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1. The battery is continuously overcharged for long peri-
ods of time.
2. A regularly performed duty cycle which allows the
battery to expend only a limited portion of its capac-
ity.
If the nickel-cadmium battery is only sparingly or seldom
used and is left on continuous charge for one or two months at
a time, it could develop the "Memory Effect." On the first dis-
charging cycle, the output voltage could be sufficiently lowered
to reduce the battery’s hours of useful service.
The most common method of causing the "Memory Ef-
fect" is regularly performing short duty cycles. This is when
the battery is operated so that only a portion (50%) of its ca-
pacity is expended. This type of operation can cause the bat-
tery to become temporarily inactive and show a severe decrease
in the ability to deliver at full rated capacity.
Any nickel-cadmium battery showing signs of reduced ca-
pacity should be checked for the "Memory Effect" before be-
ing returned under warranty or scrapped. If the "Memory
Effect" is a fact, a procedure for reconditioning it should be
performed as follows:
1. A complete discharge (deep discharge). This can be
accomplished by turning the radio on and allowing
the battery to discharge overnight.
2. A full charge cycle using an appropriate Ericsson GE
charger.
3. This procedure should be repeated again. Performing
the deep discharge and charge cycle at least twice
should sufficiently restore the battery.
REDUCED CAPACITY IN NICKEL-
CADMIUM BATTERIES:
Nickel-Cadmium batteries in some applications can de-
velop a condition of reduced capacity, sometimes called
"Memory Effect". This condition may occur when:
1. The battery is continuously overcharged for long peri-
ods of time.
2. A regularly performed duty cycle which allows the
battery to expend only a limited portion of its capac-
ity.
If the nickel-cadmium battery is only sparingly or seldom
used and is left on continuous charge for one or two months at
a time, it could experience reduced capacity. On the first dis-
charging cycle, the output voltage could be sufficiently lowered
to reduce the battery’s hours of useful service.
The most common method of causing this limited capacity
is regularly performing short duty cycles; when the battery is
operated so that only a portion (< 50%) of its capacity is ex-
pended. This type of operation can cause the battery to be-
come temporarily inactive and show a severe decrease in the
ability to deliver at full rated capacity.
Any nickel-cadmium battery showing signs of reduced ca-
pacity should be carefully checked before being returned under
warranty or scrapped. If reduced capacity is a fact, the fol-
lowing procedure may restore capacity:
1. Discharge the multicell battery at the normal dis-
charge rate until the output voltage is approximately 1
Volt per cell. This equals 6 Volts output for current
Ericsson GE M-PD personal radio batteries.
Refer to the typical Ni-Cd cell discharge curve in Fig-
ure 19. Note the flatness of the discharge voltage.
Discharging below the knee of the curve does not give
added service. Experience shows discharging below
1.0 Volt is not necessary for reconditioning a cell.
2. A full charge cycle using an appropriate Ericsson GE
charger.
3. This procedure should be repeated again. Performing
the rated discharge and charge cycle at least twice
should sufficiently restore the battery.
PARTS LIST
The above procedure is easily done when using
the discharge analyzer (19B801506P9) with the
Ericsson GE Rapid Multi-Charger
(19B801506P16 or P18).
NOTE
Figure 19 - Typical Ni-Cd Voltage Discharge Curve
LBI-31629
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