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Rev.12/31/97
electro-chemical reaction within the battery, the electrolyte acts as a carrier
for ions and does not change in concentration. Specific gravity remains the
same, and does not indicate the state of battery charge.
for ions and does not change in concentration. Specific gravity remains the
same, and does not indicate the state of battery charge.
6.4 UPON INSTALLATION
6.4 UPON INSTALLATION
Make sure all connections are torqued according to the manufacturer's
specifications. Coat the connections with no-oxide grease.
specifications. Coat the connections with no-oxide grease.
A. Annually
A. Annually
Retorque all connections to the manufacturer's specifications.
6.5 CHARGING
6.5 CHARGING
The density of electrolyte in ni-cad cells does not change appreciably with
charge so specific gravity does not indicate state of charge. This state can be
charge so specific gravity does not indicate state of charge. This state can be
estimated when the battery is on float. To hold battery voltage at 1.40 volts
per cell, a fully charged battery requires about 1 milliampere (excluding load
current) per ampere-hour of capacity. A fully charged 100-ampere-hour
battery draws a charging current (0.001 x 100 = 0.1 amp). The battery is
not fully charged if charging current is higher.
current) per ampere-hour of capacity. A fully charged 100-ampere-hour
battery draws a charging current (0.001 x 100 = 0.1 amp). The battery is
not fully charged if charging current is higher.
A more accurate state-of-charge determination may be made as follows.
With the battery on float charge, record the ampere output of the charger
and the battery terminal voltage. Record the time the above readings were
taken. Then place the charger into the high-rate charge or equalize charge
position. Record both charger ampere output and battery terminal voltage
again. Continue the high-rate charge until the voltage reaches the high-rate
maximum voltage for the system. The state of charge may then be
determined as follows:
With the battery on float charge, record the ampere output of the charger
and the battery terminal voltage. Record the time the above readings were
taken. Then place the charger into the high-rate charge or equalize charge
position. Record both charger ampere output and battery terminal voltage
again. Continue the high-rate charge until the voltage reaches the high-rate
maximum voltage for the system. The state of charge may then be
determined as follows:
1. The battery is fully charged if the high-rate charge voltage is reached in
less than 1 minute and the current output of the charger drops to near
the float current measured above.
the float current measured above.
2. The battery is in need of a charge if the high-rate charge voltage is not
reached in 1 minute or less.
3. The battery is in need of a charge if the charging current is greater than
the float current after 1 minute or more on high rate. Continue the high-
rate equalizing charge until the current is nearly the same as the
measured float current. Record the charge on form POM-133C.
rate equalizing charge until the current is nearly the same as the
measured float current. Record the charge on form POM-133C.
A. Initial Freshening Charge
A. Initial Freshening Charge
An initial freshening charge should be given to compensate for self discharge
losses during shipment and storage. If the cells have been shipped filled and
charged, placing the battery on float will probably be sufficient. If the cells
were shipped discharged, they must be charged according to the
manufacturer's instructions as to voltage level and time. Inspect all cells for
losses during shipment and storage. If the cells have been shipped filled and
charged, placing the battery on float will probably be sufficient. If the cells
were shipped discharged, they must be charged according to the
manufacturer's instructions as to voltage level and time. Inspect all cells for