the shelf life of a nicad battery is 1,000 cycles.
what is the shelf life of a nicad battery?
1,000 cycles
an effect with similar symptoms to the memory effect is the so-called "voltage depression" or "lazy battery effect". this results from repeated overcharging; the symptom is that the battery appears to be fully charged but discharges quickly after only a brief period of operation. in rare cases, much of the lost capacity can be recovered by a few deep-discharge cycles, a function often provided by automatic battery chargers. however, this process may reduce the shelf life of the battery. if treated well, a ni–cd battery can last for 1,000 cycles or more before its capacity drops below half its original capacity. many home chargers claim to be "smart chargers" which will shut down and not damage the battery, but this seems to be a common problem.
nickel–cadmium battery
with the exception of the prc 349 and uk rt 350 which are 12 volt (nominal), the manpack and portable sets and their chargers were almost all nominally rated 24v dc (direct current) to match the british army's choice of 24 volts to power its vehicle systems. the direct current charging units (dccu) was used to float charge (provide a top up charge while the set was in use) the manpack battery, while it was mounted in a vehicle, using a clip in kit for example. it could also provide a full charge cycle over 4.5 hours from flat, switching itself out of circuit when complete. (a clip-in kit locked the radio in a convenient frame for rapid deployment when dismounting, and had the charger as part of the installation.) there were a few exceptions where 24 volts was not used in vehicles, such as in the general service (gs) landrover where a 12v system was used for example. a 12 volt dccu was provided. the clansman 24v 4ah nickel cadmium battery was prolific and for convenience an alternating current charging unit (accu) was provided for use in barracks where up to sixteen batteries could be charged simultaneously or singularly. all of these chargers worked the same, basically providing an appropriate charging current while sensing the battery temperature to detect when charging was complete, achieved by measuring the voltage across two sets of a series pair of silicon diodes in the battery itself, one series pair would sense the internal temperature of the cells the other series pair fitted close to the outer case of the battery to sense ambient temperature, the difference in temperature being used to determine the state of charge. one drawback of the clansman 24v 4ah nicad is that failure of these diodes makes batteries unserviceable. also due to partial charge cycles due to the 'memory effect' of the nicad cells. a discharge process could have prevented such failures, but was not provided for in either the dc or accu. specialists can rebuild the unserviceable clansman nicad battery.
clansman (military radio)