This is a 12V battery checker circuit that uses 3 LEDs that light up at their respective voltages. The red LED lights up when the battery voltage is between 8 to 10V, the orange one at voltages between 10. 5V to 12V and the green one when the battery voltage is above 12. 5V. This is a tried and tested battery checker circuit using one NPN and one PNP
transistor. A PCB is given along with the schematic.