TM 10-6140-200-14
can accept, up to maximum charger output, and then
battery is a charge given to batteries in storage or during
taper the input sharply, when cells begin to gas, to keep
inactive periods to replace losses due to self-discharge and
finish rates low. These chargers do not require adjust-
to assure that every cell is periodically brought to a fully
ment. A typical taper charge is illustrated by Figure 2-4.
charged state.
2-10. Types of Charge
2-11. Charging Precautions
a. When connecting the battery to the charger always
a. Normal charge. The three generally recommended
types of normal or routine charges, following a deep
connect positive (+) to positive and negative (-) to
negative terminals.
discharge, are: (1) modified constant voltage charge, (2)
two-rate charge, and (3) taper charge. Since these
b. Always recharge the battery as soon as possible
methods are described in Paragraph 2-9, "Charging
after discharging.
Methods and Equipment," no further definition of normal
charges will be included here.
c. Keep vent caps tightly in place while the battery is
being charged except when servicing the cell or when
b. Boost Charge (Quick Charge). A boost charge of a
storage battery is a partial charge, usually at a high rate
taking specific gravity or temperature readings.
for a short period. Such a charge is given in an emergency
d. Make sure that battery and charger voltages and
when it is believed that the ampere-hour capacity of the
battery may be less than normal and insufficient to
ampere-hour ratings match when preparing to charge
complete a planned period of work. A boost charge may
batteries.
also be used when it is not possible to give a battery one
of the recommended types of normal charge.
e. Make certain that charging area is well ventilated.
c. Equalizing Charge. An equalizing charge of a stor-
f. Prohibit smoking and open flames in charging area.
age battery is a prolonged charge, usually at the finishing
rate or less, to correct any inequalities of voltage or
g. Tools or other metal objects should never be
specific gravity which may have developed between cells
allowed to contact intercell connectors.
during service. It consists of following a normal charge
with an extended charge of 3 to 4 hours at a rate no
h. Observe safety and health practices defined in
higher than the finishing rate. In motive power applica-
tions, a battery should receive an equalizing charge only
preparing for charging, to take the following precautions:
when differences in individual cell voltages or specific
(1) Wear protective gear provided.
gravities indicate the need. Frequent and unnecessary
equalizing charges cause excessive overcharge which can
(2) Use proper mechanical equipment to move or
result in significant loss of battery life. Generally, equaliz-
lift batteries.
ing charges will not be required if a battery is healthy and
is cycled almost daily. On the other hand, if a battery is
(3) Provide acceptable fire extinguishing equipment.
cycled no more than twice a week, a monthly equalizing
charge will normally keep it in proper condition.
(4) Know the location of the nearest source of
fresh water for emergency use.
d. Freshening Charge. A freshening charge of a storage
Section III. ROUTINE MAINTENANCE
2-13. Charger Adjustment
2-12. General
Make sure that the charger adjustment, for control of
The modern industrial battery is designed and built to
charging rates and cut-off are correct. This will assure that
give an average of 1500 cycles of charge and discharge
the batteries are properly charged with no excessive
during its life, depending upon the application and the
operating environment. The exact length of the service
over-charge. Batteries that are overcharged regularly will
life will depend, to a great extent, upon the care the
need water more often, and cell temperatures usually will
battery receives. The following maintenance procedures,
be higher than normal. If either condition is evident,
carried out at the proper time, will do much to prolong
adjust the charge rate downward, in those chargers which
the life of the battery and provide efficient, satisfactory
have provision for adjustment, so it is between a normal
service.
finish rate and one-half normal finish rate. Also check the
2-6
