The bc548 transistor is working as a switch which will disconnect the ground of the lm317t from the solar cell when the battery become full charge.
Solar panel 12v battery charger circuit diagram.
1n4007 diodes 3nos.
Circuit diagram of solar panel battery charger step 6 from below you can see the soldered connections how they run along the copper tracks.
2k2 1 4 watt resistor 1no.
That looks cool isn t it.
Ic 7812 1no.
One 555 timer ic is used for detecting the voltage level and relay is used to disconnect the ac input.
The schematic shown here is a very effecient automatic solar battery charger circuit which can be used to charge 12v sla batteries from solar cells.
The following solar panel wiring diagram shows that a 12v 120w pv panel is connected to the solar charge controller panel negative terminal of panel to the negative terminal of mppt charge controller and vice versa for positive terminal.
Solar panel 20v 1 amp.
7808 voltage regulator is used for constant supply to the operation of the circuit to cut at a required fixed voltage.
Before delving into the following concepts you can probably try this super easy solar battery charger which will ensure safe and guaranteed charging of a small 12v 7 ah battery through a small solar panel.