NSMRL TECHNICAL REPORT #1220 26 JUNE 2001

FEASIBILITY OF USING COMMERCIAL-OFF-THE-SHELF

RUGGEDIZED LAPTOP COMPUTERS AND INDEPENDENT

POWER SOURCES IN A DISABLED SUBMARINE

R. S. Kargher

S. J. Ryder

D. D. Wray

R D. Woolrich

W. G. Horn

Released by:

M. D. CURLEY, CAPT, MSC, USN

Commanding Officer

Naval Submarine Medical Research Laboratory

Approved for public release; distribution unlimited.
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1. REPORT DATE (DD-MM-YYYY)

26-06-08-02-20012001

2. REPORT TYPE

technical

3. DATES COVERED (From - To)

01-01-2001 to 26-06-2001

4. TITLE AND SUBTITLE

Feasibility of Using Commercial-Off-the-Shelf Ruggedized

Laptop Computers and Independent Power Sources in a Disabled

Submarine

5a. CONTRACT NUMBER

5b. GRANT NUMBER

5c. PROGRAM ELEMENT NUMBER

6. AUTHOR(S)

Kargher, R S; Author

Ryder, S J; Author

Wray, D D; Author

Woolrich, R D; Author

Horn, W G; Author

5d. PROJECT NUMBER

5e. TASK NUMBER

5f. WORK UNIT NUMBER

7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES)

Naval Submarine Medical

Research Laboratory

Naval Submarine Base New

London Box 90 0

Groton, CT 06349-5900

8. PERFORMING ORGANIZATION REPORT

NUMBER

1220

9. SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS(ES)

Naval Submarine Medical Resea

rch Laboratory

Naval Submarine Base New

Groton, CT 06349-5900

10. SPONSOR/MONITOR'S ACRONYM(S)

NSMRL

11. SPONSOR/MONITOR'S REPORT

NUMBER(S)

1220

12. DISTRIBUTION /AVAILABILITY STATEMENT

A Approved for public release; distribution is unlimited.

13. SUPPLEMENTARY NOTES

14. ABSTRACT

This project evaluated two commercial-offthe-shelf(COTS) laptop computer systems and two power supplies for

ruggedness and performance under conditions expected aboard a disabled submarine (DISSUB) for potential use with the

Submarine Escape and Rescue Expert (SEAREX) computer program. Computers and power supplies were tested in

hyperbaric chambers at Naval Submarine Medical Research Laboratory (NSMRL) under hyperbaric (5 bar), high humidity

(>80%) and low temperature (<45F) conditions simulating a DISSUB. One ofthe two laptop computer systems tested met

all requirements. The other failed due to the failure ofits keyboard. The lead-acid battery design tested supplied sufficient

power to energize a computer for nearly five days and the alkaline battery pack lasted for nearly seven days. This testing

demonstrated that COTS hardware capable ofsupporting SEAREX in a DISSUB is nearly available.

15. SUBJECT TERMS

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UNCLASSIFIED

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UNCLASSIFIED

c. THIS PAGE

UNCLASSIFIED

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OF ABSTRACT

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Unlimited

18. NUMBER

OF PAGES

54

19a. NAME OF RESPONSIBLE PERSON

Ronald Joe

19b. TELEPHONE NUMBER (include area

code)

860-694-5157
Standard Form 298 (Rev. 8-98)

Prescribed by ANSI Std. Z39.18
Feasibility Of Using Commercial-Off-The-Shelf

Ruggedized Laptop Computers And Independent

Power Sources In a Disabled Submarine

R. S. Kargher

S. J. Ryder

D. D. Wray

R. D. Woolrich

W. G. Horn

Naval Submarine Medical Research Laboratory

Report #1220

WR63713 N0463A99WR00015

Approved and Released by

M. D. Curley, CAPT, MSC, USN

Commanding Officer

NAVSUBMEDRSCHLAB

Approved for public release; distribution unlimited
Summary Page

Problem

The Submarine Escape and Rescue Expert System (SEAREX) is a computer program that

provides advice to the senior survivor and/or topside rescue personnel on how to optimize

the survival ofthe crew aboard a sunken/disabled submarine (DISSUB). To function at

all inside the DISSUB, the program requires a computer and power source capable of

performing for up to seven days in the hostile environment expected in a DISSUB (high

pressure, high humidity and low temperature). To be cost effective, the system should

use, where possible, commercial-off-the-shelf (COTS) components that are capable of

surviving the catastrophic event that disabled the submarine. This project determined

whether appropriate COTS computers and power sources were available and subjected

several candidate products to simulated DISSUB conditions to assess performance.

Methods

After establishing a set of environmental and operational parameters that reflect a

credible DISSUB scenario, the commercial market was searched for candidate computers

and power sources. Two ruggedized computers and two battery designs were identified

that appeared to meet the required specifications. Hyperbaric chambers were used to

simulate DISSUB conditions in which the performance and endurance ofthe candidate

equipment were tested.

Findings

Ofthe two computers tested during November 1999, one met the required performance

standard after modification. The membrane keyboard ofthe other computer, as

configured, was unusable in this simulated DISSUB scenario, although the electronics

appeared to function normally. Ofthe two battery power supplies tested, one was able to

power a ruggedized laptop for nearly five days and the other nearly seven. A promising

third battery power supply design, based on zinc-air technology and under development

for the U.S. Army, was considered, but was rejected due to cost.

Conclusion

A test of a small selection of COTS computers and batteries revealed that at least one

ruggedized COTS computer and power supply are capable ofsupporting SEAREX under

likely DISSUB conditions for nearly a week.

ADMINISTRATIVE INFORMATION

This investigation was conducted under Naval Sea Systems Command work unit #WR63713 N0463A99WR00015-5908,

entitled "Hardware Acquisition". The views expressed in this report are those of the authors and do not reflect the official

policy or position of the Department of the Navy, Department of Defense, or the U.S. Government. This report was

approved for publication on 26 June 2001, and designated as Naval Submarine Medical Research Laboratory

Report #1220.
Abstract

This project evaluated two commercial-off-the-shelf (COTS) laptop computer systems

and two power supplies for ruggedness and performance under conditions expected

aboard a disabled submarine (DISSUB) for potential use with the Submarine Escape and

Rescue Expert (SEAREX) computer program. Computers and power supplies were

tested in hyperbaric chambers at Naval Submarine Medical Research Laboratory

(NSMRL) under hyperbaric (5 bar), high humidity (>80%) and low temperature (<45°F)

conditions simulating a DISSUB. One ofthe two laptop computer systems tested met all

requirements. The other failed due to the failure of its keyboard. The lead-acid battery

design tested supplied sufficient power to energize a computer for nearly five days and

the alkaline battery pack lasted for nearly seven days. This testing demonstrated that

COTS hardware capable ofsupporting SEAREX in a DISSUB is nearly available.
Table of Contents

Summary Page i

Abstract ii

Table of Appendices iv

Table of Figures v

I Introduction 1

II Materials and Methods 3

A. Materials 3

B. Methods 9

III Results 17

A. Computer Test Results 17

1. Pre-Test 17

2. Main Test 17

a. Main-Test, Paravant 18

b. Main Test, Itronix 18

3. Power Consumption 19

B. Power Source Test Results 20

IV Discussion 21

V Conclusion 23

Acknowledgments 24

References 25

in
Table ofAppendices

Vendors' Environmental Specifications of

Each Candidate Laptop Appendix A

Submarine Escape And Rescue Expert System

Power Supply Selection Report Appendix B

SHOWTIME PROGRAM Appendix C

IV
Table ofFigures

Figure 1. Paravant RLT-515 5

Figure 2. Itronix X-C 6250 6

Figure 3. Sonnenschein Prevailer® 7

Figure 4. Mathew Associates Pack 8

Figure 5. View of ICE from The Hyperbaric

Chamber Inner Lock 10

Figure 6. Hyperbaric Medical Research Chamber,

F-017 N.B. #324 (Chamber #2) 11

Figure 7. View Taken From Hyperbaric Chamber

Viewing Port of ICE With Diver Under

Pressure Conducting Computer Testing

on the Paravant Computer 13

Figure 8. Hyperbaric Chamber, Prior to Testing 15

Figure 9. Hyperbaric Medical Research Chamber

F-017 N.B. #324 Under Pressure

During Battery Test 16

Figure 10. Power Source Test Circuit 17

Figure 11. Voltage of Each Power Source During

Discharge 20

Figure 12. Electric Fuel Corp. Zinc-Air Cell 22
I Introduction

Survival in a disabled submarine (DISSUB) that is unable to surface under its own power is a

problem that could be faced by U.S. Navy submariners. Although rescue is the preferred means

ofrecovering survivors1, hazards such as uncontrollable flooding, radiation, fires, and toxic gas

contamination ofthe atmosphere may make immediate escape necessary. However, escape is

also potentially hazardous. The hazards include decompression sickness, pulmonary barotrauma,

hypothermia, and drowning . The risk of decompression sickness increases with the depth ofthe

boat and the pressure within the DISSUB; flooding can pressurize the interior ofthe boat to

levels that make escape extremely dangerous1. The senior survivor needs to balance the risk of

remaining in the boat against that of escaping to the surface and, while waiting for rescue, to

optimize the use ofthe available men and materiel. While it is his responsibility to optimize the

survival of his crew, at present, his sources of information are scattered throughout various

publications1.

An obvious solution would be to consolidate this information and advice on DISSUB survival

into a single rugged workbook. The British Royal Navy has developed such a tool called the

'Guard Book'3. It is a collection of flow-charts, pencil-and-paper worksheets, and instructions

that guides the senior survivor on what he and his crew must do to maximize survival. In

October 1996, the Naval Submarine Medical Research Laboratory (NSMRL) was tasked by the

Chief ofNaval Operations, CNO N873, to develop a guide for the senior survivor of a US Navy

DISSUB similar to the British 'Guard Book.

Depending on the location ofthe DISSUB, it may take up to a week for rescue resources to

arrive at the scene. The problem ofmaximizing survival time while waiting for rescue has been

well recognized. A 'Guard Book' can greatly improve the survival time in the DISSUB through

the efficient use ofstores. However, pencil-and-paper technology limits the complexity ofthe

calculations that can be performed and does not relieve the senior survivor ofremembering to

undertake tasks with which he is likely to be unfamiliar. Providing more sophisticated and

readily understood advice requires computer technology.

SEAREX provides systematic instructions, offers an alarm clock function for important timecritical actions, and consolidates the necessary documentation in hypertext-linked (HTML) files.

It undertakes many calculations that are considerably more sophisticated than can be easily

achieved on paper. It provides the senior survivor and his topside support forces with a single,

reliable source of information to assess and manage the situation.

No decision aid will relieve the senior survivor of his responsibility for managing his men and

materiel, nor is this considered appropriate. It is possible to relieve him ofthe need to remember

to undertake tasks that are not normally required of him and to provide risk assessments in

circumstances that are beyond his experience. This is the ultimate purpose of SEAREX.

It is envisaged that the SEAREX computer and its power supply would be stowed in a protective

container near the escape trunk. It should require minimal maintenance and yet be ready for

operation at short notice. To be cost-effective, the system should consist of commercial-off-theshelf (COTS) components that are capable ofsurviving the catastrophic event that disabled the

submarine.

1
DISSUB conditions mandate a system that is —

1. Robust

2. Water-resistant, and tolerant of humidity up to 90% RH

3. Pressure tolerant, from 0.9 to 5 ATA

4. Cold tolerant, down to 32°F

5. Capable ofseven days continuous operation

6. Compact

7. Cost effective, employing COTS technology where possible

This project was undertaken to determine whether any appropriate COTS computers and power

sources were available on the open market to meet these specifications and, ifthey were, to

subject a few candidate products to simulated DISSUB conditions to assess the extent to which

they meet the manufacturers' claims.
II Materials and Methods

SEAREX software was designed to run under either the Microsoft® Windows® 95 or

Windows® NT 4.0 operating systems (OS). The minimum requirements, based on the needs of

the OS, and for adequate performance from SEAREX, are: a 60 MHz Intel® Pentium® central

processing unit (CPU), 8 megabytes(MB) ofrandom access memory (RAM), and 200 MB of

data storage. SEAREX occupies about 10 MB ofthis data storage; the balanced is required for

the OS to operate properly. Data storage is provided by Flash-RAM technology instead of a hard

drive, because of its lower power requirements and greater robustness.

From March through May of 1999, a list of potential computer candidates was compiled through

the Internet, various trade magazines and word-of-mouth. The first criterion for inclusion was

that the claimed range of environmental parameters of operation included the conditions

expected in a DISSUB. The second criterion was having among the highest resistance to water

and shock. Furthermore, the vendor had to state that these claims were tested in accordance with

military standard MIL-STD-810E (Appendix A). The third criterion was that the computer was

equipped with an appropriate color display. The SEAREX software requires a display capable of

showing 256 colors at a resolution of at least 800 x 600 pixels. For current laptop designs (in

1999), this implies a back-lit, color, liquid crystal display (LCD) screen which may require a

heater to function properly in very cold environments.

From our survey, a review ofmanufacturers' reported specifications indicated that suitable

hardware would require an estimated 10 to 15 watts of electrical power at 12 volts DC. Based on

that estimate of power usage and suitability for use in a DISSUB scenario, the Naval Surface

Warfare Center, Carderock Division, in West Bethesda, Maryland (NSWC) was contracted to

conduct a market survey of COTS power sources. Their report is in Appendix B.

Although NSWC's first recommendation was to use a zinc-air battery that is being developed for

the U.S. Army by Electric Fuel Corporation (EFC), a prototype zinc-air battery pack capable of

powering a laptop forjust 24 hours would have cost about $3000. We did not test this potential

power source due to its low probability of being adopted by the fleet due to cost. Nonetheless,

the technology has great potential for this application and should be revisited when in full

production. For this study, we opted for their second and third recommendations: alkaline and

lead-acid battery designs.

A. Materials

Two ruggedized laptop computers were provided under loan arrangement with each supplier for

the purpose oftesting. These were as follows:
1) Paravant RLT-515 (Figure 1)

a) OS: Microsoft® Windows® 95

b) CPU: 133 MHz Advanced Micro Devices AuthenticAMD

c) RAM: 8 MB

d) FlashRAM: SanDisk ATA 220 MB

e) Cost: Approximately $12,000

2) Itronix X-C 6250 (Figure 2)

a) OS: Microsoft® Windows® 95

b) CPU: 200 MHz Intel® Pentium®

c) RAM: 48 MB

d) FlashRAM: SanDisk ATA 220 MB

e) Cost: Approximately $5,500

The power sources tested were:

1) Sonnenschein Prevailer® Dryfit® PV-30H Marine Battery (Figure 3)

a) Technology: Gelled Lead Acid

b) Nominal Voltage: 12 V

c) Amp Hours: rated at 200 AH

d) Dimensions: 13x9x7 inches (33 x 23 x 18 cm)

e) Volume: 0.47 cu ft (13309 cc)

f) Weight: 80 lbs. (30 kg)

g) Cost: $150
£311 3MLJ ■■!' JÜÜ

*i^

mmfeHpMif.-SXttIn !.i"d1

Figure 1. Paravant RLT-515
Figure 2. Itronix X-C 6250
^J^^„ i /

; V

fA

Figure 3. Sonnenschein Prevailer® Dryfit® PV-3ÖH Marine Battery
V

i

Figure 4. Mathew Associates Custom Militarized Battery Pack
2) Mathew Associates Custom Militarized Battery Pack (Figure 4)

a) Technology: Alkaline

(168 standard D-cell alkaline batteries)

b) Nominal Voltage: 18 V

c) Amp Hours: estimated at 200 AH

d) Dimensions: a cylinder IVi diameter x 18 inches high (19 x 46 cm)

e) Volume: 0.46 cu ft (13026 cc)

f) Weight: 60 lbs. (22.4 kg)

g) Cost: $525

The Sonnenschein Marine Battery is a standard mass-produced gelled lead-acid battery. It was

tested unmodified.

The Mathew Associates Custom Militarized Battery Pack is constructed from standard massproduced D-size alkaline batteries. The batteries are arranged within a disc-shaped plastic

housing called a "puck." Each puck holds up to 24 D-size battery cells that can be connected in a

number of different ways. Each is filled with epoxy-based filler that seals in the batteries and

protects their electrical connections.

The pack used consisted ofseven pucks connected in parallel. Each puck contained two strings

of 12 cells connected in series. This gave a nominal output of 18 VDC.

B. Methods

The computers and the power sources were tested independently to avoid difficulty in

determining the cause ofsystem failures. For all tests, the power management features of each

laptop were fully disabled so that the display and CPU were always active and highest levels of

power consumption could be measured. While a computer pressed into actual SEAREX service

may have some or all of its power management features enabled during normal operation, having

them all disabled allowed for assessment of worst-case power consumption.

The computers were tested simultaneously in a specially constructed Insulated Chamber

Environmental (ICE) system (locally constructed, Figure 5), which was installed in the NSMRL

#2 man-rated hyperbaric chamber (Hyperbaric Medical Research Chamber, 165 ft (6 ATA)

capable, Figure 6). The ICE system provided the chilled (below 45°) high humidity environment

required for this experiment.

A simple program called SHOWTIME (Appendix C) was run continuously to provide visual

confirmation to the chamber operator that the computer's processor and display were functioning

normally.
ifil ,„ ^^aSHttiiHaWÜgffi^,

"«ft }.*

104P-1

if^-

Figure 5. View of the Insulated Chamber Environment (ICE) System from the Hyperbaric

Chamber Inner Loek.

10
Inboard

Viewine Port

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1 FSfs. ^

•iß

"Ji

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^Ip^^Hlllliill

Hi Hi

SSI

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Will

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Figure 6. Hyperbaric Medical Research Chamber, F-017 N.B. #324 (Chamber #2)

11
With the test computers in place and the SHOWTIME test program running, the inner hyperbaric

chamber door was closed and the ICE system was placed in operation. The environmental

monitoring system was started and initial conditions (temperature <45°F and relative humidity

80-100%) were achieved. A seal on the inner lock door was then established and pressurization

ofthe hyperbaric chamber to 5 ATA was begun at a rate of 10 fsw per hour. During the

approximately 15-minute pressurization, the chamber environmental conditions (temperature and

relative humidity) were maintained as stable as possible and the computers were monitored

regularly for normal operation.

The relative humidity (RH) was measured using two certified hygrometer and temperature

indicator gages (Abbeon Calibration Inc. Model HTAB-176): one installed inside the ICE

system, the other inside the chamber, but outside the ICE system. Their measurements were

manually recorded. The temperature within the ICE system was measured with a thermistor

(Yellow Springs Instrument Co. Model 43TF, 32-120°F capable) connected to an electronic

analog thermometer, and also with a platinum resistance temperature probe connected to a digital

thermometer (EG&G Model 911 DEW-ALL).

1. Computer Testing

To ensure that each laptop was capable of withstanding the high-pressure requirements ofthe

study (5 ATA), candidate computers were briefly pre-tested in a small hyperbaric chamber

(Hyperbaric research chamber, Model 18365 HP, Series 76.1011, Bethlehem Steel, Rated @ 450

PSI) to assess their ability to tolerate a raised atmospheric pressure.

For this pre-test, and the subsequent main test, the internal rechargeable battery was removed

from each computer for safety reasons. It is unknown ifthe batteries and hyperbaric conditions

could precipitate any kind of dangerous situation, such as explosion or fire. Each computer was

then powered by its AC adapter. Since hyperoxic conditions increase the likelihood of

combustion in a pressurized chamber, the AC power adapters were placed outside the hyperbaric

chamber to minimize the potential for fire. As a further safeguard for the main test only, each

computer was also connected via 3-amp fuses and Ground Fault Interrupt protection (GFI)

(Appendix D).

The computers were placed on a shelf in the ICE system, positioned so that they were visible

from the viewing port and on the video monitoring system. They were also arranged to allow

easy access by divers who performed two manned tests. They entered the chamber twice to

conduct keyboard tests and other tests of computer function (Figure 7):

• Approximately 24 hours after initial test conditions were established;

• At the end ofthe seven-day test period, immediately prior to test termination.

On each occasion they halted SHOWTIME and then activated the SEAREX program and tested

the keyboard functions as shown in Appendix E. The testing was designed to take about eight

minutes per computer.

12
Figure 7. View Taken From Hyperbaric Chamber Viewing Port of ICE With Diver Under

Pressure Conducting Computer Testing on the Paravant Computer.

13
After the seven-day test ended the chamber was depressurized at 10 fsw per hour, both

computers were removed from the chamber and their power consumption was measured. For

this test, power was supplied by a regulated DC power supply (Hewlett-Packard Model 6226B

DC), set to 12 VDC as measured with a digital voltage meter (Tektronix Model DM 501 Digital

Multi-meter) and SHOWTIME was initiated. The current was measured with a digital current

meter (Tektronix Model DM 5 02A Auto-ranging Multi-meter).

2. Power Source Testing

The two power sources were placed in a hyperbaric chamber (Hyperbaric research chamber,

Model 18365 HP, Series 76.1011, Bethlehem Steel, Rated @ 450 PS1, Figure 8) equipped with

internal piping to carry an ethylene glycol-based coolant. Each power source was connected to a

computer located outside the chamber via a pass-through connector. The alkaline battery was

connected to the Paravant computer, and the gelled lead acid battery was connected to the Itronix

computer for reasons discussed below.

Chamber environmental conditions were read and maintained using the built-in digital

thermometer and pressure gage. A chiller unit was connected to the chamber piping and set to

maintain chamber temperature between 34°F and 45°F. Because the chamber seal ring was

unable to maintain a perfect seal when the chamber was chilled below 45°F, the pressure was

checked and adjusted (as necessary) every six hours so that it was maintained between 135 fsw

and 155 fsw (5.1 - 5.7 ATA). Manual readings for internal chamber temperature and pressure,

and power source voltages were also recorded at these intervals.

External to the chamber, pass-through connectors were attached to a set of screw terminals.

Connections were made between the batteries, the analog-to-digital converter and the test

computers (which were stowed below the chamber) via these screw terminals (Figure 9). A

circuit diagram ofthe connections made is shown in Figure 10.

Manual voltage readings were periodically taken and recorded approximately every six hours by

test personnel by touching the leads of a digital voltage meter (Fluke 8020 multimeter) to the

appropriate screw terminals. In addition to manual readings, a two-channel analog-to-digital

converter (A/D) (DATAQ DI-150RS Data Acquisition system connected to a Gateway® 2000

Solo® 2300 laptop computer) was connected to the Paravant and Itronix circuits to provide

automated logging ofthe voltage drop. Because the battery voltages were well above the 10

VDC limit ofthe data acquisition system, resistors were required in the interface. Each resistor

was rated to be 470 kQ. Their actual resistances were measured with the Fluke multimeter: Rl =

449 kQ, R2 = 510 kQ. Each channel was calibrated while interfaced with its respective resistor,

and with the DATAQ DI-150RS connected to the Gateway® Solo® laptop. These calibrations

were conducted using a digital voltage meter (Tektronix DM 501 Digital Multimeter) and a

regulated DC voltage source (Hewlett-Packard Model 6226B DC Power Supply).

The Paravant computer has a built-in DC-to-DC converter circuit that allows it to utilize a wide

range of voltages (from 10 to 40 VDC). The alkaline battery delivered a starting voltage of

around 19 VDC when fully charged. During discharge, this value steadily decreased to around

10 VDC, below which it would no longer be a viable source of power for a computer. The wide

14
'fWm,

.fll

Figure 8. Hyperbaric Chamber Open to Load Batteries Prior to Testing

15
Paravant

RLT-515

Test Computer

Itronix

X-C 6250

Test Computer

Figure 9. Hyperbaric Medical Research Chamber F-017 N.B. #324 Under Pressure During

Battery Test

16
Alkaline

Rl

\ D

< II;IIIIKI

Gelled Lead Acid

- 12V

R2

\ I'

'll.'lllllL'l ""

.^2%»-*:^:

Paravant Itronix

Figure 10. Power Source Test Circuit.

range of voltage delivered by the alkaline battery required the use of a DC-to-DC converter;

therefore pairing the Paravant computer with the alkaline battery was the obvious choice.

The Itronix computer required a power supply in a narrower range (11 - 13 VDC). The vendor

did supply an adapter that would allow it to operate on 12 - 16 VDC, but this also consumed

power and would have added an additional load to the battery. By pairing the Itronix computer

with the relatively stable power output ofthe lead acid battery (rated at 12 VDC, 13.5 VDC fully

charged; 11.5 VDC fully discharged), the requirement for an adapter was avoided.

Ill Results

A. Computer Test Results

1. Pre-Test

Both computers operated normally throughout the pre-test.

2. Main Test

Problems were observed with both computers while establishing a seal on the inner lock door of

the hyperbaric chamber. Sealing the inner lock required a quick initial rise of pressure to about

20 fsw in less than half a minute. This rate of pressurization significantly exceeds that expected

in a DISSUB ifthe crew were to remain aboard and survive. A chronology of events in the test

follows.

17
2a. Paravant

The computer failed due to the initial pressurization. At about 20 fsw, the computer appeared to

be in a "move a window" mode, i.e., a window outline appeared and the mouse cursor began to

translate across the screen. The experiment was suspended to permit an investigation. After depressurization, the membrane keyboard appeared slightly ballooned. Some keys were usable; of

these, a few worked normally, including the cursor and mouse keys, and the others required great

effort in pressing to engage. However, most keys weren't usable at all. The machine was set up

again, with its keyboard still somewhat ballooned, and the mouse cursor was carefully placed

away from any areas ofthe screen likely to repeat this problem. The chamber then was repressurized. However, the LCD display soon showed a distorted picture with triangular blotches

of white on each side ofthe screen. At about 40 fsw, the LCD screen developed a black blotch

in its center. The chamber was again de-pressurized at 10 fsw per hour. The display was

inspected and found to be severely damaged with spider-web shaped cracks visible at its center.

The laptop was returned to Paravant. They repaired the unit and performed an ad-hoc design

change by drilling vent holes into the frame ofthe screen to improve its ability to equalize

pressure. The holes were covered with semi-permeable material to maintain the unit's waterresistance.

The experiment was restarted soon after the repaired and modified unit was returned to the lab.

On Day 1 ofthe re-test, the computer functioned normally.

On Day 2 a diver was locked into the chamber to conduct the first operability test. The

membrane keyboard appeared ballooned and did not function properly. The problem appeared to

be due to a false "ALT" key depression caused by the raised atmospheric pressure. After

reviewing potential solutions, a second chamber entry was performed on the same day to attempt

to free the stuck key. The diver managed to get the "ALT" key unstuck by repeatedly depressing

it. When this problem was resolved, the remainder ofthe operability test was run successfully.

The SHOWTIME program ran normally for the next five days.

During the second manned test, on Day 7 ofthe protocol, the computer exhibited keyboard

failure again. It would not respond to any key presses. The mouse keys, however, continued to

function. This failure would have meant that data entry would have been a frustrating process

when it could be done at all. After the chamber was depressurized, the computer was tested

again for operability, but the keyboard problem persisted. It again appeared ballooned and was

not fully operable. The investigators eventually managed to remove the air that was trapped in

the membrane by massaging it out. After a reboot, the keyboard and computer worked normally

again.

2b. Itronix

By design, the Itronix machine resets and reboots when both mouse buttons are depressed for

about 10 seconds. During pressurization, at about 20 fsw, the computer was observed to reboot

itself. The machine was found to reset and reboot itself at pressurization rates greater than 10

fsw per minute. This is because the pressure gradient causes both mouse button switches to

make contact.
The manufacturer requested NSMRL to remove a portion ofthe gasket that seals the PCMCIA

door to the PCMCIA slots in order to allow better pressure equalization. However in so doing,

the watertight integrity ofthe computer was compromised. For this reason, Itronix also

requested that NSMRL angle the base ofthe machine so that the front was higher than the back,

thereby allowing any possible condensation to accumulate at the rear ofthe machine.

The gasket modification resolved the rebooting problem and the computer operated normally

during the establishment of a seal on the inner lock door, and the experiment continued.

The machine passed both operability tests, on days 2 and 7. No problems were noted, except that

the touch-screen feature ofthe computer did not work properly under pressure.

The Itronix computer developed a clock function problem, with the computer's time-of-day

clock losing five minutes a day. This problem was observed regardless of whether the computer

was powered by its internal battery or its AC power adapter. It is not known whether the

computer had this problem prior to testing.

3. Power Consumption

The Itronix computer required an average of 12 watts. The Paravant consumed an average of 16

watts.

19
B. Power Source Test Results

Figure 11 (below) shows the power source voltages over time. The dark curve punctuated with

diamonds is the voltage ofthe alkaline battery pack during its discharge into the Paravant

computer. The diamonds represent manual readings; the line is a series of automated readings.

Although the Paravant consumed more power, the alkaline battery met its requirements for

almost a week, providing 2.5 kilowatt-hours of available power, or 208 amp-hours at 12 volts.

The light curve punctuated with squares is the voltage ofthe gelled lead acid battery during its

discharge to the Itronix computer. The squares represent manual readings and the line is the

automated readings. To run the Itronix for a week should take about 2.0 kilowatt-hours, or 168

amp-hours at 12 volts. However, the lead acid battery powered the Itronix for only 4.75 days,

providing approximately 1.4 kilowatt-hours, or 114 amp-hours. The gelled lead acid battery is

rated for 200 amp-hours when fully charged, so this result was less than expected.

Battery Voltages

15

5 -

«

II

•Alkaline-Manual

• Alkaline-Auto

Lead Acid-Manual

• Lead Acid-Auto • A • •

•

i

—:—:—:—i—:—:—:—|—:—:—:—|—:—:—:—|—:—:—:—|—:—:—:—|—:—:—:—|

3 4

Days

Figure 11. Voltage of Each Power Source During Discharge.

20
IV Discussion

The goal ofthis study was to determine the feasibility of using COTS ruggedized laptops capable

ofrunning SEAREX software, and power sources in a D1SSUB environment, for a period of

seven days. Two ruggedized COTS laptop computers were capable ofsurviving D1SSUB

conditions; however both required minor modification to function when pressurized using the

chamber sealing profile required to seal the inner door ofthe hyperbaric chamber (there are no

dogs on the inner door by design). The Itronix X-C 6250 has undergone a successful at-sea

evaluation by the US Coast Guard in small cutters and rescue stations and performs well in that

environment. The Paravant RLT-515 is fielded by the U.S. Air Force and used under harsh

conditions in its aircraft.

The rather high power consumption ofthe Paravant computer may have been due to its smaller 8

MB RAM. Windows® 95 would have used the FlashRAM for virtual memory, since it

optimally performs with at least 32 MB ofmemory to run programs. A CMOS SDRAM chip,

typically used in laptop design, consumes about 300 mW. The SanDisk FlashRAM card, used in

both laptops tested, consumes about 400 mW; hence, it requires about 30% more power to run.

An 8 MB RAM machine was requested from Paravant, based on the hypothesis that additional

RAM would lead to higher power consumption. The standard configuration ofthe Paravant

laptop is 32 MB or more of RAM. In this study, the Itronix, with 48 MB RAM, required only 12

watts of power.

While one ofthe batteries tested almost met the 7-day specification with respect to endurance

under DISSUB conditions, additional factors such as size, weight, shelf life, and cost would

influence a purchase decision. For instance, while the alkaline pack is more expensive than the

gelled lead acid battery, and has a similar volume, it is 25% lighter. Importantly, it requires no

charging station and would therefore be much simpler to install in a submarine. The shelf life of

the alkaline battery pack is between two and four years, but would otherwise be maintenance

free. A lead acid battery has a float life (its operational life while continuously connected to a

charging station) of up to six years.

A small, light, and low cost power source with long shelf life may soon be available. The United

States Army's Communication Electronics Command (CECOM) is funding an effort at Electric

Fuel Corporation (EFC) to produce a dual voltage (12 or 24 VDC), 50 W zinc-air battery pack

(Figure 12). Designed for use in forward field chargers and communication gear, it is capable of

delivering 1.25 A in the required temperature range. Rated at 400 watt-hours (or 33 amp-hours

at 12 volts), it would be more than adequate to supply 24 hours of power for the SEAREX

system. Seven ofthese "day packs" would be less than 0.4 cu ft and under 20 lbs. Moreover,

according to the NSWC report (Appendix B), their shelf life may be over seven years. However,

it is still at the prototype stage. A field-deployable version for the Army is expected to be

available by 2004.

Zinc-air batteries require oxygen to generate power. Calculations indicate that the quantity of

oxygen used by a zinc-air "day pack" battery is about 45,000 ml per 24 hours of operation, about

the same quantity of oxygen consumed in a 2.5 hours ofrespiration for the average submariner (a

person at rest consumes 300 ml of oxygen per minute4). In other words, a week's worth of zinc21
air battery power (e.g. 7 "day packs") consumes a little less oxygen than one submariner would

in a single day.

iyHflfljjj^l

^^^^^^H

i^^^H^K- - ii f.i^i:i...i.:ij

^^^^^^^^^^^^^^^H ^^^^^^^^^^^^^^H

^^^^^^^^^^^^^^^H ^^^^^^^^^^^^^1 ^^^^^^^^^^^^^^1

Figure 12. Electric Fuel Corp. Zinc-Air Cell.

Zinc-air batteries generate a small amount of hydrogen during discharge. Dr. Terrill Atwater at

NSWC estimated the hydrogen production rate ofthe EFC zinc-air cell to be less than 0.02 ml

per day. Since there are 24 ofthese cells in a "day pack" the rate of hydrogen production in a

SEAREX application would be less than 0.48 ml per day or less than 3.4 ml of hydrogen for a

week. Hydrogen presents no fire or explosion risk until reaching 4% by volume.5

A potential problem with zinc-air battery systems is that they are directly exposed to the

D1SSUB atmosphere, which may make them vulnerable to carbonation. This is the absorption of

CO2 from the air, and that degrades the cell's power output. Since the D1SSUB atmosphere is

likely to contain as much as 6%SE CO2, and ifthese cells become commercially viable, testing

will be needed to determine if a zinc-air "day pack" would degrade too quickly in the D1SSUB

atmosphere.

Provided that the battery goes into full production, it would cost between $50 and $100 per "day

pack" - perhaps about $500 for power for a week. The typical shelf life of a zinc-air battery is

estimated to be 7 to 10 years as long as the airflow into the cathode is restricted. This can be

achieved by taping over the air inflow ducts or storing the entire battery in a sealed container.

22
V Conclusion

The results ofthese tests show that: COTS ruggedized laptop computers can operate, with minor

modification, in a DISSUB environment for at least seven days; and battery power sources can

operate, without modification, in a DISSUB environment for over six days. Ofthe two battery

power sources tested, the Mathews Associates alkaline battery pack would appear to be the best

choice. However, when zinc-air battery packs for the U.S. Army become available, and

presuming a reasonable cost, it is recommended that they be evaluated.

It must be stressed that this study was not intended to be an exhaustive investigation of all

available laptops for this application. Rather it was intended to demonstrate whether it would be

possible to operate the SEAREX software in a DISSUB using existing COTS products.

Successful completion ofthe test should not be construed as an endorsement of any ofthe

equipment tested.

If a decision is made to deploy the SEAREX program at sea, suggested requirements for the

computer are as follows:

• Capable oftolerating:

Atmospheric pressure 0.9 to 5.0 ATA

Up to 90% relative humidity

Temperature 32 to 120°F

Water spray (not immersion)

Salt fog 5% for 48 hours

• Color display - 256 colors, 800 x 600 pixels

• Pointing device (e.g., Itronix "eraser head" joystick; Paravant mouse-cursor keys)

• Sound - Sufficient for audio alarms (Note that neither the Itronix or the Paravant

computer had audio installed in the configuration provided)

• Power consumption < 15 watts

The candidate power supplies should supply at least 200 amp-hours of power under DISSUB

conditions.

23
Acknowledgments

The authors would like to acknowledge Master Diver Jerry Dearie, who built the ICE system and

installed the cooling system within the hyperbaric chamber. Also, the personnel who conducted

the computer testing within the hyperbaric chamber: Walter Von Borstel, Lloyd Lenormand,

Caron Shake, Dave Brannon, Eric Hanson, and Doug Warnock. We also acknowledge

Dr. James Francis for numerous contributions and suggestions, and HMCS(SS) Joe Bertoline for

his review and recommendations regarding ruggedized computers.

24
References

1. Naval Sea Systems Command. Nuclear Powered Submarine Atmosphere Control

Manual, Volume 1, NAVSEA Technical Manual S9510-AB-ATM-010/(U), Revision 3.

Washington DC: Department ofthe Navy, 1992.

2. Bond GF, Workman RD, Mazzone WF. Deep Submarine Escape. Report No.

NMRL 346. Groton, CT: US Navy Medical Research Laboratory, 1960.

3. Windle CM. Survival in a Disabled Submarine. 1NM Report Research No. 95029.

Alverstoke, UK: Institute ofNaval Medicine, 1995.

4. Wilmore, Jack H. Physiology of Sport and Exercise. Illinois: Human Kinetics, 1999.

5. Compressed Gas Association. Handbook of Compressed Gases. 3rd ed. New York: Van

Nostrand Reinhold, 1990:397

25
Appendix A

Vendors' Environmental Specifications

of Each Candidate Laptop

Environmental

Characteristic

Itronix X-C 6250 Paravant RLT Model C

Operating Temperature Range -20°C to 60°C -20°C to 60°C

Rain 4 in./hr. @ ~ 40 psi for 40

min. per axis for all axes per

MIL-STD-810E, Test Method

506.3, Procedure III.

4 in./hr. in 30 m.p.h. wind per

MIL-STD-810E, Test Method

506.3, Procedure I.

Shock 54 repeated 1 meter drops on

all surfaces, edges and corners

per MIL-STD-810E, Test

Method 516.4, Procedure IV.

Procedures I and IV in transit

case, 40Gs, three-times on

each axis and transit drop of

48 in. for a total of 26 drops.

Vibration 0.04g2/Hzover20-1000Hz

random.

MIL-STD-810E, Test Method

514.4 Category 3. Procedure

III categories 6, 8, 10

Procedure I Loose Cargo.

Salt Fog N/A MIL-STD-810E, Test Method

509.3, Procedure I 48 hr. (@

5%).

A-l
Appendix B

Submarine Escape And Rescue Expert System Power

Supply Selection Report

Julie Banner, Jim Barnes, Elisa Shapiro and Clint Winchester

Carderock Division

Naval Surface Warfare Center

9500 MacArthur Blvd.

West Bethesda, MD 20817-5700

Report prepared 15 June 1999.

Table of Contents

Introduction B-2

System Requirements B-2

Active Versus Reserve Systems B-2

Primary Versus Secondary Systems B-3

Modular Approach To Energy Storage B-3

Characteristics Of Major Battery Systems B-4

Primary Battery Alternatives B-5

Secondary Battery Alternatives B-10

Alternative Power Sources B-13

Summary B-15

Recommendations And Conclusions B-16

References B-17

Vendors B-18

B-l
Introduction

The Battery Technology Group ofthe Electrochemistry Branch (Code 683) ofthe

Carderock Division, Naval Surface Warfare Center (NSWCCD) was tasked by the Naval

Submarine Medical Research Laboratory (NSMRL) to provide technical design analysis

and recommendations for a power source for the Submarine Escape and Rescue Expert

(SEAREX) System. This report outlines the benefits and detractions associated with

various possible approaches for providing stored power for this application. The major

categories of power sources considered include primary, secondary, active and reserve

systems. Types of power sources addressed specifically include batteries, fuel cells, and

portable, hand-cranked generators. Issues relating to size, weight, safety, storage, shelf

life, availability, cost and handling are reviewed for the various power source options.

System Requirements

The SEAREX System consists of a ruggedized laptop computer running a software

package designed to provide emergency support to crew who are trapped in a damaged

submarine. The expected power requirements are 12 volts DC output at 15 watts (W).

The desired mission length is 7 days (168 hours), translating to a capacity requirement of

approximately 210 ampere-hours (Ah), or in terms of energy, 2520 watt-hours (Wh). The

temperature requirements for the system are 0°C to 49°C under both storage and

operational conditions. The expected worst-case scenario for battery performance would

involve the combination of prolonged storage at elevated temperature followed by use at

0°C or colder. The power supply must be capable of withstanding shipboard vibration

and shock as described in MIL-STD-810E for harsh environments. Other environmental

requirements include tolerance to 100% humidity and incidental water contact, e.g.,

splashing. The power supply must work under atmospheric pressures ranging from 0.9 to

5.0 ATA, and in all atmospheres with partial pressures of oxygen, nitrogen, carbon

dioxide and hydrogen that would be capable ofsustaining human life.

Active Versus Reserve Systems

An active power supply is designed to deliver electrical power any time a load is applied;

standard alkaline batteries used in flashlights are examples of active batteries. A battery

that is stored in an inactive state such that some activation process must occur before it

can deliver electrical power is a reserve power supply. This name is derived from the

fact that some component ofthe electrochemical cell is held in reserve prior to activation.

Because the active components ofthe electrochemical couple are stored separately in a

reserve system, there is no degradation or self-discharge over time and these batteries can

have very long shelf lives. Reserve systems are usually designed to deliver high power

for short periods oftime. This is often accomplished by selecting cell components such

as separator materials or electrolyte compositions that increase the current carrying

capability when introduced, but would be detrimental to operation over extended wetstorage periods.

B-2
Activation of a reserve power supply may be a manual process or it may be automated.

The overall energy density of an automatically activating reserve power source is lower

than an active system with equivalent power capabilities because ofthe additional

hardware that is needed for the activation system and the electrolyte reservoir. Manual

activation methods include pouring electrolyte into a closed system, submerging an open

system in a bath of conductive fluid (similar to a seawater battery), or installing

electroactive plates into an otherwise complete system. Because the SEAREX System

will be used in a high-stress, emergency situation, the additional step ofmanually

activating the power source is probably undesirable. Also, the unnecessary exposure of

personnel to hazards associated with handling caustic or acid electrolytes is not

warranted.

Primary Versus Secondary Systems

An alternative way ofmeeting a long shelf-life requirement in this application is to use a

rechargeable power source, also known as a secondary power source. Conversely, a

primary power source is designed to be discharged only once, and should not be

recharged and reused. Use of a secondary power source for the SEAREX System would

provide the capability of periodically checking the system without degrading the

available capacity for emergency use. To accomplish this, the SEAREX power supply

could be tied into ship's power, or recharged from an outside source as part ofthe

submarine's standard maintenance schedule. A three to four month stand time between

charges is possible for some secondary power sources. However, a secondary battery

could lose a significant portion of its energy and service life as a result of four months of

storage at high temperature followed by deep discharge in cold conditions.

Modular Approach To Energy Storage

Some commercially available electrochemical systems are only produced in small sizes.

Although small building blocks can be connected in various series/parallel configurations

to generate a package with the desired total energy content, this approach is not always as

straightforward as it might seem. In any battery configuration involving parallel

connections of cells, appropriate electrical safety devices must be included to prevent

self-discharging or cross-charging ofthe parallel strings. Adding diodes in this fashion

results in a loss of useful voltage. Many rechargeable batteries with parallel cell

configurations must include special charge control electronics to maintain balance among

the cells during charging. These requirements add cost and complexity to the

manufacturing process, and can ultimately impact the reliability ofthe power supply.

If a single SEAREX System power supply must contain sufficient energy to meet the 15

watt, 7 day (2520 Wh) requirement, several ofthe small commercial alternatives may be

rejected. However, if a modular approach to meeting the total energy requirement is

viable, then these alternative systems could be considered. This investigation will

include comparison of as many power source alternatives as possible by including the

option ofmeeting total energy requirements with a series of power sources called "day

packs." Each "day pack" would have sufficient energy to run the SEAREX System for a

minimum of 24 hours (approximately 30 Ah). Thus, seven "day packs" would give the

B-3
equivalent system life of a single 210 Ah power source. For the purposes ofthis

discussion, a power supply that contains sufficient energy to meet the 7 day mission

requirement within a single package shall be referred to as a "week pack."

There are both positive and negative implications associated with the use of a modular

"day pack" approach for the SEAREX power supply. On the negative side, the SEAREX

laptop will need an internal back-up battery or flash-card to maintain memory when the

"day packs" are being replaced. Also, the SEAREX program will need to be automated

to alert the user when battery voltage is low and the main power supply requires

attention. Thus, the modular approach to power source selection leads to additional

logistics requirements. On the positive side, having multiple batteries increases the

overall reliability ofthe system by supplying redundancy; ifthere is only one battery on

board and it does not work, that represents a single point failure for the entire system.

Because the "day packs" would be smaller and lighter, this approach provides flexibility

in storage, as well as improved handling. The modular approach also lends itselfto

frequent verification ofthe SEAREX system between mission deployments, since there

could be a designated system verification battery and the remaining batteries could be

retained as dedicated stores. This use scenario could result in deteriorated performance

with a single, large battery because intermittent use of a primary battery usually degrades

its capacity retention over time.

Characteristics Of Major Battery Systems

Table 1 summarizes the basic characteristics of a comprehensive list of battery systems.

This table is copied from the second edition of Handbook ofBatteries, edited by David

Linden. Only those systems that meet the criteria ofreadily available, environmentally

friendly, and ambient temperature will be examined for their practicality with respect to

use in the SEAREX System. However, it is obvious from Table 1 that there are many

alternatives to consider.

B-4
TABLE 6.2 Characteristics of Major Battery Systems3

Battery system

Cuprous chloride

Zinc/silver oxide

Thermal

Practical battery

Anode Cathode

Nominal

voltage, V

Energy densityt

Wh/kg Wh/L

Primary

Leclanche Zn Mn02 1.5 85 165

Magnesium Mg Mn02 1.7 100 195

Alkaline-MnOj Zn Mn02 1.5 125 330

Mercury Zn HgO 1.3 100c470°

Me read Cd HgO 0.9 55c230c

Silver oxide Zn Ag20 1.6 120c500c

Zinc/air Zn 02(air) 1.5 340c1050c

Li/S02 Li so2 3.0 260 415

Li/SOCl2 Li SOCU 3.6 320 700

Li/Mn02 Li MnO, 3.0 230 550

Li(CF)„ Li (CF)„ 3.0 220 410

Li/FeS2 Li FeS2 1.6 240 500

Solid electrolyte Li I2(P2VP) 2.8 200-300 700-)70

Reserve

Mg

Zn

Li

CuCl

AgO

FeS2

1.3

1.5

2.0

60

30

40f

80d

75e

100f

Secondary (rechargeable)

Lead-acid Pb PbOz

Edison Fe Ni oxide

Nickel-cadmium Cd Ni oxide

Nickel-metal hydride (MH) Ni oxide

Silver-zinc Zn AgO

Nickel-zinc Zn Ni oxide

Nickel-hydrogen H2 Ni oxide

Silver-cadmium Cd AgO

Zinc-air Zn 02(air)

Zinc/bromine Zn Br2

Lithium-ion C LLCo02

Lithium-organic Li Mn02

Lithium-polymer Li V6013

High temperature Li(Al) FeS2

High temperature Na S

2.0 35 70

1.2 30 55

1.2 35 80

1.2 50 175

1.5 90 180

1.6 60 120

1.2 55 60

1.1 55 100

1.5 150 160

1.6 70 60

4.0 90 200

3.0 120 265

3.0 200 350

1.7 180 350

2.0 170 250

See Table 1.2 for the theoretical data on these battery systems.

These values are for cells, based on a design and at discharge rates optimized for energy density.

More specific values are given in chapters on each battery system.

" Button cells.

Water-activated.

° Automatically activated 2- to 10-min rate.

With lithium anodes.

Table 1. Characteristics of Major Battery Systems

Primary Battery Alternatives

Alkaline Zinc-Manganese Dioxide

Commercial alkaline cells could be packaged to meet the voltage and capacity

requirements ofthe SEAREX system. The component cells are very inexpensive and

B-5
readily available. There are a variety of companies who specialize in building large

alkaline battery packs. Matthews Associates, Inc. (formerly Battery Assemblers, Inc.)

currently produces the Mark 102, Mod 1 alkaline battery for the AN/BST-1() Submarine

Emergency Communication Transmitter (SECT) Buoy.

Based on manufacturer's data for the Duracell model MN1300, approximately 165 of

these 14 Ah D-size cells could be configured into a 15 volt, 210 Ah battery pack with 11

cells in series and 15 series strings in parallel. The cells alone would weigh 51 pounds

and require 568 cubic inches ofspace. Allowing for another 15 pounds of battery pack

housing and potting material, and adjusting the volume to account for packing density, it

is likely that this "week pack" would weigh about 66 pounds and require 900 cubic

inches ofspace. A battery assembly ofthis size would cost approximately $1000 from

Matthews Associates, Inc.

An alkaline "day pack" battery would have to be much larger than l/7th of a "week pack"

because two parallel strings of D-cells do not have sufficient current density to support a

1.25 A load. It is estimated that at least four parallel strings of 11 cells in series per string

would be needed to meet the 15 W power requirement without severely de-rating the

capacity ofthe cells. This pack would be about one fourth ofthe size ofthe "week pack,"

and might run the SEAREX system for as long as two days.

Some alkaline battery manufacturers produce a 6 V lantern battery that might be used as

a larger building block in similar battery packs. Based on manufacturer's data for the

Duracell model MN918, a "day pack" of 6 volt lantern batteries (rated at 0.66 A current

draw) would require at least four batteries, depending on the current draw and voltage

regulation ofthe SEAREX System. It is estimated that this battery would cost about

$150, or just over $1000 for a one-week supply. This lantern battery "day pack" would

weigh a minimum of 15 pounds and occupy at least 400 cubic inches ofspace. It is

important to note that a lantern battery is simply a single housing containing an array of

cells connected in a series/parallel configuration. It is possible that the internal

configuration ofthis type of battery, which is designed and produced for consumer

applications, might not be robust enough to survive military environments. Ifthe cell

used in the lantern battery is larger than the standard D-cell, it might provide

improvements in weight and volume ifit could be packaged professionally in a "day

pack" or "week pack" configuration.

Alkaline batteries have a sloping discharge curve, and are subject to capacity degradation

under discharge at cold temperatures. The authors estimate that an alkaline battery used

in the SEAREX application would lose as much as 25% of its ambient temperature

capacity when discharged under a 15 W constant power load at 0°C. Prolonged storage,

especially in environments with high humidity, will further deplete the capacity ofthe

battery. For these reasons, it may be necessary to overbuild an alkaline battery with 25%

to 50% excess energy to ensure meeting minimum life requirements under all possible

discharge scenarios. Thus, the weight, volume and cost estimates in the proceeding

discussion should be viewed as minimum values.

B-6
Due to current environmental regulations, alkaline batteries are produced with no added

mercury, and as a result they may be subject to poor performance in response to severe

shock and vibration. Therefore, meeting MIL-STD-810E specifications for harsh

environments may be a concern for these systems. In previous use in military

applications, alkaline battery packs that were hermetically sealed and encapsulated

demonstrated internal self-discharge ranging from moderate capacity loss to uncontrolled

shorting as a result of electrolyte seepage along the interconnections between the cell

strings. Thus, some performance and environmental testing would be necessary to verify

the robustness and determine the final shelf life of any proposed alkaline battery pack.

Zinc-Air

Primary zinc-air batteries are used commercially in small sizes for pagers and cellular

telephones. Zinc-air batteries have been used for over 20 years as the preferred power

source for hearing aids. Larger systems have been built and tested for specific

applications, such as railroad signaling, remote communications and navigational buoys.

Some manufacturers have even marketed zinc-air battery designs specifically for laptop

computer applications. Currently, the United States Army's Communication Electronics

Command (CECOM) is funding an effort at Electric Fuel Corporation to produce a 24 V,

50 W zinc-air battery pack to be used in forward field chargers and communication gear.

A 12 V version ofthis power source is also available, and is reported to be capable of

delivering 1.25 A in the required temperature range. The battery is rated at 400 Wh in

this current range, and should therefore be considered a potential "day pack" for the

SEAREX System. An 800 Wh version could also be made available with a 12 V output.

Provided that the 24 V version goes into full production for the Army, either ofthese 12

V versions could be leveraged offthe Army's production line, and would cost between

$50 and $100 per "day pack." However, the cost to procure prototype units for

preliminary testing is $1500 to $3000 per unit. The typical shelf life of a zinc-air battery

is estimated to be 7 to 10 years as long as the airflow into the cathode is restricted. This

can be achieved by taping over the air inflow ducts or storing the entire battery in a

sealed container.

There are also a limited number of commercially available hybrid batteries that combine

zinc-air technology with traditional alkaline battery technology by adding manganese

dioxide to the zinc cathode. The addition ofthe manganese dioxide provides a significant

increase in pulse current capability. However, in production these batteries generally

have a thicker electrode configuration than some state-of-the-art zinc-air systems, so the

"improvement" from the manganese offsets the limitations ofthe thicker electrodes.

Batteries ofthis configuration are manufactured by Cegasa International of Spain, and are

distributed in the United Sates by Celair Corporation. The model 8AS3/120 cell costs

$61.60, and provides 12 V (open circuit) for 120 Ah with a maximum current rating of

0.08 A, which is much too low of a current capability to satisfy the SEAREX System

requirements. A parallel array of 16 ofthese batteries would be required to meet the

SEAREX current requirements. This configuration would cost approximately $1200,

weigh approximately 140 pounds, and would require more than 9000 cubic inches of

space. However, this battery would have a capacity of almost 2000 Ah, which translates

to over two months ofrun time at 15 W.

B-7
All air cathode batteries require oxygen from the air to generate power, so they would

consume a precious commodity in the submarine atmosphere. As such, it might not be

prudent to select a power source that uses such a valuable resource. Calculations indicate

that the quantity of oxygen used by a 400 Wh zinc-air battery in one day is less than 10%

ofthe amount of oxygen required for an average submariner in one day. It is also

important to note that zinc-air batteries generate small amounts of hydrogen during

discharge. The production of hydrogen onboard submarines is a concern and presents

additional logistical considerations.

Environmental conditions may have an adverse effect on zinc-air systems. Air cathode

cells use a semi-permeable membrane that retains a caustic electrolyte (KOH or NaOH)

in the cell and permits oxygen to diffuse into the cathode. Operation ofthese cells is

critically dependent on the performance ofthe membrane. The permeable membrane

may be damaged by exposure to salt water from inadvertent submersion or spray.

Although an air cathode system should operate independently of atmospheric pressure

when a minimum partial pressure of oxygen is present, it is expected that sudden

increases or decreases in atmospheric pressure could damage the air-cathode membrane

causing rupture or leakage. These concerns highlight the need for test and evaluation of a

prototype system under representative environmental conditions.

Lithium Systems

The classification of lithium primary battery describes a broad family of power sources

that includes a variety of chemistries and sizes. The single common element is the use of

a metallic lithium anode. Primary lithium batteries offer very high energy densities,

function in wide temperature ranges, and can be optimized for high current rate, high

power, or long duration applications. The principal commercial applications for primary

lithium batteries include watches, cameras, computers (memory back-up) and

pacemakers. Specialized commercial applications include powering equipment used in

oil-well logging and embedded sensors. Larger cells are used almost exclusively by the

aerospace and military communities for everything from radios to missiles.

Within the family of lithium primary batteries, there are two major groups: liquid

cathode and solid cathode. Liquid cathode systems, including lithium-sulfur dioxide

(Li/S02) and lithium-thionyl chloride (Li/SOC12), are among the highest energy density

batteries known. In the late 1980s and early 1990s, the authors participated in the

development of a #6-size Li/SOC12 cell for use in the Captor Mine Improvements

Program. SAFT Research and Development Center located in Cockeysville, MD

manufactured the cell. This #6-size cell is slightly larger than a 12 ounce soda can, and

has a capacity of approximately 125 Ah at the SEAREX discharge rate. A "week pack"

could be configured from a total of eight cells, with two parallel strings of four seriesconnected cells in each string. This "week pack" could weight as little as 30 pounds, and

might be as small as 1.5 times the size of a standard "six pack" ofsoda cans. However,

the battery that was designed to use this cell was never introduced into the fleet, therefore

the cell design is not currently in production. In high-volume production, the cell would

cost approximately $500. Significant engineering development would be required to

B-8
design an appropriate housing for this kind of battery, so the authors estimate that the

final cost would be $5000 to $6000 per "week pack".

Liquid cathode lithium batteries pose a significant hazard due to the potential release of

acid gases from pressurized sulfur dioxide or thionyl chloride cells. In the enclosed

environment of a submarine this hazard is emphasized. Although the #6-size Li/SOC12

cell was evaluated and approved for submarine carriage (in a specific battery

configuration), the system was only approved for short-term missions involving swift

deployment. Also, this battery was enclosed in a system housing that was extremely

robust. Although a Li/SOC12 battery design is conceivable for the SEAREX System, the

authors feel that the hazards associated with long-term deployment in a submarine

environment outweigh the potential advantages for this application.

The solid cathode systems include lithium-manganese dioxide (Li/Mn02), lithiumcarbon monofluoride (Li/CFx) and lithium-iron disulfide (Li/FeS2). Solid cathode

lithium batteries offer some intrinsic advantages over liquid cathode systems for longterm storage, and they do not pose the hazards associated with potential leaks of acid

gases. Ofthe three solid cathode chemistries, Li/Mn02 offers the best combination of

cost, configuration and availability.

Both the Ultralife U3360H D-size Li/Mn02 cell and the Ultralife U3VF-K-T Li/Mn02

Thin Cell could be configured into battery packs to meet the SEAREX requirements.

Fifteen D-size cells (arranged as three parallel strings offive cells in series per string) are

required for a 30 Ah "day pack." Conversely, 150 ofthe 1 Ah Thin Cells (with 30

parallel strings of five cells in series per string) would be needed. A "day pack"

comprised of 15 D-size cells will weigh about 4 pounds, without including packaging

material weights like potting and the battery housing. However, since the Thin Cells are

much smaller and lighter than the cylindrical D-size cells, a "day pack" of Thin Cells

might weigh as much as 30% less than one comprised of D-size cells. Because oftheir

rectangular shape, the Thin Cells can be packaged much more efficiently than the D-size

cells. This packing efficiency ofthe Thin Cells would afford at least a 3-fold decrease in

volume over the D cell configuration. When purchased in volume, the Thin Cells cost

approximately 30% more than the D-size cells on a per Ah basis. Also, assembly ofthe

Thin Cell version would be more labor intensive and have a much higher parts count,

which would impact the manufacturing cost. An estimated price range (covering either

configuration and assuming volume pricing) for a Li/Mn02 "day pack" is $500 to $1000,

with the Thin Cell version at the higher end ofthe range. Therefore, the authors estimate

that a full mission complement of primary Li/Mn02 batteries for the SEAREX system

would cost a minimum of $3500 (D cell version) to $7000 (Thin Cell version). EAC

Corporation of Teterboro, NJ would be an appropriate facility for providing battery

assembly capabilities for this type of battery design. The estimated shelf life of a

Li/Mn02 primary battery is seven to 10 years, with a capacity loss associated with selfdischarge of 5% the first year and 2% per year for every additional year.

The United States Army is currently developing Li/Mn02 pouch cells that would be an

excellent building block for the SEAREX power source. These cells would combine the

packaging advantages ofthe Thin Cell with an even larger capacity per unit cell than the

B-9
D-size cell described above. Here, similar to the Electric Fuel zinc-air system, cost

would depend largely on the ability to leverage against large Army procurements. This

approach could represent an excellent opportunity for a long-range product improvement

program.

As with any system that stores energy chemically, and especially with large, complex

assemblies of cells, these batteries have the potential of venting or rupturing with high

pressure and releasing toxic gases and flames. Due to the hazards associated with a

potentially violent failure of a large battery pack, the authors do not recommend

considering a primary Li/Mn02 battery in a "week pack" design for this application.

Prior to use onboard any United States Navy platform, all lithium batteries must undergo

a safety review in accordance with NAVSEAINST 9310.IB of 13 June 1991. In most

cases, testing ofthe battery and the associated system is required. When testing is

required, it is conducted in accordance with NAVSEA Technical Manual S9310-AQSAF-010, " Batteries, Navy Lithium Safety Program Responsibilities and Procedures, "

of 20 July 1988. Also, NAVSEAINST 9310.IB states that "lithium batteries may be

used only when it is established that no other safer, environmentally improved battery

will provide adequate performance to meet an operational requirement." Thus, using a

lithium primary battery as the power source for the SEAREX System should only be

considered ifminimizing weight and volume is mission critical for fielding the system.

Also, consideration must be given to the non-recurring costs associated with evaluating

and testing a lithium battery when comparing power source alternatives for the SEAREX

application.

Secondary Battery Alternatives

Sealed Lead-Acid (SLA)

Valve-regulated, sealed, lead-acid (VRLA or SLA) batteries, such as those used

commercially for marine applications, offer a potential alternative for the SEAREX

power supply. These batteries can be procured from a variety ofmanufacturers in

appropriately sized modules to meet the 7-day requirement. Many ofthese batteries

employ a gelled electrolyte that minimizes the concerns related to electrolyte leakage. A

12 volt, 225 Ah battery manufactured by East Penn Manufacturing Company, Inc. weighs

161 pounds and costs $485. Other manufacturers advertise 12 volt, 200 Ah SLA batteries

for as low as $350. In order to ensure that the SEAREX system is portable (so it could be

moved from a damaged area ofthe submarine to a more secure area) two or more smaller

batteries ofthis type could be used in sequence or connected in parallel. Three, 12 volt,

80 Ah modules costing approximately $125 each might be used in this manner. Seven to

10 smaller versions (50 Ah each) could be fielded as "day packs" for a total battery cost

of about $1000 for a one week supply.

Lead-acid batteries are currently used onboard submarines for reserve power and

propulsion. Thus, fielding additional lead-acid batteries for the SEAREX application will

not represent the addition of a new hazard, or the introduction of a technology that is

foreign to the crew. However, the submarine community requires review and

B-10
qualification of all new types oflead-acid batteries prior to deployment. Although this

qualification process is not usually as demanding as the lithium battery qualification

procedure described previously, it should not be overlooked during consideration ofthe

overall life cycle costs ofthe various power sources.

High-grade SLA batteries produced using glass mat separators have improved vibration

characteristics over other SLA batteries. Designing a protective housing for the battery

could potentially solve shock and vibration issues, ifthey arise. SLA batteries produced

with flame resistant housings are available and may be desirable for this application.

Most SLA batteries designed for portable applications are rated for operation from -15°C

to 55°C, and for charging from -15°C to 40°C. However, the service life of a SLA

battery stored at the upper end ofthe temperature range will be reduced to from 7 years to

1 year, and the self-discharge rate will double for every 10°C over ambient temperature.

SLA batteries must be stored in the charged condition, and last longest when they are

maintained by a float charge; storage in the discharged state will result in battery failure

due to sulphation. These batteries do not take a fast charge, and can be degraded by deep

discharge. Some manufacturers add special catalysts and additives to improve resistance

to damage from deep discharge. SLA batteries generate small amounts of hydrogen gas

during charging and therefore have the same concern associated with their use on

submarines as mentioned previously for zinc-air systems.

Nickel Cadmium (NiCd)

Nickel cadmium batteries are used commercially in a wide variety of portable

applications, such as radios, telephones, video cameras, and power tools. The largest

commercial cell that is available for use as a building block for a 210 Ah system is a 20

Ah cell manufactured by Sanyo. Eleven ofthese cells would be needed in parallel to

produce a "week pack" that could meet the 210 Ah capacity goal. Unfortunately, NiCd

batteries with multiple parallel connections are subject to inconsistencies in charge rate,

and are best recharged on a per-cell level. Special electronics that were developed as an

outgrowth ofthe portable power industry can be used to control charging at the cell level

in a large series/parallel array of cells. At a cost of approximately $53 per 20 Ah cell,

plus the additional costs associated with electronics and assembly, a NiCd battery for this

application would cost 8 to 10 times more than a SLA battery with the same capacity.

The self-discharge rate of a NiCd battery in the SEAREX System could be as much as 4

times higher than a SLA, especially in response to high temperature storage. Fast

recharge is preferable for NiCd systems, and a specialized reverse load charge yields the

best results by promoting recombination ofthe gases generated during fast-charging.

NiCd batteries function best when they are discharged deeply (to 1 V per cell) and

regularly; repeated recharge cycles interspersed with shallow discharge cycles (a likely

use scenario for a rechargeable battery in the SEAREX application) lead to poor

performance ofthe battery known as "memory effect." Outgassing of hydrogen can also

occur in these cells as a result of overcharging. Given these concerns, consumer-oriented

NiCd technology does not seem to be a good fit for the SEAREX application.

B-ll
A possible source for a specialty NiCd battery designed specifically for the SEAREX

system is Acme Advanced Energy Systems. This company produces large NiCd batteries

used in starting-lighting-and-ignition (SLI) applications on military aircraft. Although

the SLI batteries are not directly applicable to this application, technological advances

made by the company (like the use of fibrous nickel plaque materials to replace sintered

nickel oxides) could be applied to a battery for SEAREX. Acme is currently working on

a development effort in conjunction with the U. S. Army to produce NiCd pouch cells

that could be the appropriate size for building a 12 V, 210 Ah battery. Ifthe Army's

development effort is successful, this might represent another avenue for a follow-on

product improvement program.

Nickel Metal Hydride (NiMH)

Nickel metal hydride batteries are hermetically sealed batteries that provide significantly

more capacity per unit than NiCd batteries, and they are not as susceptible to "memory

effect." They generally cost about 1.5 times more than NiCd cells of a similar size.

However, they are not readily available in sizes much larger than 4 Ah, and, like NiCd

batteries, they are also prone to inconsistency in charge rate when too many cells are

combined in parallel configurations. Limited numbers ofspecialized cells are in

prototype production for use in electric bicycle and car applications. These cells have

capacities as high as 100 Ah. For the SEAREX System, although a NiMH battery

produced from commercial cells would be significantly smaller and lighter than a SLA or

NiCd battery with equivalent energy content, it would cost much more.

Lithium Ion

Lithium ion batteries are the most recent family ofsecondary batteries to enter the

commercial market, and are used widely in laptop computers and cellular telephones.

These batteries offer energy densities roughly two to three times higher than NiCd

batteries at comparable discharge rates. Instead of using a metallic lithium anode like

those found in lithium primary batteries, lithium ion batteries have a carbonaceous anode

material that has been intercalated with lithium ions. Provided that the proper charge and

discharge characteristics are maintained, these systems contain no metallic lithium.

However, these cells are susceptible to severe performance degradation and premature

failure if careful charge and discharge management is not maintained.

In order to protect these batteries from abusive current and voltage conditions, they must

include a control circuit and multiple safety shutdown devices. This combination of

expensive electronics and state-of-the-art technology means that lithium ion batteries tend

to be the most expensive of all ofthe consumer-oriented portable power supplies.

Although large, developmental lithium ion cells and batteries have been produced in

limited quantities to support electric vehicle and underwater propulsion efforts, the bulk

ofthe cells produced to date are on the order of 1.5 Ah to 5 Ah in capacity.

Lithium ion batteries are also subject to the same Navy requirements as lithium primary

batteries, and therefore require safety review and testing prior to fielding on a Navy

platform. This combination ofrelatively new technology, limited size factor, higher cost,

B-12
and additional safety requirements make lithium ion batteries an unlikely candidate for a

near-term SEAREX System power supply. In the future, continuing trends oftechnology

advancement and cost reduction could lead to the lithium-ion chemistry becoming a

viable candidate for technology insertion.

Alternative Power Sources

Fuel Cells

A fuel cell is an electrochemical device in which the chemical energy of a fuel is

converted directly into electrical energy. It is like a primary battery that has the fuel and

oxidizer stored externally, to be fed in as necessary. Thus, capacity is limited only by the

amount of available fuel. Fuel cells have been used in non-U. S. submarines as primary

power for air-independent propulsion (AIP), and as a range extender for diesel-electric

boats. Fuel cells are classified by their internal design and resulting operational

parameters. Proton Exchange Membrane (PEM) and Alkaline are the two most

applicable fuel cell technologies for portable power in submarine operating

environments, as the Solid Oxide Full Cell (SOFC) and Molten Carbonate Full Cell

(MCFC) both operate at very high temperatures (600°C to 1300°C).

Some fuel cells have been developed to run on methanol. Most fuel cells that can use

complex fuels (such as diesel and JP6) require extensive pre-treatment ofthe fuel

materials. Most fuel cells function best using hydrogen gas. Various options exist for

hydrogen sources for these systems: bottled hydrogen, metal-hydride converters, and

ammonia crackers.

Most commercially available fuel cell power supplies provide at least 200 W; this is

significantly more power than is needed for the SEAREX System. However, H Power

Corporation produces 35 W and 50 W, solid state, PEM fuel cell systems that include a

Hydrogen Fuel Supply Module with metal-hydride cartridges. The cost for the 35 W

system starts at $3000. Analytic Power also produces a similarly sized and priced power

plant, the FC-25. The Analytic Power version is fueled with bottled hydrogen that is

supplied in 750 Wh-sized tanks. Operating temperature ranges for these commercially

available PEM fuel cells are more limited than for the batteries discussed previously.

Operation at the extremes ofthe specified temperature range for SEAREX may

negatively effect the efficiency and power output ofthese systems.

The safety implications of carrying bottled hydrogen onboard a submarine may limit the

practicality of using the Analytic Power fuel cell. As previously mentioned, there is also

the disadvantage associated with fielding an air-breathing system. The submarine

environment poses a more significant challenge for a PEM fuel cell than a zinc-air battery

because the partial pressures of carbon monoxide and carbon dioxide must be maintained

at low levels to optimize performance and prevent poisoning the system. Also, because

fuel cells rely on balanced airflow through the electrodes, they are likely to experience

performance deterioration in response to variations in environmental pressure. Incidental

wetting or momentary submersion ofthe fuel cell membranes could impair operating

B-13
capability. These myriad performance concerns, coupled with a relatively high cost per

unit, render the fuel cell a poor candidate for the SEAREX power source.

Hand-Cranked Generators

A 70 Watt, hand-crank generator (model 700) is available from Matthews Associates,

Inc. for $2500. This generator weighs 7.25 pounds and occupies a volume of

approximately 175 cubic inches. Both the Army and the Marines have fielded it for

emergency portable power and battery recharging. Although the model 700 is capable of

providing the necessary power to run the SEAREX System, and would also be

appropriate to recharge secondary batteries, the amount of exertion required to operate

the generator is a concern. Personnel running the generator will consume more oxygen

and create more carbon dioxide, and this would be in opposition to the overall goal of

maintaining a life-supporting atmosphere in the submarine for the longest possible

duration. It is possible that the most critical time for use ofthe generator could come

when the available air and physical capabilities ofthe crew are at their lowest. Therefore,

the authors would not recommend fielding this item as the only means of power for the

SEAREX system. Unfortunately, the relatively expensive price makes fielding it as a

back-up system unattractive.

B-14
Summary

Tables 2 and 3 summarize the basic characteristics ofthe most feasible candidates from

the technologies presented above. Table 2 summarizes the possible "week pack"

variations. Table 3 describes options that involve using the "day pack" approach. The

shelf life estimations included in the tables take into account the specific SEAREX

environment, and may not reflect the possible shelf life ofthat chemistry under more

general conditions.

Voltage

(V)

Capacity

(Ah)

Cost per Ah Estimated Shelf

Life

Recharge

Capability

Est.

Weight

(lbs)

Est.

Volume

(in3)

SLA 12 225 $1.50 to

$2.25

1-3 years Yes 160 2285

Alkaline 15 210 $4.75 2-4 years No 66 900

Table 2. Summary Of Various "Week Pack" Power Source Options

Voltage

(V)

Capacity

(Ah)

Cost per Ah Estimated Shelf

Life

Recharge

Capability

Est.

Weight

(lbs)

Est.

Volume

(in3)

SLA 12 50 $2.50 to

$3.00

1-3 years Yes 37.6 483

Alkaline 15 56 $5 2-4 years No 17 to

20

300

Li/Mn02

Primary

15 30 $15 to $20 8-10 years No 3 to 6 60

Zinc-Air 12 33 $1.50 to

$3.00*

7-10 years No 2.65 60

* based on volume pricing

Table 3. Summary of various "day pack" power source options

B-15
Recommendations And Conclusions

Ifthe SEAREX System design can accommodate using a series ofsmaller power sources

that are replaced as necessary, fielding these "day packs" would be preferred over

deploying a single, large power source. The rationalization for this recommendation is

based on the benefits ofredundancy and improved storage and handling, as mentioned

previously. Ofthe four alternatives summarized in Table 3, the authors rank them as

follows:

1) Zinc-Air

2) Alkaline

3) SLA

4) Li/Mn02 primary

By far, the zinc-air "day pack" from Electric Fuel provides the highest energy density at

the lowest cost. However, the success ofthis approach is contingent upon many things.

First and foremost, the U. S. Army contract for a zinc-air portable power pack (or another

similar high-volume commitment) must be in place to generate procurement in the

necessary quantity to make this method cost effective. The relatively small quantities

that would be procured by the SEAREX Program alone would not result in the volume

pricing that makes this alternative so attractive. Because ofthe performance concerns

enumerated previously, environmental testing of a prototype system under representative

conditions must be conducted prior to making a final commitment to fielding this

technology. This will be an expensive effort, primarily due to the relatively high cost of

the zinc-air packs in prototype procurement. However, limited environmental testing of

representative commercial batteries (e.g., cellular phone batteries) might provide relevant

data at a lower cost, and with minimal risk to the program. Finally, use of a zinc-air

system in SEAREX requires gaining acceptance from the submarine community of a

system that consumes oxygen and releases hydrogen. Although there are precedents for

achieving this acceptance, it should not be assumed.

An alkaline battery pack would be the second choice for the SEAREX applications. This

chemistry might be fielded in a "week pack" configuration iflogistical concerns negated

using the modular approach. In either configuration, it has the advantages of being

available from multiple sources, and of being a sealed system that will not impact the

submarine environment. However, the expected shelf life is much shorter than zinc-air,

and the packs will be larger and heavier.

SLA technology is the only rechargeable solution that appears to be feasible at this time.

However, the logistical concerns associated with the maintenance cycle ofthese batteries

require resolution. The shelf life and energy density are both inferior to the zinc-air

system. Use ofthis technology would result in the largest and heaviest batteries ofthe

top four candidates. Although the initial cost is comparable to zinc-air, and less than

alkaline, it is expected that the overall life-cycle cost will be higher because ofthe

B-16
additional maintenance cycle and associated logistical requirements. Acceptance from

the submarine community of a system that generates hydrogen into the atmosphere will

also be required for this system.

Judging by performance criteria alone, the Li/Mn02 primary battery has many

advantages. It is a sealed system that would be about the same size, and last as long as,

the zinc-air battery. However, the cost per unit is seven to 10 times higher, and that

estimate does not include the non-recurring costs associated with meeting the safety

requirements in accordance with NAVSEAINST 9310.IB. The combination of

maximum cost and elevated safety concern results in ranking this approach last among

the likely solutions.

References

Atwater, T., United States Army Communication Electronics Command (CECOM),

personal communication.

Direct Energy Conversion, Third Edition, Angrist, Stanley W., Allyn and Bacon, Inc.,

1976.

Handbook ofBatteries, Second Edition, ed. Linden, David, McGraw-Hill, Inc., 1995.

Power Sources for a Special-Purpose Buoy, West-Freeman, W. A., Banner, J. A., Davis,

P. B. Winchester, C. S., Kilroy, W. P., and Barnes, J. A., NAVSWC TR 91-488, 21 June

1991.

Technical Manual Nuclear Powered Submarine Atmosphere Control, TM S9510-ABATM-010/(C) SUB ATM CONT

B-17
Vendors

Battery Manufacturers andAssemblers

Acme Advanced Energy Systems, 528 West 21st Street, Tempe, AZ, 85282, (480) 894-

6864, http://www.acme-electric.com.

EAC Corporation, 380 North Street, Teterboro, NJ, 07608, (201) 462-2195,

http://www. eacnet.com.

East Penn Manufacturing Co., Inc., Lyon Station, PA 19536,

(610)682-6361.

Electric Fuel Corporation, 1750 Opelika Road, Auburn, AL, 36830,

(334) 502-9001, http://www.electric-fuel.com/cs/defense/index.html.

Matthews Associates, Inc. (formerly Battery Assemblers, Inc.),

645 Hickman Circle, Sanford, FL 32771, (407) 323-3390.

The Power Source, Inc., 2284 Old Middlefield Way, Mt. View, CA 94043,

(800) 847-6947, http://netbox.com/powersource/index.html.

TNR Technical, 17779 Main Street Suite A, Irvine CA 92614,

(800) 490-8418, http://www.batterystore.com/.

Battery Distributors:

Batteries Plus, 844A Rockville Pike, Rockville, MD, 20852,

(301) 738-0606, http://www.batteriesplus.com/stmd.html.

Battery Wholesale Distributors, 2605 Gabriel View Drive, Georgetown, TX 78628, (512)

869-6280, http://www.mywebplace.com/battery-store/.

Celair Corporation, 1455 Oakbrook Drive N. W., Suite 200, Norcross, GA, 30093, (770)

449-8998.

WestCo Battery Systems, Inc., 1645 S. Sinclair Street, Anaheim, CA 92806, (800) 214-

8040, http://westcobattery.com/main.htm.

Fuel Cell Manufacturers

Analytic Power, 268 Summer Street, Boston, MA, 02210,

(617) 542-6352, http://www.analyticpower.com/.

H Power Corporation, 60 Montgomery Street, Belleville, NJ, 07109,

(973) 450-4400, http://www.hpower.com/address.html

B-18
Appendix C

SHOWTIME PROGRAM

SHOWTIME consists oftwo MS-DOS batch files, "SHOWTIME.BAT" and

"TEST.BAT". "SHOWTIME.BAT" runs "TEST.BAT" twice over (two simultaneous

instances ofTEST.BAT, each in its own window), and then enters a loop that displays the

time of day in regular intervals. It also appends to a log file the current time of day as a

means to determine when computer failure occurred. Meanwhile, "TEST.BAT" creates a

large file, prints it out to its window, copies it, deletes it, prints out the copy, and then

repeats.

SHOWTIME serves several purposes. It provides feedback to indicate the computer is

still operating. It keeps the machine fully exercising its FlashRAM, and it also maintains

the computer at a high level of power consumption. The wattage reported for the

Paravant (16 watts) and Itronix (12 watts) were measured during SHOWTIME operation.

C-l
SHOWTIME.BAT

echo off

copy \test\crlf \test\run

copy \test\test.bat \test\l\test.bat

copy \test\test.bat \test\2\test.bat

copy \test\testl.pif \test\l\testl.pif

copy \test\test2.pif \test\2\test2.pif

cd \test\l

start testl.pif

cd \test\2

start test2.pif

cd \test

time < \test\crlf > \test\begunat.txt

echo [[ » runlog.txt

type \test\begunat.txt » runlog.txt

echo ]] » runlog.txt

:TimeLoop

time < \test\crlf » runlog.txt

time < \test\crlf

di r \ /s/b > nul

di r \ /s/b > nul

di r \ /s/b > nul

di r \ /s/b > nul

if exist \test\run goto TimeLoop

exit

C-2
TEST.BAT

di r \ /s/b > ql

copy ql+ql qO

copy qO+qO ql

copy ql+ql qO

copy qO+qO ql

copy ql+ql qO

:StartLoop

if not exist \test\run goto ExitTest

type qO

if not exist \test\run goto ExitTest

copy qO ql

if not exist \test\run goto ExitTest

del qO

if not exist \test\run goto ExitTest

type ql

if not exist \test\run goto ExitTest

copy ql qO

if not exist \test\run goto ExitTest

del ql

if exist \test\run goto StartLoop

:ExitTest

exit

C-3