Electrical Projects One of the more recent developments in home appliances is the "cordless" feature made possible by nickel-cadmium, sealed-cell, rechargeable batteries and some form of charging device. The charging device is usually a sealed unit which is serviced by direct replacement from the manufacturer, but it rarely is the culprit in battery-operated appliance problems. The most frequent cause of malfunction in these types of appliances is the battery itself. Either it has permanently lost its capacity to take a charge and must be replaced or it has suffered a temporary capacity loss as the result of improper charging procedure. Unfortunately, a low-voltage reading is insufficient to determine whether the loss is temporary or permanent and, as a result, the home-appliance repairman can hardly avoid inadvertently discharging many good batteries. Since the cost of these batteries is considerable it makes good sense to invest in a device which can determine the type of capacity loss, and one that is able to correct the loss should it be temporary.

Temporary loss is usually the result of periodic, or "programed" charging sequences which may not be sufficient to counter the state of discharge in the battery. The rechargeable-battery tester corrects this condition by deep-discharging the battery several times and recharging to restore its original capacity. This series of deep-discharges and chargings takes about P/2 hours for the average battery and is fully automatic. If the battery is restored to full capacity, it is an indication of improper operating conditions with regard to the charging unit's ability to restore the battery to maximum capacity.




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Home > Electrical Projects > Tools And Components > Rechargeable - Battery Tester

October 12, 2008