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 TM 5-684/NAVFAC MO-200/AFJMAN 32-1082
hazard exists, they may not be concerned because
ance in developing a maintenance program for bat-
nominal cell voltages are only 1.2 to 2 volts per cell.
teries which they supply. All manufacturers have
Another hazard occurs when there is an accidental
maintenance instructions for their cells and some
connection between positive and negative points,
will conduct maintenance seminars or presenta-
which can cause arc or a possible battery explosion.
tions. This important source of information should
(1) Possible effects. Batteries in station systems
not be overlooked. Also become familiar with proce-
dures for maintenance, testing, and replacement of
often contain individual cells connected in series (to
storage batteries, as described in ANSI/IEEE 450
form a string), and may reach voltages as high as
and ANSI/IEEE 1106 for lead-acid and nickel-
250 volts. Consider the amount of short-circuit cur-
cadmium types, respectively.
rent batteries can deliver because of their low inter-
nal resistance. Batteries can deliver massive short-
a. Maintenance program. The maintenance pro-
circuit currents, measured in the thousands of
gram selected should address the specific needs of
amperes. Such current can almost instantly make a
the battery installed and should be both consistent
wristwatch, screwdriver, or any other conductive
and regular. Recommended maintenance intervals
path red hot or vaporize the metal. The short-circuit
should never be longer than those required by the
capability of any battery can be obtained from the
manufacturer to satisfy warranty requirements. In
manufacturer and it is recommended that it be
addition, critical load requirements may dictate
posted as a part of the battery room warning notice
more frequent maintenance based upon the impor-
(see table 14-14).
tance of the installation and the impact of a battery
(2) Accidental grounds. It is not uncommon to
failure on the load it serves. Proper maintenance
will ensure optimum battery life, assuming the bat-
find that a ground exists on a battery. This can
tery has been properly sized and installed. When
occur when the electrolyte on top of a cell tracks
allocating time to battery maintenance, ensure that
across the cover, down the plastic jar, and contacts a
it is sufficient for the tasks to be performed. Small
metallic part of the rack. The electrolyte, being con-
inaccuracies that can occur when personnel are
ductive, establishes a ground path.
rushed can result in useless data, and overlooking
(3) Normal safety procedures. When working
of other obvious problems. Wherever practicable,
around batteries, all normal safety procedures
tests should be carried out in a manner that accom-
should be followed, including the use of protective
plishes one or more objectives at the same time. For
equipment. Caution must be exercised in placing
example, a capacity test also can be used to check
meters on top of batteries. Under certain conditions,
for high connection resistance.
meters with enclosures partially made of metal can
b. Battery specifics. A maintenance program must
cause a short circuit and sparks. Metal objects
address the specific battery installed. Although the
should never be placed on top of batteries, and
tests and frequency of maintenance may be the
metal tools used on batteries should be insulated to
same, there are subtle differences between batter-
prevent accidental short circuits. Generally, a
ies. For example, the nominal float voltage will vary
ground detector is provided as part of the dc system,
between lead-antimony and lead-calcium cells. In
most often in the battery charger. Be certain to
addition, the total float (terminal) voltage will be
check the ground detector before starting work. If
an unintentional ground exists, it should be cleared
different when the total number of cells provided
varies (as for nickel-cadmium units) even though
before work begins.
the nominal voltage per cell may be the same. For
(4) Two-person teams. Always have two per-
instance, a nominal 24-volt lead-acid battery sys-
sons assigned to perform battery maintenance in-
tem can be made up from 12 to 14 cells of the same
spections. One person takes the readings and the
type. Another consideration is that the float voltage
other records them. They should not work on differ-
used will vary with the nominal specific gravity of
ent parts of the battery at one time because they
the cell.
could become two points, completing a circuit to
(1) Battery system replacement. When a battery
ground.
is replaced, the new battery often continues to be
14-4. General battery maintenance proce-
maintained in the same manner as the old one.
dures.
However, the new battery may be of a different alloy
or nominal specific gravity, or may contain a differ-
Always follow the battery manufacturer's mainte-
ent number of cells. Maintenance personnel may
nance procedures and check warranty require-
not recognize the differences, which can lead to ir-
ments. Battery temperature examples given are not
reversible damage.
justification for ignoring the temperature require-
(2) Battery condition. Battery condition can be
ments given in this chapter for battery rooms or
areas. Manufacturers will normally provide assist-
assessed based upon comparisons of current and
14-3
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