Figure 5-2. Electrolyte Level Adjustment
5-7. Periodic Service Procedures
For batteries returned to direct support or general support for quarterly or every 100 discharge-charge cycles
mainte- nance service, proceed as follows:
Refer to TM 11-6140-203-15-1 for information concerning the temporary loss of
capacity of a nickel-cadmium battery and the discharge method recommended to
restore the rated capacity to the nickel-cadmium battery.
The following discharge fixtures are available for completely discharging all the cells in
the indicated battery:
(1) Battery, Storage BB-422/U, use fixture, NSN 6110-00-179-8273.
(2) Battery, Storage BB693A/U, use fixture NSN 6110-00-014-6225.
Discharge the battery using the proper load fixture and the instructions contained in (4) below. If a
load fixture is not available then proceed as described in (1), (2), and (3) below.
(1) Connect the 0- to 7.5-ohm, 1.000-wan variable resistor (item 8, app E), two Multimeters
AN/USM-223, knife switch (item 7), and nickel cadmium battery to be discharged as shown in figure 5-3. (Be
sure that the knife switch is in the open position.)
(2) Close and open the knife switch as necessary while adjusting the 0- to 7.5-ohm variable
resistor for a resistance value high enough to permit the discharge cur- rent to flow at approximately the 2-hour
rate of the battery. Monitor the terminal voltage of each cell during dis- charge using the AN/USM-223. When
the terminal voltage of a cell reaches 0 volts, place a shorting device