This circuit makes it posible to monitor the charging process to a higher level. Final adjustsments are simple and the only thing needed is a digital voltmeter for the necessary accuracy. 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.
|Skema Rangkaian 12 Volt Battery Monitor lm3914|
At 12.65 volt and higher the battery is fully charged, and at 11.89 is considered 'empty'. This circuit, with the components shown, uses less than 10mA. Ofcourse you can adapt this circuit to your own needs by making small modifications. The circuits above is set for 'DOT' mode, meaning only one Led at a time will be lit. If you wish to use the 'BAR' mode, then connect pin 9 to the positive supply rail, but obviously with increased current consumption. The LED brightness can be adjusted up- or down by choosing a different value for the 4K7 resistor connected at pin 6/7.