Charge controller circuit diagram capable of automatic power off

Photocoupler

Charge controller circuit capable of automatic power off

The charging circuit consists of a 12V DC power supply, a current limiting resistor R6, a relay contact, an isolation diode VD2, and a working indicator circuit LED. When charging, press button SB first, relay K energizes and pulls in, relay contact turns charging circuit on, charging starts, LED lights indicate. NE555 and R1, R2 and C1 form an ultra low frequency pulse oscillator.
The timing divider circuit consists of a 14-bit binary serial counter/divider CD4020. The CD4020 contains 14 binary counters, which are connected in series. The time base pulse is input from the tenth pin and output from the third pin. C3 and R4 form the reset circuit of IC2. When the power is turned on, the reset pulse generated by C3 and R4 first resets the frequency divider. When the timing time is reached, the third pin of the CD4020 outputs a high level, and the relay drive tube VT is turned off. The relay release disconnects the charging circuit.