Automatic 9 volt Battery Charger
Good care given to your NiCad batteries will ensure a long life. However, they do need to be handled and charged with special care. It is therefore important to first discharge the NiCad to 1 Volt per cell, ensure that the battery is discharged, and then start the charge cycle. recommend a charge current of 1/10th the capacity for a duration of about 15 hours uninterrupted. In reality, we learn some hard lessons when we forget to switch the charger off after the 15 hours and find that one or more cells inside the battery no longer accept a charge. That is the very reason that the circuit above is fully automated. The only thing to do is connect the battery and press the 'Start' button. When the discharge cycle is finished the circuit switches over to charge for 15 hours. After the 15 hours the circuits maintains a trickle charge to keep the battery 'topped-up Before I go into the schematic details I like to explain some of the component descriptions in the schematic. Jan Ha