5C-i 

APPENDIX 5C. MANUFACTURER INTERVIEW GUIDE 

TABLE OF CONTENTS 

APPENDIX 5C. MANUFACTURER INTERVIEW GUIDE.............................................................. 5C-i

5C.1 INTRODUCTION .............................................................................................................. 5C-1

5C.2 EPS ENGINEERING ANALYSIS INTERVIEW GUIDE ................................................ 5C-1

5C.3 BC ENGINEERING ANALYSIS INTERVIEW GUIDE ................................................. 5C-8

LIST OF TABLES 

TABLE 5C.1 CHARACTERISTICS OF EXTERNAL POWER SUPPLY REPRESENTATIVE UNITS

............................................................................................................................................................... 5C-2

TABLE 5C.2 CANDIDATE STANDARD LEVELS OF EFFICIENCY FOR REPRESENTATIVE 

UNIT EPSS ........................................................................................................................................... 5C-2

TABLE 5C.3 EPS REP. UNIT 1 .......................................................................................................... 5C-4

TABLE 5C.4 EPS REP. UNIT 2 .......................................................................................................... 5C-5

TABLE 5C.5 EPS REP. UNIT 3 .......................................................................................................... 5C-6

TABLE 5C.6 EPS REP. UNIT 4 .......................................................................................................... 5C-7

TABLE 5C.7 CHARACTERISTICS OF BATTERY CHARGER REPRESENTATIVE UNITS ...... 5C-9

TABLE 5C.8 EFFICIENCY LEVELS OF EFFICIENCY FOR BATTERY CHARGER 

REPRESENTATIVE UNITS ............................................................................................................. 5C-10

TABLE 5C.9 DAILY USAGE ASSUMPTIONS FOR EACH REPRESENTATIVE UNIT ............ 5C-11

TABLE 5C.10 BC REP. UNIT 1 ........................................................................................................ 5C-13

TABLE 5C.11 BC REP. UNIT 2 ........................................................................................................ 5C-14

TABLE 5C.12 BC REP. UNIT 4 ........................................................................................................ 5C-15

TABLE 5C.13 BC REP. UNIT 5 ........................................................................................................ 5C-16

TABLE 5C.14 BC REP. UNIT 7 ........................................................................................................ 5C-17

TABLE 5C.15 BC REP. UNIT 10 ...................................................................................................... 5C-18

EERE-2008-BT-STD-0005 COMMENT 31
5C-1 

5C.1 INTRODUCTION 

 Prior to conducting manufacturer interviews, Navigant Consulting gave each manufacturer an 

interview guide that included possible questions to be asked during the interview. Section 5C.1 presents 

the guide used for EPS interviews and section 5C.3 presents the guide used for battery charger 

interviews. 

5C.2 EPS ENGINEERING ANALYSIS INTERVIEW GUIDE 

Engineering Analysis

On behalf of DOE, NCI is developing an engineering analysis to understand the relationship between 

manufacturers’ cost and the efficiency1 of external power supplies (EPSs). DOE would like to 

understand the incremental costs of reducing EPS energy consumption by understanding the design 

options involved in efficiency improvements. This section includes questions addressing this 

engineering analysis. 

1. What are the highest volume products that you sell? Please include output voltage, output 

power, and application. 

2. Please provide a list of any additional applications for which you sell EPSs or EPS components. 

3. Are there any specific design concerns unique to certain applications? 

4. What are the typical mark ups from the EPS bill of materials (BOM) to the final consumer 

purchase price? 

5. The U.S. Department of Energy (DOE) is required to set no-load and active mode energy 

efficiency standards for external power supplies. Is there a correlation between no-load power 

and active mode power efficiency? If not, can the two be optimized separately? 

6. What are your design options (e.g. Schottky diodes, improved components, better core material) 

for improving active mode efficiencies and no-load power consumption? 

We have identified four “representative units” (Table 1) as high volume units for our analysis. For each 

representative unit, DOE intends to establish a unit with baseline efficiency (EISA 2007) and three units 

with higher efficiency levels (ENERGY STAR 2.0, Best in Market, Maximum Technologically 

Feasible). 

 

1

“Efficiency” is used in this worksheet as a proxy for both conversion efficiency and no-load power. 

EERE-2008-BT-STD-0005 COMMENT 31
5C-2 

 

Table 5C.1 Characteristics of External Power Supply Representative Units 

Rep.

Unit

Output 

Power

[watts]

Output 

Voltage

[volts]

Annual Production 

Volume 

(Units / Year)

Example

Applications

1 2.5 5 1,000,000 Mobile Phone, Cordless Phone

2 18 12 1,000,000 Modem, Portable DVD player 

3 60 15 2,000,000 Laptop Computer, MP3 Speaker Dock

4 120 19 1,000,000 Laptop Computer

We identified pairings of no-load power and efficiency in the market that would meet the first three 

efficiency levels provided in Table 2. For each representative unit, presented in Tables 3-6, describe the 

discrete design steps you would undertake to achieve the level of average efficiency and no-load mode 

power consumption specified. If you cannot provide information on the exact pairings specified, please 

provide the characteristics (e.g. output power, output voltage, and applications) for models for which 

you can provide information. 

In each case, start with a power supply with baseline efficiency (CSL #0) that narrowly meets Federal 

efficiency requirements specified by the Energy Independence and Security Act of 2007 (EISA 2007). 

Next, please list the necessary design changes to enable it to meet the higher efficiency levels. For each 

design change, also provide an estimate of your incremental production cost over the baseline, as well as 

the total unit selling price to an OEM or distributor. Please describe how you apply markups to your 

production costs in order to arrive at that selling price. 

For CSL #3, please provide necessary steps to design a maximum technologically feasible (“max tech”) 

efficient power supply, using the best available technology, regardless of cost. Please describe the 

discrete design steps as well as the incremental production cost over the baseline. Please also provide the 

total unit selling price to an OEM or distributor. 

Table 5C.2 Candidate Standard Levels of Efficiency for Representative Unit EPSs 

Candidate Standard Level Efficiency Requirements by Representative Unit

CSL

# Description

2.5 watt 18 watt 60 watt 120 watt

Eff 

[%]

Pno_load

[mW]

Eff 

[%]

Pno_load

[mW]

Eff 

[%]

Pno_load

[mW]

Eff 

[%]

Pno_load

[mW]

0 EISA 2007 58% 500 76% 500 85% 500 85% 500

1

ENERGY STAR

2.0 63% 300 80% 300 87% 500 87% 500

2 Best in Market 65% 150 85% 100 88% 73 89% 340

3

Maximum 

Technologically 

Feasible

- - - - - - - -

EERE-2008-BT-STD-0005 COMMENT 31
5C-3 

We recognize that detailed designs may be difficult to prepare; therefore, in the interests of generating 

reasonable results in a short space of time, we invite you to use your best judgment and experience when 

completing the following tables. 

Please use the following design specifications: 

EXTERNAL POWER SUPPLY

Input voltage: 90-240 volts AC, 

50-60 Hz Transient response: 0.5 ms for 50% load change typical

Input protection: Primary current fuse, 

inrush current limiting Output protection: Overcurrent protection, short-circuit protection

Output voltage 

regulation: ± 1% (excluding cord) Package: Sealed polycarbonate

Output voltage ripple: 2-3% VP-P maximum Output Cord 

Length: 1.66 m

Indicator light: No indicator light

EERE-2008-BT-STD-0005 COMMENT 31
5C-4 

Table 5C.3 EPS Rep. Unit 1 

Rep.

Unit

Output 

Power

[watts]

Output 

Voltage

[volts]

Annual Production 

Volume 

(Units / Year)

Example

Applications

1 2.5 5 1,000,000 Mobile Phone, Cordless Phone

#

Efficiency 

Level

Conversion 

Efficiency2

NoLoad 

Power

Defining Design 

Characteristics

Mfr. 

Production 

Cost

Total Mfr. 

Production 

Cost

0

Baseline:

EISA 2007 58% 500 mW

#

Efficiency 

Level

Conversion 

Efficiency

NoLoad 

Power

Improvements 

over Baseline to 

Meet Efficiency 

Level

Incremental 

Cost (over 

Baseline) per 

Improvement

Total Mfr. 

Production 

Cost

1

ENERGY 

STAR 2.0

63% 300 mW

2

Best in Market 65% 150 mW

3

Maximum 

Technologically 

Feasible

 

2

 Conversion efficiency, as defined by DOE, ENERGY STAR, and CEC test procedures, is the arithmetic mean of 

efficiencies at 100%, 75%, 50%, and 25% of maximum rated output current. 

EERE-2008-BT-STD-0005 COMMENT 31
5C-5 

Table 5C.4 EPS Rep. Unit 2 

Rep.

Unit

Output 

Power

[watts]

Output 

Voltage

[volts]

Annual Production 

Volume 

(Units / Year)

Example

Applications

2 18 12 1,000,000 Modem, Portable DVD player 

#

Efficiency 

Level

Conversion 

Efficiency3

NoLoad 

Power

Defining Design 

Characteristics

Mfr. 

Production 

Cost

Total Mfr. 

Production 

Cost

0

Baseline:

EISA 2007 76 % 500 mW

#

Efficiency 

Level

Conversion 

Efficiency

NoLoad 

Power

Improvements 

over Baseline to 

Meet Efficiency 

Level

Incremental 

Cost (over 

Baseline) per 

Improvement

Total Mfr. 

Production 

Cost

1

ENERGY 

STAR 2.0

80% 300 mW

2

Best in Market 85% 100 mW

3

Maximum 

Technologically 

Feasible

 

3

 Conversion efficiency, as defined by DOE, ENERGY STAR, and CEC test procedures, is the arithmetic mean of 

efficiencies at 100%, 75%, 50%, and 25% of maximum rated output current. 

EERE-2008-BT-STD-0005 COMMENT 31
5C-6 

Table 5C.5 EPS Rep. Unit 3 

Rep.

Unit

Output 

Power

[watts]

Output 

Voltage

[volts]

Annual Production 

Volume 

(Units / Year)

Example

Applications

3 60 15 2,000,000 Laptop Computer, MP3 Speaker Dock

#

Efficiency 

Level

Conversion 

Efficiency4

NoLoad 

Power

Defining Design 

Characteristics

Mfr. 

Production 

Cost

Total Mfr. 

Production 

Cost

0

Baseline:

EISA 2007 85% 500 mW

#

Efficiency 

Level

Conversion 

Efficiency

NoLoad 

Power

Improvements 

over Baseline to 

Meet Efficiency 

Level

Incremental 

Cost (over 

Baseline) per 

Improvement

Total Mfr. 

Production 

Cost

1

ENERGY 

STAR 2.0

87% 500 mW

2

Best in Market 88% 73 mW

3

Maximum 

Technologically 

Feasible

 

4

 Conversion efficiency, as defined by DOE, ENERGY STAR, and CEC test procedures, is the arithmetic mean of 

efficiencies at 100%, 75%, 50%, and 25% of maximum rated output current. 

EERE-2008-BT-STD-0005 COMMENT 31
5C-7 

Table 5C.6 EPS Rep. Unit 4 

Rep.

Unit

Output 

Power

[watts]

Output 

Voltage

[volts]

Annual Production 

Volume 

(Units / Year)

Example

Applications

4 120 19 1,000,000 Laptop Computer

#

Efficiency 

Level

Conversion 

Efficiency5

NoLoad 

Power

Defining Design 

Characteristics

Mfr. 

Production 

Cost

Total Mfr. 

Production 

Cost

0

Baseline:

EISA 2007 85% 500 mW

#

Efficiency 

Level

Conversion 

Efficiency

NoLoad 

Power

Improvements 

over Baseline to 

Meet Efficiency 

Level

Incremental 

Cost (over 

Baseline) per 

Improvement

Total Mfr. 

Production 

Cost

1

ENERGY 

STAR 2.0

87% 500 mW

2

Best in Market 89% 340 mW

3

Maximum 

Technologically 

Feasible

 

5

 Conversion efficiency, as defined by DOE, ENERGY STAR, and CEC test procedures, is the arithmetic mean of 

efficiencies at 100%, 75%, 50%, and 25% of maximum rated output current. 

EERE-2008-BT-STD-0005 COMMENT 31
5C-8 

5C.3 BC ENGINEERING ANALYSIS INTERVIEW GUIDE 

Engineering Analysis

On behalf of the U.S. Department of Energy (DOE), Navigant Consulting is developing an engineering 

analysis to understand the relationship between manufacturers’ cost and the energy consumption of 

battery chargers (BCs). DOE would like to understand the incremental costs of reducing BC energy 

consumption by understanding the design options involved in efficiency improvements. This section 

includes questions addressing this engineering analysis. 

1. Please provide a list of BC end-use product applications which you sell or for which you sell 

components. 

2. Please provide estimates of the typical consumer usage patterns of those end-use products, if 

available. 

3. What are the highest volume products that you sell? Please include output voltage, output 

power, and application. 

4. What are the typical mark ups from the BC bill of materials (BOM) to the final consumer 

purchase price? 

5. How should DOE approach BCs for applications that provide additional functionality that is 

typically never turned off, thereby increasing apparent BC energy consumption, e.g., cordless 

telephone answering machines? 

6. How can DOE extrapolate from the analysis of BCs for high-volume consumer applications such 

as notebook computers, power tools, and cordless telephones to specialized, lower-volume 

applications such as: 

o Inductively-charged toothbrushes; 

o Uninterruptible power supplies; 

o DC-input products such as portable media players or in-car satellite navigation systems? 

7. Are there any other BC design concerns unique to certain applications? 

8. What are your design options (e.g. Schottky diodes, improved components, maintenance 

strategies) for improving BC energy consumption in: 

o Active or charge mode; 

o Maintenance mode; and 

o No-battery or standby mode? 

9. Also, what is the available range of performance in each of the above modes for BCs with which 

you have experience? 

10. What is the relationship between BC energy consumption in the above modes? 

EERE-2008-BT-STD-0005 COMMENT 31
5C-9 

11. Since it is impossible to directly evaluate every potential BC, how should DOE model the impact 

of small variations in battery voltage and capacity on the efficiency of a particular BC design? 

12. How would your approach to decreasing the energy consumption of BCs change if presented 

with: 

o A single standard specifying annual energy consumption given a typical usage; versus 

o Separate standards specifying input power or energy consumption in each mode? 

Because of the wide variety of applications that use battery chargers, DOE has decided to focus its 

analysis on several “representative units” as high volume units for its analysis. The typical battery 

characteristics and production volume of each representative unit are presented in Table 1. 

Table 5C.7 Characteristics of Battery Charger Representative Units 

Rep. 

Unit #

Product 

Class

Battery 

Voltage

V

Battery 

Energy

Wh

Annual 

Production 

Volume

K units

Lifespan

Production

Volume

K units Typical Applications

1

Low Energy, 

Inductive 1.2 0.8 1,000 2,000 Toothbrushes

2

Low Energy, 

Low Voltage 3.6 3 1,000 2,000 Telephones

3

Low Energy, 

Med. Voltage Not gathering data at this time

4

Low Energy, 

High Voltage 10.8 20 1,000 2,000 Notebook Computers, Power Tools

5

Med. Energy, 

Low Voltage 12 800 10 50 Marine Chargers, Wheelchairs

6

Med. Energy, 

High Voltage Not gathering data at this time

7 High Energy 48 3750 10 50 Golf Carts

8

Low Energy, 

5V DC Input Not gathering data at this time

9

Low Energy, 

12V DC Input Not gathering data at this time

10 Low Energy, 

AC Output 12 70 100 500 Uninterruptible Power Supplies

For each representative unit, DOE intends to evaluate the impacts of standards equal to the efficiency of 

baseline units and three additional units (where available) with higher efficiency levels: 

o Intermediate, 

o Best-in-Market, and 

o Maximum Technologically Feasible. 

Navigant Consulting based the Baseline, Improved, and Best-in-Market levels on BC products currently 

available in the market. There are no products with the Maximum Technologically Feasible efficiency in 

EERE-2008-BT-STD-0005 COMMENT 31
5C-10

the market. For BCs at each of these efficiency levels, we measured the energy consumption in active, 

maintenance, and no-battery modes, and then calculated the energy consumption based on the typical 

usage of common applications that use batteries charged by these BCs. This information is listed in 

Table 2. 

Table 5C.8 Efficiency Levels of Efficiency for Battery Charger Representative Units 

Annual Energy Consumption by Representative Unit 

kWh

Low 

Energy, 

Inductive

Low 

Energy, 

Low 

Voltage

Low 

Energy, 

High 

Voltage

Med. 

Energy, 

Low 

Voltage

High 

Energy

Low 

Energy, 

AC 

Output

# Efficiency Level

1.2 V, 

0.8 Wh 

3.6 V, 

3 Wh

10.8 V, 

20 Wh

12 V, 

800 Wh

48 V,

3750 Wh

12 V, 

70 Wh

0 Baseline 7.8 15.2 39.0 292.9 – 65.0

1 Improved – 6.3 10.7 – 912.7 19.5

2 Best-in-Market 5.9 1.5 3.6 210.0 – 6.4

3

Maximum 

Technologically 

Feasible

? ? ? ? ? ?

For each representative unit, presented in Tables 4–6 on the following pages, please describe the discrete 

design steps you would undertake to achieve the level of energy consumption specified. The test data for 

the BCs that Navigant Consulting tested is also presented as an example of an acceptable design; 

however, please do not hesitate to trade off performance in one mode against that in another when 

attempting to meet the annual energy consumption specified for each CSL. 

The energy consumption is calculated by multiplying the efficiency or input power in each mode by the 

number of hours per week spent in the mode. The resulting energy consumption is then annualized. 

Please use the equation below, when calculating annual energy consumption. Table 3 shows the usage 

assumptions for each representative unit. 

kWh

Wh 1000

yr

days 365.2 5

( ) ACTIVE BATT CHARGES MAINT MAINT N O _ BATT N O _ BATT OFF OFF E E E n P t P t P t

 

EERE-2008-BT-STD-0005 COMMENT 31
5C-11

Table 5C.9 Daily Usage Assumptions for Each Representative Unit 

Time Per Day Spent in Each Mode*

Representative Unit Classes 

and Example 

Applications

Charges 

[daily]

Active 

[hr/day]

Maintenance 

[hr/day]

NoBattery 

[hr/day]

Off 

[hr/day]

Unplugged 

[hr/day]

Total

[hr/day]

Low Energy, Inductive 0.01 0.2 23.7 0.02 - - 24

Toothbrushes 0.2 23.7 0.02 - - 24

Low Energy, Low Voltage 0.8 2.7 11.2 1.4 - 8.7 24

Phones/Answering 

Devices 8.4 13.49 2.2 - - 24

E-Books 0.8 5.2 - - 18.0 24

Mobile phones 0.7 7.2 4.6 - 11.5 24

MP3 Speaker Docks 0.9 22.9 0.3 - - 24

Portable Video Game 

Systems (PSP) 2.7 7.3 - - 14.0 24

Low Energy, High Voltage 0.2 1.0 16.5 3.0 0.2 3.3 24

Handheld Vacuums 0.9 22.9 0.3 - - 24

Trimmers/Weed 

Trimmers 0.5 11.5 3.1 - 8.9 24

Robotic Vacuums 0.9 22.9 0.3 - - 24

Stick Vacuums 0.9 22.9 0.3 - - 24

Handheld Printer 2.4 10.6 8.4 - 2.6 24

Notebook Computers 1.0 13.4 7.2 - 2.4 24

Professional Power 

Tools 0.5 11.5 1.6 1.6 8.9 24

Med Energy, Low Voltage 0.5 4.4 8.5 7.0 2.8 1.3 24

Electric Wheelchairs/ 

Scooters 8.6 6.7 8.4 - 0.2 24

Marine Battery Charger 0.2 10.2 5.6 5.6 2.4 24

High Energy 1.6 13.9 3.1 2.8 2.8 1.4 24

Golf Carts 13.9 3.1 2.8 2.8 1.4 24

Low Energy, AC Output - - 24.0 - - - 24

Uninterruptible Power 

Supplies - 24.0 - - - 24

*Mode Definitions

Active: The charger is charging a depleted battery, equalizing it cells, or performing functions necessary for bringing the 

battery to the fully charged state. 

Maintenance: The batteries have reached full charge; intended to maintain the fully charged state of the battery, while 

protecting it from overcharge. 

No-Battery: The battery is removed from the charger following a full charge. The charger (or a part) remains connected to 

mains. 

Off: The charger remains connected to mains, the battery is removed, and all manual on-off switches are turned off. 

Unplugged: The charger is disconnected from mains entirely. 

EERE-2008-BT-STD-0005 COMMENT 31
5C-12

Please only focus on the representative units with which your company has experience, since not all may 

be applicable. In each case, start with a BC with baseline energy consumption, comparable to that 

presented and representing the least efficient BCs in the market. Next, please list the necessary design 

changes to enable it to meet the higher efficiency levels. For each design change, also provide an 

estimate of incremental production cost over the baseline, as well as the total unit selling price to a 

mass-market retailer or distributor. Please describe how you apply markups to your production costs in 

order to arrive at each selling price. 

For the maximum technologically feasible (“max-tech”) level, please provide necessary steps to design a 

BC with the minimum possible energy consumption, using the best available technology and regardless 

of cost. Please describe the discrete design steps as well as the incremental production cost over the 

baseline. Please also provide the total unit selling price to a mass-market retailer or distributor. 

We recognize that detailed designs may be difficult to prepare; therefore, in the interests of generating 

reasonable results in a short span of time, we invite you to use your best judgment and experience when 

completing the following tables. 

EERE-2008-BT-STD-0005 COMMENT 31
5H-13

Table 5C.10 BC Rep. Unit 1 

Rep. 

Unit 

# Product Class

Battery 

Voltage

V

Battery 

Energy

Wh

Annual Production 

Volume

K units

Lifespan Production

Volume

K units

Typical 

Applications

1

Low Energy, 

Inductive 1.2 0.8 1,000 2,000 Toothbrushes

#

Efficiency 

Level

Annual 

Energy 

Consumption

kWh

Example 

Active-Only 

Efficiency6

%

Example 

Maint. 

Mode Power 

W

Example NoBattery 

Mode Power

W

Defining Design 

Characteristics

Mfr. Production 

Cost

Total 

Mfr.

Prod. 

Cost

0 Baseline 7.8 8% 0.9 0.6

#

Efficiency 

Level

Annual 

Energy 

Consumption

kWh

Example 

Active-Only 

Efficiency

%

Example 

Maint. 

Mode Power 

W

Example NoBattery 

Mode Power

W

Improvements 

over Baseline to 

Meet Efficiency 

Level

Incremental Cost 

(over Baseline) 

per Improvement

Total 

Mfr.

Prod. 

Cost

1 Improved

2

Best-inMarket 5.9 8% 0.7 0.5

3

Max-Tech

 

6

 Combines the efficiency of the power conversion circuitry and the battery. Defined as the energy recovered from the battery during a 0.2 C discharge, divided 

by the energy consumed by the charger during active mode. 

EERE-2008-BT-STD-0005 COMMENT 31
5H-14

Table 5C.11 BC Rep. Unit 2 

Rep. 

Unit 

# Product Class

Battery 

Voltage

V

Battery 

Energy

Wh

Annual Production 

Volume

K units

Lifespan Production

Volume

K units

Typical 

Applications

2

Low Energy, 

Low Voltage 3.6 3 1,000 2,000 Telephones

#

Efficiency 

Level

Annual 

Energy 

Consumption

kWh

Example 

Active-Only 

Efficiency7

%

Example 

Maint. 

Mode Power 

W

Example 

No-Battery 

Mode Power

W

Defining Design 

Characteristics

Mfr. Production 

Cost

Total 

Mfr.

Prod. 

Cost

0 Baseline 15.2 6% 2.04 1.281

#

Efficiency 

Level

Annual 

Energy 

Consumption

kWh

Example 

Active-Only 

Efficiency

%

Example 

Maint. 

Mode Power 

W

Example 

No-Battery 

Mode Power

W

Improvements 

over Baseline to 

Meet Efficiency 

Level

Incremental Cost 

(over Baseline) 

per 

Improvement

Total 

Mfr.

Prod. 

Cost

1 Improved 6.3 54% 1.38 0.110

2

Best-inMarket

1.5 45% 0.12 0.056

3

Max-Tech

 

7

 Combines the efficiency of the power conversion circuitry and the battery. Defined as the energy recovered from the battery during a 0.2 C discharge, divided 

by the energy consumed by the charger during active mode. 

EERE-2008-BT-STD-0005 COMMENT 31
5H-15

Table 5C.12 BC Rep. Unit 4 

Rep. 

Unit 

# Product Class

Battery 

Voltage

V

Battery 

Energy

Wh

Annual Production 

Volume

K units

Lifespan Production

Volume

K units Typical Applications

4

Low Energy,

High Voltage 10.8 20 1,000 2,000 Notebook Computers, Power Tools

 

8

 Combines the efficiency of the power conversion circuitry and the battery. Defined as the energy recovered from the battery during a 0.2 C discharge, divided 

by the energy consumed by the charger during active mode. 

#

Efficiency 

Level

Annual 

Energy 

Consumption

kWh

Example 

Active-Only 

Efficiency8

%

Example 

Maint. Mode 

Power 

W

Example 

No-Battery 

Mode Power

W

Defining Design 

Characteristics

Mfr. Production 

Cost

Total 

Mfr.

Prod. 

Cost

0 Baseline 39.0 56% 5.9 2.2

#

Efficiency 

Level

Annual 

Energy 

Consumption

kWh

Example 

Active-Only 

Efficiency

%

Example 

Maint. Mode 

Power 

W

Example 

No-Battery 

Mode Power

W

Improvements 

over Baseline to 

Meet Efficiency 

Level

Incremental 

Cost (over 

Baseline) per 

Improvement

Total 

Mfr.

Prod. 

Cost

1 Improved 10.7 69% 1.4 1.4

2

Best-inMarket 4.2 70% 0.6 0.1

3

Max-Tech

EERE-2008-BT-STD-0005 COMMENT 31
5H-16

Table 5C.13 BC Rep. Unit 5 

Rep. 

Unit 

# Product Class

Battery 

Voltage

V

Battery 

Energy

Wh

Annual Production 

Volume

K units

Lifespan Production

Volume

K units

Typical 

Applications

5

Med. Energy, Low 

Voltage 12 800 10 50 Marine Chargers, Wheelchairs

 

9

 Combines the efficiency of the power conversion circuitry and the battery. Defined as the energy recovered from the battery during a 0.2 C discharge, divided 

by the energy consumed by the charger during active mode. 

#

Efficiency 

Level

Annual 

Energy 

Consumption

kWh

Example 

Active-Only 

Efficiency9

%

Example 

Maint. Mode 

Power 

W

Example 

No-Battery 

Mode Power

W

Defining Design 

Characteristics

Mfr. Production 

Cost

Total 

Mfr.

Prod. 

Cost

0 Baseline 293.5 46% 21.2 20.1

#

Efficiency 

Level

Annual 

Energy 

Consumption

kWh

Example 

Active-Only 

Efficiency

%

Example 

Maint. Mode 

Power 

W

Example 

No-Battery 

Mode Power

W

Improvements 

over Baseline to 

Meet Efficiency 

Level

Incremental Cost 

(over Baseline) 

per 

Improvement

Total 

Mfr.

Prod. 

Cost

1 Improved

2

Best-inMarket 210.4 49% 11.9 11.6

3

Max-Tech

EERE-2008-BT-STD-0005 COMMENT 31
5H-17

Table 5C.14 BC Rep. Unit 7 

Rep. 

Unit 

# Product Class

Battery 

Voltage

V

Battery 

Energy

Wh

Annual Production 

Volume

K units

Lifespan Production

Volume

K units

Typical 

Applications

7 High Energy 48 3750 10 50 Golf Carts

#

Efficiency 

Level

Annual 

Energy 

Consumption

kWh

Example 

Active-Only 

Efficiency10

%

Example 

Maint. 

Mode Power 

W

Example NoBattery 

Mode Power

W

Defining Design 

Characteristics

Mfr. Production 

Cost

Total 

Mfr.

Prod. 

Cost

0 Baseline

#

Efficiency 

Level

Annual 

Energy 

Consumption

kWh

Example 

Active-Only 

Efficiency

%

Example 

Maint. 

Mode Power 

W

Example NoBattery 

Mode Power

W

Improvements 

over Baseline to 

Meet Efficiency 

Level

Incremental Cost 

(over Baseline)

per Improvement

Total 

Mfr.

Prod. 

Cost

1 Improved 912.7 71% 3.3 1.5

2

Best-inMarket

3

Max-Tech

 

10 Combines the efficiency of the power conversion circuitry and the battery. Defined as the energy recovered from the battery during a 0.2 C discharge, divided 

by the energy consumed by the charger during active mode. 

EERE-2008-BT-STD-0005 COMMENT 31
5H-18

Table 5C.15 BC Rep. Unit 10 

Rep. 

Unit 

# Product Class

Battery 

Voltage

V

Battery 

Energy

Wh

Annual Production 

Volume

K units

Lifespan Production

Volume

K units

Typical 

Applications

10 Low Energy, AC 

Output 12 70 100 500 Uninterruptible Power Supplies

 

11 Combines the efficiency of the power conversion circuitry and the battery. Defined as the energy recovered from the battery during a 0.2 C discharge, divided 

by the energy consumed by the charger during active mode 

#

Efficiency 

Level

Annual 

Energy 

Consumption

kWh

Example 

Active-Only 

Efficiency11

%

Example 

Maint. 

Mode Power 

W

Example 

No-Battery 

Mode Power

W

Defining Design 

Characteristics

Mfr. Production 

Cost

Total 

Mfr.

Prod. 

Cost

0 Baseline 65.0 28% 7.4 N/A

#

Efficiency 

Level

Annual

Energy 

Consumption

kWh

Example 

Active-Only 

Efficiency

%

Example 

Maint. 

Mode Power 

W

Example 

No-Battery 

Mode Power

W

Improvements 

over Baseline to 

Meet Efficiency 

Level

Incremental Cost 

(over Baseline) 

per Improvement

Total 

Mfr.

Prod. 

Cost

1 Improved 19.5 52% 2.2 N/A

2

Best-inMarket 6.4 59% 0.7 N/A

3

Max-Tech

EERE-2008-BT-STD-0005 COMMENT 31