Blue Sea Systems M2 DC Voltmeter

The Blue Sea Systems M2 DC Voltmeter monitors the voltage of up to four separate battery banks on one bright, auto-dimming OLED display, so you can check a house bank, a start battery, and additional banks all from a single panel instead of installing and wiring a separate meter for each one.

Key features

• Monitors voltage from 8-70V across up to 4 battery banks
• Auto-dimming OLED display, easy to read in bright sun or full darkness
• 80dB adjustable alarm for high or low voltage
• Isolated MOSFET relay for external circuit control based on any measured value
• IP66 rated gasket creates a waterproof seal on the unit face

This is a simpler, voltage-only counterpart to the M2 DC Multimeter with SoC (PN 1830) — if tracking current draw and state of charge isn't needed and straightforward voltage monitoring across several banks is the priority, this meter covers that at a lower cost, lighter weight, and smaller footprint than the full multimeter version.

The adjustable alarm is a genuinely useful early-warning feature: set a low-voltage threshold and the meter sounds before a battery drops low enough to risk starting problems or a shortened battery life from repeated deep discharge over successive charge cycles.

Because it monitors four banks from one compact unit, it's a practical fit for larger boats with separate house, start, generator, and thruster batteries, where running four individual meters would eat up far more panel space than this single display needs, while keeping wiring and installation considerably simpler overall.