All WW2 German field telephones were OB (Ortsbetreib Batterie) telephones… That is, the microphones in the handsets were powered by batteries in the telephones. In the Feldfernsprecher 33 (FF33), the OB43, and the Tischfernsprecher 38, the batteries were 1.5 volts and could be liquid filled or air activated.
Liquid filled batteries had the designation F30 and air activated batteries had the designation T30. F30 batteries were used pre-war and T30 batteries were used during the war. Both the F30 and T30 measured 55mm wide, by 55mm deep, by 125mm tall. With these dimensions, the batteries fit snugly in the battery compartments of the field telephones.
The battery labels included a code, for example, “ELF” or “ELL.” The first letter of the code, “E” stood for “element,” which is “battery” in German. The second letter stood for the battery dimensions. “L” is 55x55x125mm. The third letter stood for the battery type. “F” is liquid filled. “L” stands for “Luftsauerstoffelement” or air activated. So, an F30 would have the code ELF and a T30 would have the code ELL.
F30 and T30 batteries are no longer in production. The last T30 battery was made in the 1960s. But, fear not, WW2 German field telephones can still be made to operate with modern 1.5 volt batteries, e.g. a “D” cell.
Reproduction T30 batteries are available from several sources. These reproductions have vintage labels but contain modern batteries inside.
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WW2 German Field Telephone Equipment 