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Battery Status Monitor (BSM)

Battery Status Monitor


The Battery Status Monitor (BSM) is a limited range Light Emitting Diode (LED) voltmeter, designed to monitor the voltage across a 6V or 12V lead-acid battery in an automotive situation.

The BSM is protected against electrical abuse including reverse connection and unlike an analogue meter it is immune to vibration. The digital BSM has built in ambient light detection, which reduces the LED brightness under low light (night driving) conditions.

Alternative Versions

There are a number of different electrical types and mounting options for the BSM, ensure you have the correct version for your application. The BSM can be fitted to an instrument panel using the bezel version or be clipped to a tube using the handlebar version. Electrical versions are available for conventional 6V and 12V systems. A further version is available for 12V 'Pre-charged' applications where the battery is initially charged and then discharged in use; such systems are used on some racing machines, caravans and gliders.


Conventional Charging System

Colour 6V Version 12V Version Meaning
Slow Flash RED Less than 5.38V Less than 10.75V Extreme under voltage - recharge battery now!
RED Less than 6V Less than 12V Battery low or under load (engine off).
6.0V to 6.9V
12.0V to 13.8V
Expect Orange / Yellow for a fully charged battery
(engine off).
GREEN More than 6.9V More than 13.8V Battery on charge.
Fast Flash RED More than 7.63V More than 15.25V Over charging, check regulator!

Pre-charged battery system

Colour Voltage Meaning
Slow Flash RED Less than 10.5V Extreme under voltage - recharge battery immediately!
RED Less than 10.5V Capacity nearly exhausted.
10.5V to 12.5V
GREEN More than 12.5V Fully charged (at rest)
Flashing GREEN More than 13.8V Battery on charge.
Fast Flash RED More than 15.25V Over-charging - investigate!