The BM-LOW model with a box was selected to operate as a 12V lead-acid battery voltage monitor. The different LED colors gives it an easy indication of the battery status. The meter can be connected continuously or with a switch for temporarily checking the status.

The meter is set for a no load voltage. The minimum voltage is 12V and the maximum is 13.8V. Extra labels are added at 12.0V for "LOW", 13.2V for "FULL" and 13.8V for "CHARGING".

Figure 1. 12V Lead-acid battery in charging stage

Figure 2. 12V Marine battery

Figure 3. Close up of display