BB-451 /U
TM-11-6140-208-15
SECTION 1 GENERAL DESCRIPTION AND SPECIFICATION DATA
1-1 INTRODUCTION
a.
SCOPE. This manual covers the operation, maintenance and repair of the BB-451/U Silver-
Zinc Storage Battery, F8N 6140-889-1027.
b.
PURPOSE. The purpose of the BB-451/U Silver-Zinc Storage Battery is to provide a light-
weight power source for use with man-pack communications and electronic equipment. The silver-
zinc battery is superior to the lead-acid, nickel cadmium, and silver-cadmium batteries in watt-hour
capacity per-pound of battery weight. The silver-zinc battery is also superior to the lead-acid battery
in voltage regulation during discharge. The construction, maintenance and personnel precautions
pertaining to the silver-zinc battery vary greatly from the more familiar lead-acid battery. This
manual provides adequate operational and maintenance data on the BB-451/U Silver-Zinc Storage
Battery to ensure proper use, thus minimizing the probability of injury to the user or damage to the
battery.
1-2 PHYSICAL AND FUNCTIONAL DESCRIPTION (see Figures 1-1 to 1-3 and Table 1-1)
a. PHYSICAL DESCHIPTION. The BB-451/U Storage Battery Is a rechargeable, SILVER-ZINC,
ALKALINE ELECTROLYTE battery, rated at 25 ampere-hours (AH).
The battery contains 16 series-connected cells with a nominal cell voltage of 1.5 volts, producing a
total nominal battery voltage of 24 volts. Each group of four cells is combined within separate plastic
cases called mono-blocks. A battery, therefore, contains four monoblocks. Each cell within a
monoblock case consists of eight silver (positive electrodes) and eight zinc (negative electrodes) plates.
Each plate is enclosed within several layers of cellulose material. The monoblock casings are made of
molded plastic, and the four cells within the monoblock are equipped with threaded-screw nylon vent
caps. Each monoblock is replaceable as an assembly.
All metal parts of the battery are passivated and nickel or silver plated to resist reaction with the
electrolyte.
The overall physical size of the BB-451/U is 7-11/16 inches_high, 11-9/16 Inches long and 4-9/64
Inches wide. The battery weighs 16 pounds when filled with electrolyte.
Overall Dimensions (Inches)
7- 11/16 H x 11- 9/16 L
..........................................
x 4- 9/64 W
Weight Filled (Pounds) .
16 lbs ( 7. 3 kg )
Cathode ..........................
Zinc
Anode ................ ,............
Silver Oxide
Electrolyte..........
40% Potassium Hydroxide- KOH
Nominal Cell Voltage .....
1,5 V
Nominal Battery Voltage .
24 V
Nominal Arnpere-Hour Capacity
25 Ah
Open Circuit Voltage .......
29.76 V
Watt- Hour/Pound ............
59
Watt-Hour/Cubic Inches..
4. 4
Voltage Regulation ..........
Good
Discharge Rate (Maximum, Amperes)
25 A
Cycle Life (Cycles) ......
10-30
The input current of the RT695A / PRC41 is 1.9A in receive mode, or 3.1A in transmit mode.
