TM 11-6140-203-14-3
c.
Check Polarity Position of Cells. Check the polarity position of each cell or group of cells to be sure
that they are connected properly. The polarity of each cell is indicated by a plus (+) sign molded into the cell
cover adja- cent to the appropriate cell post. For the cell layout for a specific battery, refer to the cell layout of
that specific battery (chap. 2).
d.
e. Clean Fillercaps. Clean the fillercaps by following the instructions contained in paragraph 4-7e.
NOTE
Refer to paragraph 2-3, TM 11-6140-203-15-1 for detailed information concerning the electro-chemical
action when charging a nickel-cadmium battery.
WARNING
Explosive gases may be released during charging. Check to be sure that the charging area is. well
ventilated. Do not use matches or an open flame in the charging area. Guard against short circuits;
resulting arcs may cause an explosion. Do not disconnect the charging cable from the battery until the
battery charger has been turned off. Explosions or serious burns may result.
f.
Charging. Charge the battery using the constant- voltage method or the constant-current charging
method as given in (1) or (2) below. At the end of charge, before
the current has been shut off, the individual cell voltages should be checked for uniformity. Cell voltages
should be within 0.1 volts of each other. Low cell voltage (under 1.2 volts) may indicate a shorted cell, while
high voltage (over 1.9 volts) indicate either a dry cell or bad connec- tion.
(1) Constant-Voltage Method. Table 5-1 provides the constant-voltage charging rate required for
temperature, number of cells, and time to accomplish the charge cycle. For example, for a temperature of 800
F and a battery containing 19 cells, charge for 2 hours at 30 volts. Periodically monitor the constant-voltage
charging rate by placing the test prods of a voltmeter across the battery terminals and adjust the output of the
battery charger, as necessary).
(2) Constant-Current Method. Table 5-2 provides the constant-current charging value required for
the specific ampere-hour rating of a battery and the amount of time it normally takes to accomplish the charge
cycle. For example, for a fully discharged battery, charge a 34-ampere-hour battery at 21.3 amperes for 2
hours, 10.6 amperes for 4 hours, or 6.8 amperes for 7 hours. If the battery does not meet the minimum end-of-
charge voltage, check individual cells for low voltage .If no low cells are present then charge must be continued
until the minimum voltages are reached. A new battery may re- quire 20-30% more charge than normal on its
very first charge
.
Table 5-1.Constant-Voltage Charging Rate
Table 5-2. Constant-Current Charging Rate and End-
Table 5-2. Constant-Current Charging Rate and End-
of-Charge Voltage
of-Charge Voltage-Continued
5-2
