Ericsson LBI-31629B manual Parts List, Reduced Capacity In Nickel- Cadmium Batteries

PARTS LIST LBI-31629

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.

NOTE

The above procedure is easily done when using the discharge analyzer (19B801506P9) with the

Ericsson GE Rapid Multi-Charger (19B801506P16 or P18).

Figure 19 - Typical Ni-Cd Voltage Discharge Curve

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