Multiple Battery Bank Monitor Minder Low Voltage Discharge Alarm 12 Volt Marine RV #BTM21/22/23

Regular price $24.95

Tax included.

Monitor your battery or battery bank(s) for a low voltage discharge condition.

For one, two or three battery banks. Individual voltmeters have on / off switch. Attaches to your battery.

Fully wired 12 volt battery monitor panel. Alarms when battery voltage drops to the minimum voltage level, when the battery / bank must be charged. The Built in voltmeter indicates the voltage level. The built in high pitch tonal alarm and blinking warning LED alerts you to the low battery condition. A switch on the voltmeter allows the display to be switched off while allowing the alarm to monitor the voltage. #BTM21, 22, 23.

The panel monitors your battery when the voltage drops to 12.0 volts the alarm sounds indicating the need to charge your battery. Permanent damage is done to the battery in the low discharge state. Allowing the battery to discharge beyond the 50% level reduces the life of the battery.

This pre-wired assembly consists of a built in battery voltage monitoring circuit board with a built in tonal alarm and blinking red indicator, a high quality voltmeter for checking the voltage level of your battery,  and a switch to control the voltmeter. Attaches directly to battery, one conection per battery.


The meters have easy to read red LED segments (blue available upon request) and connect to your 12 volt battery. The meter front is splash proof. The meter  range to 35 vdc.

Alarm Monitor

High db notification tonal alarm with a bright blinking LED. Trips at 12.0 V.


The switch turns power off to the voltmeter. while allowing the alarm to monior.

Mounting and installation

The mounting plate allows the assembly to be mounted in a panel of any thickness the panel hole size is 3-14" square. Depth required 2-1/2"'

#BTM21 One battery or  bank Monitor.

#BTM22 Two Bank Monitor/ second battery.

#BTM23 Three bank Monitor/ third battery.


-Working Voltage: DC 10-16 Volts +/- 10%

- Monitor trip voltage 12.0 volt +/- 10%, factory adjustable 10-14 volts. 20 microamps monitor, 10 ma. when alarm sounds.

-Polarized male 0.250 stud disconnect crimp terminals.

- Alarm:

Piezoelectric 3900 +/- 500 Hz

Sound volume: 80 db

Sound type: intermittent one second on/off

 LED Brightness: 5000 mcd