ENERGYSTAR
ENERGY STARŪ Program Requirements
for Products with Battery Charging Systems (BCSs)
Eligibility Criteria
Table of Contents
Section 1: Definitions 2
Section 2: Qualifying Products 4
Section 3: Energy Performance Specifications for Qualifying Products 5
Table 1: Energy Performance Criteria for Common Battery Voltages 5
Section 4: Test Methodology 5
Section 5: Effective Date 6
Section 6: Future Specification Revisions 6
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ENERGY STARŪ 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
www.enerqvstar.gov/powersupplies) 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.
1) Definitions: Below are detailed definitions of battery charging systems and other related terms as
relevant to ENERGY STAR.
General
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:
a) Detachable Battery: A battery that is contained in a separate enclosure from the end-use
product and is intended to be removed or disconnected from the end-use product for
recharging.
b) Integral Battery: A battery that is contained within the end-use product and is not
removed from the end-use product for charging purposes. A battery that is to be removed
from the end-use product for disposal or recycling purposes only is considered to be an
integral battery.
B. Battery Charger: A device intended to replenish the charge in a rechargeable battery. The battery
charger will connect to the mains at the power input and connect to the battery at the output. The
charger may be comprised of multiple components, in more than one enclosure, and may be all or
partially contained in the end-use product.
a) A La Carte Charger: A separable battery charger that is individually packaged without
batteries. Batteries that the a la carte charger is designed to charge should be listed on
the packaging, battery, and/or in the user materials.
b) Multi-Voltage Charger: A battery charger that, by design, may charge a variety of batteries
that are of different nominal voltages.
c) Multi-Port Charger: A battery charger that, by design, is capable of simultaneously
charging two or more batteries. These chargers also may have multi-voltage capability,
allowing two or more batteries of different voltages to charge simultaneously or
sequentially.
d) Stand-Alone Charger: A battery charger that, by design, charges separable batteries
disconnected from the end-use product.
e) Batch Charger: With some multi-port chargers, such as universal AA battery chargers,
single cells are charged in batches (i.e., groups of batteries charged in series). For the
purposes of this specification, each of these batches shall be treated as a discrete battery
pack. For example, a AA Nickel Metal Hydride charger with four ports may charge in two
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batches, with the batches connected in parallel. Each batch, in this case, would be treated
as a single 2.4V battery pack. Charging four AA batteries in this system would be
considered, for the purposes of this specification, as a multi-port charger charging two
2.4V batteries in parallel.
C. Battery Charging System: A combination of battery charger and battery, detachable or integral,
which is intended to power a cordless product.
Device Types
D. Battery Operated End-use Product: Product or appliance fully powered by the battery at least part
of the time.
E. Cord/Cordless: Product or appliance that is designed to run on battery power, but also is designed
such that the product or appliance can run with a discharged battery when connected to the
mains.
F. Inductive Coupling: A system in which power is transferred between windings in two separate
enclosures through magnetic induction rather than metal-to-metal contact. This design limits the
possibility of electric shock or a short circuit and is often used in certain small household
appliances, such as cordless toothbrushes and shavers.
Operational Modes
G. Active Mode: The condition in which the battery is receiving the main charge, equalizing cells, and
performing other one-time or limited-time functions necessary for bringing the battery to the fully
charged state.
H. Battery Maintenance Mode: The condition in which the battery is still connected to the charger, but
has been fully charged. This mode may persist for an indefinite period of time.
I. Standby (No-Load') Mode: Lowest power consumption mode which cannot be switched off
(influenced) by the user and that may persist for an indefinite time when an appliance is
connected to the main electricity supply and used in accordance with the manufacturer's
instructions. Note: The standby mode is usually a non-operational mode when compared to the
intended use of the appliance's primary function.1 For the purposes of this specification, standby
mode is the condition in which no battery is present in the charger, or where the battery is integral
to a product, the product is not attached to the charger, but the charger is plugged in and drawing
power.
Test/Measurement Terminology
J. Accumulated Nonactive Energy (Ea): The energy, in watt-hours (Wh), consumed by the battery
charger in battery maintenance and standby modes of operation over a defined period. For the
purposes of this specification, the 48-hour period consists of 36 hours of maintenance mode
operation followed by 12 hours of standby mode operation. The accumulated nonactive energy is
the sum of the energy used in these two modes.
K. Battery Capacity: The quantity of charge, measured in ampere-hours (Ah), capable of being
provided by a battery during discharge, the conditions of discharge being specified.
L. Battery Energy (Eb): The energy, in watt-hours (Wh), deliverable by the battery under known
discharge conditions. For the purposes of this specification and test methodology, the battery
energy shall be measured at a constant current discharge rate of 0.2 C. The test shall begin with a
fully charged battery, which is then discharged until the battery reaches its manufacturer specified
cutoff voltage. The battery energy is determined by measuring and integrating the battery voltage
over the course of discharge and multiplying by the constant current load. This value shall be
reported by the manufacturer and is subject to verification by EPA.
1 This definition is consistent with IEC 62301: Household Electrical Appliances - Measurement of Standby Power.
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M. Nameplate Input Power: The nameplate input power is either 1) the input power marked on the
nameplate (watts), or 2) where only nameplate input voltage and current ranges are provided, the
highest value achieved by multiplying a nameplate input voltage limit and its corresponding
current limit (Volt-Amperes).
N. Nominal Battery Voltage (Vb): Industry standard cell voltage multiplied by the number of cells in
the battery pack, normally listed on battery packaging. As of the writing of this battery charging
systems specification, industry accepted nominal cell voltages for applicable chemistries include:
1.2 volts for Nickel Cadmium and Nickel Metal Hydride; 2.0 volts for sealed lead acid; and 2.5-4.2
volts for Lithium Ion (depending on material used for the positive electrode and other factors).
O. Nonactive Energy Ratio (ER): The ratio of the accumulated nonactive energy (Ea) divided by the
battery energy (Eb). ER = Ea / Eb.
2) Qualifying Products: This ENERGY STAR specification applies to:
a) Battery charging systems packaged with portable, rechargeable products whose principal
output is mechanical motion, light, the movement of air, or the production of heat (e.g.,
small home appliances, personal care products, power tools, flashlights, and floor care
products);
b) Stand-alone battery chargers sold with products that use a detachable battery (e.g., some
digital camera and camcorder designs); and
c) Battery charging systems intended to replace standard sized primary alkaline cells
including: AAA, AA, C, D, 9-volt, etc. (i.e., universal battery chargers).
In addition, battery charging systems must meet the following conditions:
1. Chargers must be intended for rechargeable battery chemistries (e.g., Nickel Cadmium,
Lead Acid, Lithium Ion, and Nickel Metal Hydride) and not for primary cell chemistries
(e.g., alkaline "dry" cells);
2. Chargers may not rely on an inductive coupling system used to transfer energy between
two separate enclosures;
3. Batteries must have voltages less than 42 volts;
4. Chargers must have nameplate input power between 2 and 300 watts;
5. Chargers may not have a secondary functionality that draws power while the battery is
being charged/maintained (e.g., radio, cleaning machine, etc.) and is not related to
charging, maintaining, or monitoring a battery. These systems may, however, draw power
to provide a simple clock function and/or state of charge indicator. This exclusion does not
apply to 1) battery charging systems that provide power from the mains to operate
cord/cordless products or appliances with a discharged battery, and 2) products
containing additional functions that do not draw additional power;
6. All products must meet the ENERGY STAR requirements as packaged for sale. A la carte
chargers, which also may be multi-voltage and/or multi-port, may qualify as ENERGY
STAR if they meet the requirements when tested using at least three currently produced
batteries identified/listed as usable with the unit, as required in the ENERGY STAR Test
Methodology.2 If the same a la carte battery charger model also is packaged for sale with
end-use products using batteries, these systems may only qualify if the specific charger
and battery combinations also meet the ENERGY STAR requirements; and
7. Multi-port chargers may qualify if they meet the ENERGY STAR requirements when
tested with multiple identical batteries as outlined in the ENERGY STAR Test
Methodology. Similarly, multi-voltage chargers may qualify if they meet the ENERGY
STAR requirements with all applicable batteries of differing voltages as outlined in the
ENERGY STAR Test Methodology.
The following types of battery charging systems are not covered by this ENERGY STAR specification:
1. Inductively coupled devices used to transfer energy between two separate enclosures;
2. Chargers with nameplate input power less than 2 watts and greater than 300 watts; and
3. Charging systems that draw additional power to support added functionality such as
radios, CD players, GFI AC outlets, and cleaning devices.
2 See Section 4 for "Test Method for Determining the Energy Performance of Battery Charging Systems (Final, December 2005)."
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In order to qualify as ENERGY STAR, a model must meet the above parameters and the energy
performance criteria provided in Section 3, below.
Please note that single voltage external power supplies (including some that use the power supply's
dc output to charge batteries) and the end-use products they power are covered under separate
ENERGY STAR agreements ("ENERGY STAR Program Requirements for Single Voltage External
Ac-Dc and Ac-Ac Power Supplies" and "ENERGY STAR Program Requirements for End-Use Products
Using External Power Supplies"). Visit www.enerqvstar.gov/powersupplies for additional information.
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 4.5, consistent with the requirements for the next
highest voltage of 14.4 volts, to qualify as ENERGY STAR.)
Table 1: Energy Performance Criteria for Common Battery Voltages
Vb
1.2
2.4
3.6
4.8
6.0
7.2
8.4
9.6
10.8
12.0
ER
20.0
16.9
13.7
11.6
9.6
7.5
7.0
6.5
6.1
5.6
Vb
13.2
14.4
15.6
16.8
18.0
19.2
20.4
21.6
22.8
>24.0
ER
5.1
4.5
4.3
4.2
3.8
3.6
3.5
3.3
3.2
3.0
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. For chargers that charge individual cells in batches, 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 the arithmetic mean of all of the batch voltages tested. Please refer to the ENERGY
STAR Test Methodology for additional details.
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 (Final, December 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.
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.
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B. 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).
C. 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
Europe/Australia/New
230 volts ac, 50 Hz
Zealand:
Japan:
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).
D. 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.
5) Effective Date: The date that manufacturers may begin to qualify and promote battery charging
systems as ENERGY STAR will be defined as the effective date of the agreement. The ENERGY
STAR battery charging systems effective date is January 1, 2006.
6) Future Specification Revisions: EPA reserves the right to change the specification should
technological and/or market changes affect its usefulness to consumers, industry, or the
environment. In keeping with current policy, revisions to the specification are arrived at through
stakeholder discussions. In the event of a specification revision, please note that ENERGY STAR
qualification is not automatically granted for the life of a product model. To qualify as ENERGY
STAR, a product model must meet the ENERGY STAR specification in effect on the model's date of
manufacture. The date of manufacture is specific to each unit and is the date on which a unit is
considered to be completely assembled.
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