Blue Sea Systems m-Series Automatic Charging Relay, 12/24V DC, 65A, Start Isolation

Overview

The Blue Sea Systems 7601 is a compact m-Series automatic charging relay for 12V and 24V DC systems that manages charging between two battery banks with a 65A continuous rating and a 115A intermittent rating for 5 minutes.

It combines batteries while a charge source is present and separates them when charging stops, so a start battery and a house bank can charge from one alternator without staying tied together at rest. This model is dual sensing, which means it can react to charging on either battery bank, and it includes Start Isolation to keep house loads off the engine circuit during cranking.

For fit and wiring checks, the relay uses 1/4 in.-20 studs, accepts cable up to 1/0 AWG, and calls for 6 AWG cable to meet its current rating. The housing is rated IP67 for temporary immersion, and the unit is ignition protected for use on gasoline-powered boats when installed correctly.

Key features

• Handles charging current from alternators up to 65A on many outboard and smaller inboard charging systems
• Works with both 12V and 24V DC battery setups
• Dual-sensing operation monitors charging on either battery bank
• Start Isolation input separates the house side during engine cranking to reduce voltage drop and spikes at sensitive electronics
• IP67-rated housing and ignition protection suit the wet, vibration-heavy conditions found on board
• Compact body can be surface mounted, rear mounted, or panel mounted where space is limited
• LED status indicator and snap-on insulating cover make it easier to check operation and protect terminal connections
• 1/4 in.-20 studs with support for cable up to 1/0 AWG

Installation and setup

This relay fits boats with separate start and house batteries that need automatic charging management without manual switching every time the engine runs. It makes sense on single-engine outboards, skiffs, center consoles, and similar two-bank layouts where the alternator output stays within the 65A rating.

It is not intended to carry engine starting current. If the system may need emergency battery paralleling for starting, that function should be handled by a battery switch or another device built for that purpose. For longer service life, mount the relay in a dry, protected location and avoid placing it directly above battery banks.

The minimum setup uses one positive connection from each battery bank and a ground lead. The ground connection is fused at 1A, and the optional Start Isolation lead uses a fused 1A to 10A connection to the cranking circuit.

Compatibility and fit

This is a good match for boaters who want both battery banks to charge automatically from a single charging source while keeping the start battery isolated when the engine is off. It also suits installations where electronics on the house side benefit from temporary isolation during cranking.

Before ordering, check alternator output, available mounting space, cable size, and whether the boat uses a two-bank system. Installations with larger alternators, higher charging loads, or battery banks that are routinely paralleled for starting may need a higher-capacity ACR.

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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