Displays the current charge status of a 12 V battery in 5 stages with 3 LEDs. This makes it easy to check the battery and prevent deep discharge. It also checks whether the battery is OK and whether it is accepting the full charging voltage from the charger. (If the battery monitor is connected to the battery during the charging process). The battery monitor is designed to monitor a battery in a closed, active circuit. Extremely low self-consumption of less than 4.9 mA!