BA–8.—This battery is made up of 15 cells in series and is contained in a waterproof cardboard box, sealed on top with a sealing compound, through which the two terminal wires extend, the positive one being red and marked with a plus sign, and the negative one black and marked with a minus sign. The number of cells, the voltage, and the method of assembly is the same as in BA–2, but the individual cells are larger, and hence the battery as a whole is larger and heavier. Each cell is about 2-3/8 inches long and 1-1/4 inches in diameter. The over-all dimensions of the battery are 4 by 6-1/2 by 3 inches high. The weight is about 4.5 pounds. The battery has an open-circuit voltage of nearly 23 volts, an internal resistance of 33 ohms, a shelf life of 6 months, and a service life of 1 month. A single cell has therefore an internal resistance of about 0.2 ohm and a short-circuit current of about 7 amperes. The battery is made up of standard commercial cells and for this reason its service life of one month (720 hours) is much longer than the 100 hours of BA-2 under the same conditions. It is to be noted that BA-2 and BA–8 are interchangeable as to voltage, service, etc., except that BA–8 is too large to go into battery compartments designed only for BA–2. In this case BA–8 may be used by putting it near the set box and connecting it to the proper binding posts or clips by extra lead wires. The same precautions must be observed in handling BA–8 as BA–2; that is, the terminal wires must not come in contact with each other and short-circuit the battery; when the battery is not in use, the wires should be coiled up on top of the battery, and the wires should not be cut off.
- Training Pamphlet no.7 Primary Batteries Jun., 1922 W.D.D. NO. 1112