12 Volt LED Lead Acid Battery MeterIn the circuit, a cloister voltage comparator (LM339) is acclimated as a simple bar blueprint beat to announce the allegation action of a 12 volt, advance acerbic battery. A 5 volt advertence voltage is affiliated to anniversary of the (+) inputs of the four comparators and the (-) inputs are affiliated to alternating credibility forth a voltage divider. The LEDs will brighten back the voltage at the abrogating (-) ascribe exceeds the advertence voltage.
Calibration can be done by adjusting the 2K potentiometer so that all four LEDs brighten back the array voltage is 12.7 volts, advertence abounding allegation with no amount on the battery. At 11.7 volts, the LEDs should be off advertence a asleep battery. Anniversary LED represents an almost 25% change in allegation action or 300 millivolts, so that 3 LEDs announce 75%, 2 LEDs announce 50%, etc. The absolute voltages will depend on temperature altitude and array type, wet cell, gel corpuscle etc. Additional advice on array aliment can be begin at:
Calibration can be done by adjusting the 2K potentiometer so that all four LEDs brighten back the array voltage is 12.7 volts, advertence abounding allegation with no amount on the battery. At 11.7 volts, the LEDs should be off advertence a asleep battery. Anniversary LED represents an almost 25% change in allegation action or 300 millivolts, so that 3 LEDs announce 75%, 2 LEDs announce 50%, etc. The absolute voltages will depend on temperature altitude and array type, wet cell, gel corpuscle etc. Additional advice on array aliment can be begin at:
