The BA–1 battery, formerly known as Signal Corps Type A, is made up of two cells of a commercial type connected in series. They are put end to end in a cardboard tube which holds them together and also protects them mechanically. The carbon terminals of both cells are tipped with a brass cap, and the tip of the lower cell is connected by a soldered strip of metal with the bottom of the zinc can of the upper cell. The cardboard tube is open at both ends. Thus the carbon tip of the upper cell is the positive terminal of the battery and the zinc can of the lower cell is the negative terminal. Each cell is about 3 inches long and 14 inches in diameter. The over-all dimensions of the battery are about 6% inches long and 11's inches in diameter. Its weight is between 8 and 9 ounces, or 0.53 pound. It has an open-circuit voltage of 3.1 volts; an internal resistance of 0.3 ohm, which may increase to 0.4 ohm as the battery approaches exhaustion; a short-circuit current of nearly 10 amperes; a shelf life of 6 months; and a service life of 15 to 25 days, depending on the use to which it is put. It is to be noted that each cell has an open-circuit voltage of 1.55 volts; an internal resistance of between 0.15 and 0.2 ohms; and a short-circuit current of nearly 10 amperes. The battery is at present used by the Signal Corps in the following equipment:
- EE-1A. Buzzerphone.
- EE-3. Field telephone, model 1917 (buzzer telephone).
- EE-4. Portable telephone (camp telephone, model A, with condenser).
- EE-4A. Portable telephone (camp telephone, model 1917, without condenser).
- ?? EE-8. Field telephone, to replace EE–3, EE-4, and EE-5 (development not completed). ":
- EE-9 Antiaircraft artillery telephone.
- EE–63. Service buzzer.
- EE-64. Monocord switchboard operator's set.
- EE–65. Universal test set.
- EE–66. Balloon telephone winch set.
- EE–67. Balloon telephone basket set.
- EE-76. Simplex telegraph set.
- SCR-49. Radiotelegraph pack set
- Training Pamphlet no.7 Primary Batteries Jun., 1922 W.D.D. NO. 1112