Circuit diagram of 12V Lead-Acid Battery Monitor.
This easy circuit makes it possible to monitor the charging process to a higher level. Final adjustsments are simple and easy and the only device required is a digital voltmeter for the important accuracy and reliability. Connect an input voltage of 12.65 volt between the positive and negative poles and adjust the 10K trimmer potentiometer until LED 10 lights up. Lower the voltage and in sequence all other LED’s will light up. Check that LED 1 lights up at approximately 11.89 volts.