Blue Sea Systems m-Series Single Circuit ON-OFF Battery Switch, Locking Key, 48V DC, 300A Continuous, IP66, 3/8 in Studs

Overview

The Blue Sea Systems m-Series Mini Battery Switch is a single-circuit ON-OFF battery switch with a locking key for controlling one battery feeding one load group on board. It is rated for 48V DC systems, with a 300A continuous rating, 500A intermittent rating, and 900A starting rating for 30 seconds, making it a practical fit for many outboard and small gasoline or diesel engine installations.

The switch uses tin-plated copper studs that accept 3/8" (M10) ring terminals, with a 7/8" (22 mm) stud length to help accommodate multiple cable terminals where the installation allows. An isolating rear cover protects the contacts, while breakout tabs let cables enter from different directions for cleaner routing in compact battery compartments, helm panels, or equipment lockers.

Key features

• Single Circuit ON-OFF switching for one battery connected to one load group.
• 300A continuous rating with 900A starting capacity for 30 seconds.
• Maximum voltage rating of 48V DC for common low-voltage marine electrical systems.
• Tin-plated copper studs help maintain conductivity and resist corrosion in damp marine spaces.
• 3/8" (M10) studs work with standard heavy-duty marine battery cable ring terminals.
• Locking key operation helps limit accidental or unauthorized switching.
• IP66 rating supports use in areas exposed to spray and washdown.
• Ignition protected and rated to ISO 8846, SAE J1171, UL 1107, and UL 1500.

Variants

This switch is offered in two color configurations. Both variants use the same single-circuit ON-OFF layout with a locking key, the same 48V DC maximum voltage rating, and the same current ratings.

The color change affects how the switch presents on the boat and how easily it matches nearby panels, battery labels, or existing Blue Sea Systems electrical hardware.

• 6004: Red. The red version gives the battery control point a traditional high-visibility look, which can help it stand out in a battery compartment or behind an access panel.
• 6004200: Black. The black version has a more subdued appearance for helm panels, equipment lockers, or installations where the switch needs to blend with surrounding hardware.

Installation and fit

The compact m-Series form factor works well where space is limited but the battery switch still needs to handle engine starting loads. The case supports surface, front panel, or rear panel mounting, so it can be fitted to a bulkhead, panel face, or protected enclosure depending on the layout of the boat.

Use properly sized marine battery cable and ring terminals for the load being carried. The 3/8" terminal studs should be torqued to 120 in-lb (13.56 Nm), and the rear cover should be positioned so the live contacts remain protected after installation.

Electrical and marine use

This is a manual battery isolation switch for straightforward ON-OFF control, not a battery combiner or selector switch. It is a good match for boats that need a clear way to disconnect one starting or house battery feed when leaving the vessel, working on the electrical system, or shutting down nonessential loads at the dock.

The IP66 rating, ignition protection, tin-plated copper studs, and stainless flange nuts make it suitable for the kind of damp, vibrating, and corrosion-prone spaces found on small powerboats, tenders, fishing boats, and compact cruising boats.

Orders are processed within 2 business days, which includes verification, packing, and dispatch. Orders of $100 or more qualify for free shipping when eligible. For orders under $100, shipping costs are calculated at checkout based on destination, package weight, and selected service. International shipping is available for eligible products, and certain items may require additional handling, warehouse transfers, or may ship directly from the manufacturer, which can affect processing time.

Deliveries are handled by preferred carriers such as USPS, UPS, FedEx, DHL, and others depending on your location and selected service. Estimated delivery times are displayed at checkout and may vary due to customs processing, carrier delays, weather, postal disruptions, or other circumstances beyond our control. Once your order ships, you'll receive a confirmation email with tracking information. Tracking may take up to 24 hours to update on the carrier's website and is also available through your account when applicable.

We ship throughout the United States and to most international destinations for products eligible for international shipping. International orders may be subject to customs duties, taxes, brokerage charges, or other import fees, which are the customer's responsibility and are not included in the product or shipping price. PO Boxes are accepted only when shipping through USPS, and not all packages qualify for this option. If your order does not arrive within the estimated delivery window, please contact us at info@apollolighting.com or +1 (954) 375-0100 so we can assist with locating your package.

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Returns may be requested within 30 days of receiving your order. Items must be unused, uninstalled, unaltered, and returned in their original packaging with all tags, packing materials, blank warranty cards, manuals, instructions, accessories, and included items. Certain products, including installed or used electronics, electrical components, lighting, consumables, custom or special-order items, cut-to-length products, safety equipment, and merchandise exposed to water or marine conditions, may not be eligible for return.

To request a return, sign in to your account and select the applicable order and items, and submit your request for review. Eligible unfulfilled items may also be submitted for cancellation within 1 hour of placing the order. Returns or cancellations are not considered approved until you receive confirmation from Apollo Lighting. Please do not ship or drop off merchandise before receiving return approval and instructions.

Customers are responsible for arranging and paying for return shipping unless the return is due to an error by Apollo Lighting or the item is verified as defective, damaged, or incorrect. Missing, damaged, defective, or incorrect items must be reported within 2 business days of delivery, and photos or other documentation may be required for review. If the issue is verified, Apollo Lighting may provide or reimburse return shipping and issue a replacement or refund depending on the circumstances. International customers are responsible for return shipping, duties, taxes, customs charges, brokerage fees, and other costs associated with an international return.

After your return is received and inspected, approved refunds are issued to the original payment method and may take 5-7 business days to appear after processing. Original shipping and handling charges are nonrefundable, and the value of any included free items that are not returned may be deducted from the refund. Apollo Lighting does not charge a standard restocking fee on eligible returns. Returns that are incomplete, damaged, installed, used, altered, improperly packaged, or otherwise do not meet the eligibility requirements may be refused. We recommend using a trackable and appropriately insured shipping service for all customer-arranged returns.

For assistance, contact info@apollolighting.com or call +1 (954) 375-0100.

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Many products sold by Apollo Lighting include a manufacturer's warranty covering defects in materials or workmanship. Warranty terms vary by brand, product category, and model, so eligibility, coverage duration, exclusions, and available remedies are determined by the applicable manufacturer. We recommend reviewing the warranty information provided with your product before installation or use, especially for marine electronics, navigation equipment, lighting, electrical systems, pumps, safety equipment, and other specialized marine products.

If you need warranty service, the claim must follow the process established by the manufacturer, authorized service center, or designated warranty provider. You may be asked for proof of purchase, a serial number, product registration, photos, maintenance or installation records, or other documentation. Apollo Lighting does not determine or modify a manufacturer's warranty coverage or final claim decision, but we are happy to help provide purchase information and direct you to the appropriate manufacturer or warranty resource.

Keep your receipt, product documentation, serial number information, and original packaging when practical. Damage caused by normal wear, misuse, improper installation, insufficient maintenance, corrosion, impact, unauthorized modifications, electrical issues, or operation outside the manufacturer's specifications may not be covered. Warranty claims are separate from standard returns, so a product that has been installed, used, or exposed to marine conditions may no longer qualify for return while still remaining eligible for evaluation under the manufacturer's applicable warranty.

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