MIL-B-18F
4.7.2 Electrolyte penetration. Applicable specimens of materials and components shall be placed on a metal plate,
and a cylindrical plastic tube, 2 inches (50.8 mm) high with an internal diameter of 1.5 inches (38.10 mm), shall be
clamped over the material. The tube shall then be filled to a depth of 1 inch (25.4 mm) with an aqueous solution of the
appropriate electrolyte (zinc chloride, 50 percent by weight, for Leclanche-type batteries, and potassium hydroxide, 31
percent by weight, for mercury-type batteries). A metal electrode shall be inserted into this solution to a depth of
approximately .5 inch (12.7 mm). A direct-current potential of 22.5 volts shall be applied between this electrode and
the metal plate, with a milliammeter of the proper range in the circuit. The test shall continue for a period of 72 hours,
but may be terminated if failure occurs sooner. For small extruded plastic jackets, a comparable test shall be
performed (see 3.6).
4.7.3 Dielectric withstanding voltage (see 3.7). Batteries shall be tested in accordance with method 301 of
MIL-STD-202. The following details and exceptions shall apply:
a.
Special conditions: Applicable specimens of material and components shall be conditioned for 48 hours at
150 °F ±2 °F (65.6 °C ±1.1 °C) and a relative humidity of 50 ±15 percent; then for 1 hour at 70 °F ±5 °F
(21.1 °C ±2.8 °C) and a relative humidity of 50 ±15 percent. Each specimen of material shall then be placed
between two electrodes in such a manner that the electrodes shall make contact with both sides of the
specimen being tested. Each electrode shall have a diameter of 2 inches (50.8 mm) with the edge rounded
to a radius of .25 inch (6.35 mm), so that the center surface of a circle 1.5 inches (38.10 mm) in diameter.
The specimen shall extend at least .5 inch (12.7 mm) beyond the electrode surfaces around the entire
circumference of the electrode to prevent flashover at the edge of the specimen.
b.
Test voltage: 1,000 volts, rms.
c.
Duration of application of test voltage: 60 seconds.
d.
Source of test voltage: A transformer rated not less than 500 volt-amperes, capable of delivering up to 10
kilovolts, rms to the electrodes.
e.
Monitoring: Specimens shall be monitored while the test voltage is at its magnitude for evidence of
breakdown of insulations or damage.
For small extruded plastic jackets, a comparable test shall be performed.
4.7.4 Contact resistance of terminals (see 3.7.9.4.2 and 3.7.9.5.2). Battery terminals shall be tested in accordance
with method 307 of MIL-STD-202. The following details and exceptions shall apply:
a.
Test current: 5 amperes.
b.
Number of insertions and withdrawals: 10, complete for snap-on terminals, using a mating stud for the
socket; and 20 complete for socket terminals, using a mating plug for the socket.
c.
Number of test activations on which measurements are to be made: During engagement numbers 1, 5, 6,
and 10 for snap-on terminals, between the stud and socket; and during engagement numbers 1, 10, 11, and
20 for socket terminals, between applicable pins of the mating plug and the socket.
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