You can use this board to check voltage level ( 8 Level check ) , without external supply needed. You connect board to battery, you will get how much voltage , display by 8 LED

Technical information:
 # No Supply Needed to the circuit ( Use the power from battery directly )
 # 8 LED indicator ( 3 Green / 3 Yellow / 2 Red )
 # 8 POT to adjust reference voltage to get high accuracy
 # LED will show voltage ( 10.5V / 11.0V / 11.5V / 11.8V / 12.0V /12.5V / 12.8V /13.8V )
 # Diode protection to prevent wrong connection to battery
 # Current consume 56 mA
 # PCB size : 3.79" x 2.47"

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