battery fitness centre

1 II 0 battery fitness centre Tomezzoli This circuit is designed primarily for maintaining lead-acid batteries that are often not used for long periods in good working order. It charges the battery, after which the battery discharges slowly through its internal resistance and the present circuit. When the state of charge reaches a predetermined level, the charger is switched on again, the battery charges, and so the cycle repeats itself. The circuit is based on Schmitt trigger Ti /T2. Zener diode D7determines the state of charge at which the charger is switched off. Resistor R2 provides the required hysteresis. With the mains disconnected and no battery con- nected to the battery terminals, check with voltages (from a regulated power supply) of 13.6 V and 12.5 V applied across the battery terminals that the relay switches off and on respectively. The "on" threshold may be corrected by, for instance, connecting a 1N4148 (cathode to +line!) in series with D7. The "off" threshold is ...