From the Camp Crowder Central Signal Corps School Workbook
In the Signal Corps, the two types of batteries most commonly used are the BA-23 and the BA-30. Both of them are particularly adaptable to the various types of flashlights, telephones, radios, telegraph, test-sets and switchboards.
Batteries deteriorate rapidly.
Batteries are often dated. Use the oldest first.
Heat is harmful to batteries.
Batteries must be stored in a dry place.
Remove Batteries from Equipment before storing or when not in use.
A. Connected in Series
B. Connected in Parallel
C. Connected in Series-Parallel