Automatic Batteray Charger

This circuit basically is consisted of a comparator, that monitors reference tension which permanent. If battery tension exceeds maximum level which has in determining before all, relay would be active and will stop charging current. If battery tension went down under its low threshold value, relay is discharged causing enables reenter charging current.


Comparator formed by operation amplifier IC 741. Power allowance tension for amplifier Opamp stabilized by R8 and D4, so that is not influenced by stress variation of battery. Reference tension for operational amplifier alighted from power allowance is stabilized this through R7 and D3. Reference tension compared to a part of battery tension, what taken away from voltage divider R9/R10/R11.

For tuning of tension at R10 enters don’t tumble operational amplifier will become height, makes Q1 and Q2 on, causing activates relay and breaks current pegisian to battery. This aflame LED indicates that battery has been full loaded. To prevent battery connected returns to admission filling if there is the voltage drop a few, hence some of output tensions of operation amplifier is baited to input don’t tumble through R5 and R6. So thereby the operational amplifier is functioning equal to schmitt.