TM 116140203141
ing 2 hours. The correct level of electrolyte is -inch
plates. These changes in electrolyte level should only
above the top of the plates of a fully charged cell that
be made if absolutely necessary and only in cells con-
has been at rest for the prescribed period of time. Re-
taining adequate head space over the plates.
fer to TM 11-6140-203-14-2 and TM 11-6140-
212. Foaming
203-14-3 respectively for rest time limitations for
specific aircraft and nonaircraft nickel-cadmium bat-
Foam may sometimes be noticed in cells during
teries. Observing the rest time limitations before
charge. It normally does not indicate a defect and is
checking the electrolyte level is an absolute must to in-
harmful only if it results in excessive overflow. Foam-
sure that the cell is not overfilled or underfilled. How-
ing is more likely to occur after adding water and
ever, some modification in electrolyte level height or
should disappear after a few cycles of operation. Con-
rest time after charging may be required depending on
tinued foaming indicates contaminated electrolyte and
the equipment used for charging and the environment
the cell should not be used until thoroughly checked
the battery will see in use (voltage regulator setting
for damage. When electrolyte is lost due to foaming in
and temperature). In general, the constant current
new cells, add 31 percent KOH electrolyte to the cell
(CC) chargers used in the battery shop will produce a
rather than water. After the first two charge cycles,
higher apparent level of electrolyte than a constant po-
only distilled water should be added.
tential (CP) charger, since the CC charger normally
charges to a higher end-of-charge voltage. If this is the
istics
case, then it maybe necessary to increase the rest time
after charge from 30 minutes to up to 2 hours and/or
a. Cell capacity decreases when discharged at high
increase the electrolyte to
-inch above the top of the
