Blue Sea Systems m-Series Mini Selector Battery Switch, 4 Position, Battery Combine, 300A, 32V DC, IP66

Overview

The Blue Sea Systems m-Series Mini Selector Battery Switch is a 4-position battery switch for boats with two battery banks, letting the operator select bank 1, bank 2, both banks combined, or OFF from one control. It is rated for 32V DC systems, with 300A continuous, 500A intermittent for 5 minutes, and 900A starting for 30 seconds, which makes it a practical fit for outboards and small gasoline or diesel engine installations.

The make-before-break contact layout allows switching between battery banks without interrupting power, while the combine position can bring both banks online when the electrical system calls for it. The switch uses tinned copper terminal studs and accepts 3/8 in or M10 ring terminals, with cable clearance for 4/0 AWG cables.

Key features

• Selector 4-position operation gives the helm or battery compartment a single control for OFF, battery 1, battery 2, and battery combine functions.
• Battery combine capability lets both banks feed the load side when that operating mode is needed.
• Make-before-break contact action helps keep connected loads powered while changing between battery banks.
• 32V DC maximum voltage and 300A continuous rating support common low-voltage DC marine starting and house battery layouts.
• IP66 rating and ignition protection support installation in exposed marine areas and aboard gasoline-powered boats when installed correctly.
• Tinned copper 3/8 in-16 terminal studs accept 3/8 in or M10 ring terminals and help keep high-current connections secure.
• Case accepts surface or rear panel mounting, and #10 mounting screws fit the mounting holes.
• Two battery inputs and 4/0 AWG cable rating give the installer room for a high-current two-bank installation.

Variants

This product is offered in two color configurations. The switch function, ratings, terminal format, and battery combine behavior remain the same across both variants.

The only listed difference is the housing color, so the choice mainly affects how the switch looks in the battery area, electrical panel, cockpit locker, or service compartment.

• 6007, red: Red housing for installations where the battery switch should stand out visually or match a traditional battery disconnect layout.
• 6007200, black: Black housing for panels or compartments where a lower-profile appearance fits better with surrounding electrical equipment.

Installation and fit

This switch is intended for two-bank DC battery systems where the same load side can be fed by either battery bank or by both banks together. It does not include an alternator field disconnect, so alternator protection and switching procedure should be considered as part of the full charging-system layout.

The 3/8 in-16 terminal studs use a 120 in-lb torque value, and the case provides 1.12 in of clearance for 4/0 AWG cable routing. That matters in battery compartments where cable bend radius, lug stack-up, and service access can be tight.

Use cases on board

This switch fits small-boat starting and house-bank layouts where the operator wants manual control over two isolated battery banks and a combine option. It is a good match for center consoles, cruisers, fishing boats, sailboats, and workboats using 12V or 24V battery systems within the switch rating.

The ignition-protected rating is useful for gasoline-powered boats, and the IP66 rating helps when the switch is mounted in lockers, compartments, or areas that may see spray and washdown exposure. Final placement should still allow cable support, strain relief, and clear access to the selector knob.