a battery with a nominal voltage of 14.0 volts
would need to meet a maximum Energy Ratio of 3.7, consistent with the requirements for the next
highest voltage of 14.4, to qualify as ENERGY STAR.)
Table 1: Energy Performance Criteria for Common Battery Voltages
Given that multi-voltage and multi-port chargers require testing more than one battery pack, their
Nonactive Energy Ratios must be calculated differently. For these chargers, the Nonactive Energy
Ratio is calculated by taking the total accumulated energy from all tests and dividing by the sum of all
the tested battery capacities. The reference voltage used to identify the maximum allowable
Nonactive Energy Ratio is determined by averaging the battery voltages of all batteries tested. For
single-voltage, multi-port chargers, this calculation method leads to taking the total accumulated
energy from charging identical batteries and dividing by the sum of their capacities. The nominal
voltage of a single identical battery pack is then used to identify the maximum allowable Nonactive
Energy Ratio. Please refer to the ENERGY STAR Test Method for additional details.
ENERGY STAR Program Requirements for Battery Charging Systems - DRAFT 2

Note: In this Draft 2 specification, EPA has determined the energy performance requirements for
several reference battery voltages and calculated the Nonactive Energy Ratio for other voltages
through linear interpolation. EPA has provided a table with typical battery voltages (in multiples of
1.2 volts, as is typical in Nickel Cadmium and Nickel Metal Hydride cells), and proposes that
batteries with voltages that fall in between these typical values use the Nonactive Energy Ratio
associated with the next highest voltage in the table. The advantages of this approach are: 1) it
allows the Nonactive Energy Ratio to vary with the battery voltage; 2) it will be able to
accommodate future battery voltages that may not be built in increments of 1.2 volts; and 3) it
simplifies the qualification process by eliminating any calculations needed to determine the
qualifying Nonactive Energy Ratio.
Language has been added to Section 3 to briefly describe the Nonactive Energy Ratio calculation
for multi-voltage and multi-port chargers. Additional details are provided in the ENERGY STAR
Test Methodology.
Consistent with the ENERGY STAR guiding principles, the proposed specification represents the
top 25.7% of models from EPA's data set (26 out of 101), which includes 101 new power tool,
small household appliance, yard care, and personal care models.
A few stakeholders suggested that EPA add a power factor correction requirement to the
specification for chargers above 75 watts. To do so would require EPA to collect power factor data
on all tested models and then to likely redraw the specification levels. As such, EPA has decided
not to implement this change at this time. However, once the specification is finalized, power
factor data will be collected on qualifying models and analyzed for inclusion in a potential Tier 2
specification. This same approach is currently being employed for external power supplies.
EPA has decided to focus on Nonactive modes (i.e., battery maintenance and standby) because
they offer the largest potential for energy savings and can be consistently measured through a
robust and easy-to-use test method. While a total energy approach including Active mode has the
benefit of addressing all operational modes, it also would require usage scenarios/assumptions
per product area and may introduce measurement inconsistencies. EPA remains interested in
addressing Active mode and will continue to support research in this area.
EPA has chosen Energy Ratio as its performance metric because it allows data to be normalized
based on battery energy. EPA believes the proposed approach treats all product categories
4) Test Methodology: The specifics for testing the energy performance of a battery charging system are
outlined in a separate document titled "Test Methodology for Determining the Energy Performance of
Battery Charging Systems (Draft, October 2005)," which is available on the ENERGY STAR Web site.
The test results produced by this procedure shall be used to determine if a model qualifies as
ENERGY STAR. In addition, below are four ENERGY STAR-specific testing requirements.
Note: For a copy of the test methodology, visit the ENERGY STAR Web site at specs.battervcharqerdevelopment.
A. Safety Standards: ENERGY STAR qualified battery charging systems shall comply with applicable
local product safety requirements in the market(s) in which the product is to be sold. It is the
Partner's responsibility to ensure that its products meet acceptable standards of safety for battery
charging systems.
ENERGY STAR Program Requirements for Battery Charging Systems - DRAFT 2

Number of Units Required for Test: Testing shall be conducted by the manufacturer or its
authorized representative on three randomly chosen units of the same model. Manufacturers shall
report Energy Ratio values for all three units as well as the average values. To qualify as
ENERGY STAR, all three units must meet the ENERGY STAR specification; however, the
average of the three test values will be displayed on ENERGY STAR'S qualifying product list (see
Section 4.D below).
Models Capable of Operating at Multiple Voltage/Frequency Combinations: Manufacturers shall
test their products based on the market(s) in which the models will be sold and promoted as
ENERGY STAR qualified. EPA and its ENERGY STAR Country Partners have developed the
following table with three voltage/frequency combinations for testing purposes:
Supply Voltage:
North America/Taiwan:
115 volts ac, 60 Hz

230 volts ac, 50 Hz


100 Volts AC, 50 Hz or 60 Hz (either

frequency is acceptable)
For products that are sold as ENERGY STAR in multiple international markets and therefore rated
at multiple input voltages, the manufacturer must test at and report the required power
consumption, energy performance, or efficiency values at all relevant voltage/frequency
combinations. For example, a manufacturer that is shipping the same model to the United States
and Europe must measure, meet the specification, and report test values at both 115 volts, 60 Hz
and 230 volts, 50 Hz in order to qualify the model as ENERGY STAR in both markets. If a model
qualifies as ENERGY STAR at only one voltage/frequency combination (e.g., 115 volts, 60 Hz),
then it may only be qualified and promoted as ENERGY STAR in those regions that support the
tested voltage/frequency combination (e.g., North America and Taiwan).
Submittal of Qualified Product Data to EPA: Partners are required to self-certify those product
models that meet the ENERGY STAR guidelines and report information to EPA. ENERGY STAR
qualifying product lists, including new models as well as notification of discontinued models, must
be provided at least semi-annually. If no new models are introduced during a six-month timeframe,
manufacturer should notify EPA to ensure its partnership status is maintained.
Note: In response to stakeholder feedback, EPA has revised the test methodology for battery
charging systems. The document is available for review at specs.battervcharqerdevelopment.
The following minor changes to Section 4 are reflected in this Draft 2 specification:
¦ Rewording of Section 4. A, Safety Standards; and
m Modification of the Japanese frequencies to make it more clear that testing may be
performed at either 50 or 60 Hz.
EPA recognizes that the North American standard is set at 120 volts, 60 Hz per the National
Electric Code and the Canadian Electric Code. However, 115 volts, 60 Hz was deliberately
chosen for two reasons: 1) IEC Standard 62301 (standby power measurement methodology for
household appliances) uses this same voltage/frequency combination. As such, this combination
has been specified in other ENERGY STAR product specifications; and 2) EPA carefully vetted
this combination with its counterparts in Taiwan. Taiwan's government is a regional ENERGY
STAR program implementer whose voltage/frequency combination is 110 volts, 60 Hz. The
combination of 115 volts, 60 Hz was chosen to reduce the testing burden on manufacturers who
wish to qualify their products in both North America and Taiwan.
ENERGY STAR Program Requirements for Battery Charging Systems - DRAFT 2

258	5) Effective Date: The date that manufacturers may begin to qualify and promote battery charging
259	systems as ENERGY STAR will be defined as the effective date of the agreement. The ENERGY
260	STAR battery charging systems effective date is January 1, 2006.
Note: No changes have been made to Section 5, Effective Date in this Draft 2 specification.
Battery charging systems typically found in household appliances and power tools are currently
excluded from qualifying as ENERGY STAR under the external power supply specification; the
temporary exclusion ends on December 31, 2005. EPA is proposing that the new battery charging
systems specification take effect on January 1, 2006, which is immediately following the expiration
date for the exclusion. Once the battery charging systems specification is finalized, EPA will
update the external power supply specification to remove any references to the exclusion and to
add language directing stakeholders to the new battery charging systems specification.
262	6) Future Specification Revisions: EPA reserves the right to change the specification should
263	technological and/or market changes affect its usefulness to consumers, industry, or the
264	environment. In keeping with current policy, revisions to the specification are arrived at through
265	stakeholder discussions. In the event of a specification revision, please note that ENERGY STAR
266	qualification is not automatically granted for the life of a product model. To qualify as ENERGY
267	STAR, a product model must meet the ENERGY STAR specification in effect on the model's date of
268	manufacture. The date of manufacture is specific to each unit and is the date on which a unit is
269	considered to be completely assembled.
ENERGY STAR Program Requirements for Battery Charging Systems - DRAFT 2