In-Depth Review of the Blue Sea 7622100 ML-ACR Automatic Charging Relay with Manual Control

Introduction to the Blue Sea 7622100 ML-ACR

The Blue Sea 7622100 ML-ACR is an innovative magnetic latching (bi-stable) automatic charging relay specifically designed for efficient management of dual battery banks in marine environments. Its core function is to seamlessly connect batteries during charging phases and isolate them during discharging or engine startup, ensuring optimal power distribution and preventing unintended drain. Supporting a robust continuous current of 500 amps, this relay is well-suited for high-output alternators commonly found on modern boats and vessels.

What distinguishes this model is its combination of automated operation paired with manual override capabilities. It includes a Remote Control Contura Switch (PN 2146) that enables manual control, offering flexibility for emergency situations, maintenance, or system testing. The relay’s durable Deutsch DTM connector guarantees a secure, corrosion-resistant connection, vital for enduring harsh marine conditions. This comprehensive review explores its technical specifications, standout features, installation procedures, real-world performance, and user feedback, aiding you in determining whether it’s the ideal solution for your marine electrical setup.

Key Features of the Blue Sea 7622100 ML-ACR

This relay is equipped with numerous advanced features tailored for demanding marine applications:

Magnetic Latching Technology

The ML-ACR employs magnetic latching (bi-stable) technology, which minimizes power consumption—drawing less than 40mA during monitoring of terminal voltage in both states. When transitioning between states, it briefly requires a moderate burst of power (less than 7.0A), ensuring energy efficiency. This low power draw is crucial for preserving battery life during extended periods of inactivity, making it ideal for vessels that remain idle for days or weeks.

Automated Battery Management System

This relay intelligently manages two battery banks by automatically connecting them when a charging source, such as an alternator, solar panel, or shore power, is active. Once charging ceases, it isolates the banks, preventing unnecessary discharge. Its dual-sensing technology accurately monitors voltage levels on each battery bank, ensuring proper charging and maintenance:

Dual-Sensing Technology: Ensures both batteries are charged evenly, extending their lifespan.
Start Isolation (SI): Protects sensitive electronics during engine cranking by temporarily disconnecting house loads.
Engine Isolation (EI): Prevents interference between multiple engines, optimizing alternator performance.

Manual Override and Safety Features

The relay comes with a SPDT Remote Control Contura Switch (PN 2146) that allows manual operation:

Emergency battery combining for reliable starts.
Lock-off mode for safe maintenance procedures.
LED indicators provide real-time system status updates (combined, isolated, voltage lockout, start/engine isolation).

Dual Sensing for Balanced Charging

The ML-ACR’s capacity to sense voltage on both battery banks ensures balanced charging, reducing the risk of overcharging or undercharging either bank. This feature extends battery longevity and enhances overall system efficiency.

High Current Capacity

Supporting a 500A continuous rating, with 700A for 5 minutes and a cranking capacity of 1450A for 30 seconds, this relay is built for high-demand marine applications. Its silver alloy contacts guarantee reliable switching at high currents.

Visual Status Indicators

An integrated LED (or optional LED indicators via the Contura Switch) displays system status, such as whether batteries are combined, isolated, or in a lockout state, providing quick visual confirmation for operators.

Rugged and Compact Design

Constructed with durable materials, it features 3/8” tin-plated copper studs for maximum conductivity and corrosion resistance. Its compact dimensions (3.75” W x 5.47” H x 2.03” D) and weight (2.06 lb) make installation flexible. The relay supports 4/0 AWG cables and is mounted using #10 hardware.

Technical Specifications

This relay is optimized for 12V DC systems, with key specifications including:

Nominal Voltage: 12V DC
Continuous Rating: 500A
Intermittent Rating (5 min): 700A
Cranking Rating (30 sec): 1450A
Control Circuit Connection: Deutsch DTM
Manual Control: Yes
Start and Engine Isolation: Yes
Terminal Stud Size: 3/8” – 16 (M10)
Weight: 2.06 lb
Dimensions: 3.75” W x 5.47” H x 2.03” D
Regulatory Compliance: CE Marked, IP66, ISO 8846, SAE J1428

Installation and Setup Guidelines

Installing the ML-ACR is a straightforward process, supported by comprehensive documentation and clear wiring diagrams. Follow these steps for optimal setup:

1. Preparation

Verify system compatibility with 12V DC and high-current capacity requirements.
Gather necessary tools like torque wrenches, screwdrivers, crimpers, and marine-grade cables (preferably 4/0 AWG).
Review the included wiring diagrams and instructions carefully.

2. Mounting

Choose a dry, ventilated location away from heat sources or water exposure.
Secure the relay with #10 screws through mounting holes.
Ensure sufficient airflow to operate within the specified temperature range.

3. Wiring

Connect battery banks to the 3/8” studs using 4/0 AWG cables, tightening to 140 in-lb (15.82 Nm).
Use the Deutsch DTM connector for control wiring, following the wiring diagram for proper connections to the Contura Switch and optional LED indicators.
Properly ground the system to prevent electrical faults.

4. Testing

Power on the system and verify automatic switching thresholds with a multimeter (e.g., 13.5V for connecting, 12.75V for opening).
Test manual control by toggling the Contura Switch to confirm battery combining and isolation functions.
Check LED indicators to ensure accurate status display.

5. Final Checks

Inspect all connections for tightness and insulation integrity.
Label circuits clearly for future reference.
Test start and engine isolation features if configured, for operational safety.

Consult the dedicated ML-ACR Troubleshooting Guide for resolving common issues such as improper switching or LED malfunction. Blue Sea Systems offers additional online resources, including instructional videos and technical articles, to support installation and operation.

Real-World Performance and Applications

The ML-ACR has proven its worth in various marine environments, thanks to its high current capacity and smart management features. Its 500A continuous load support ensures efficient charging of multiple batteries, even with high-output alternators. The magnetic latching design reduces power draw, making it suitable for vessels that spend long durations idle without draining batteries.

When used in conjunction with the Blue Sea ML-RBS (Remote Battery Switch), it forms part of a comprehensive battery management system that allows for automatic sharing of charge and remote control of battery banks, ideal for larger vessels with complex electrical needs. It also effectively isolates batteries during engine start, protecting electronics from voltage surges, and ensures batteries are maintained at optimal levels through dual sensing.

User Feedback and Ratings

Customers highly regard the Blue Sea 7622100 ML-ACR, awarding it an average rating of 4.7 out of 5. Reviews highlight its reliability, ease of installation, and durability in saltwater conditions. Many users appreciate the manual override feature and LED indicators, which provide quick system status updates. Some feedback points include:

Reliability: Consistent operation over years with no failures reported.
Ease of Use: Clear instructions and intuitive manual controls.
Durability: Corrosion-resistant studs and IP66 rating ensure longevity in marine environments.
Efficiency: Low power consumption preserves battery life during extended trips.

Constructive comments mention the higher initial cost compared to basic relays, though users agree that the advanced features justify the expense. Some wish for the LED indicator to be included rather than optional and note that wiring can be complex for beginners without professional help.

Comparison with Other ML-ACR Models

Blue Sea Systems offers a range of ML-ACR variants to suit diverse needs. Here’s a comparison of the 7622100 with other models:

Model	Control Circuit	Manual Control	Distinctive Features
7620	Tinned Wire	Yes	Basic model with straightforward wiring
7620100	Deutsch DTM / Amphenol ATM	Yes	Includes Deutsch/Amphenol connectors
7621	Tinned Wire	No	No manual control option
7621100	Deutsch DTM / Amphenol ATM	No	Dual sensing, no manual control
7622	Tinned Wire	Yes	Includes Contura Switch
7622100	Deutsch DTM	Yes	Deutsch connector, manual override included
7623	Tinned Wire	Yes	Designed for 24V systems
7623100	Deutsch DTM / Amphenol ATM	Yes	24V with Deutsch/Amphenol connectors

The 7622100 model strikes a balance by offering a secure Deutsch DTM connector, manual control, and high current capacity, making it suitable for demanding marine applications requiring reliable dual battery management.

Pricing, Availability, and Support

MSRP: $332.84
Typical Retail Price: Around $281.99, varying by retailer
Where to Purchase: Available through authorized dealers like West Marine, Hodges Marine, and online stores. Visit Blue Sea Systems’ official website for a dealer locator and authorized sellers.
Payment Options: Some retailers provide financing options, including Affirm, for orders exceeding $50.
Warranty: Comes with a lifetime warranty, ensuring long-term reliability and peace of mind.

Seamless Integration with Battery Management Ecosystem

The ML-ACR integrates effortlessly with the Blue Sea ML-RBS (Remote Battery Switch), enabling a comprehensive and automated battery management system. This setup allows vessel operators to:

Automatically share alternator charge between the main and auxiliary batteries.
Operate remote switches for battery combining or isolating functions.
Expand control with the optional ML Series Link Bus (PN 9160) for centralized remote management.

This integrated approach is especially beneficial for larger boats with extensive electrical demands, simplifying management and enhancing safety.

Safety, Certifications, and Compliance

The Blue Sea 7622100 ML-ACR adheres to rigorous safety standards and certifications, including:

CE Marked: Meets European safety directives.
IP66 Rating: Resistance to powerful water jets and dust, suitable for marine environments.
ISO 8846: Compliant with ignition protection standards.
SAE J1428: Meets industry standards for marine electrical components.

It also includes a California Proposition 65 warning related to certain chemicals, emphasizing safe handling and installation practices.

Why Opt for the Blue Sea 7622100 ML-ACR?

Versatility: Ideal for various marine vessels, including recreational boats, fishing boats, and liveaboards.
Durability: Built with corrosion-resistant materials and backed by a lifetime warranty.
User-Friendly Design: Features manual control, clear LED indicators, and straightforward installation.
Energy Conservation: Magnetic latching minimizes power consumption, critical for long voyages.
Enhanced Safety: Start and engine isolation features protect sensitive electronics and improve operational safety.

Whether upgrading an existing system or installing anew, this relay provides unparalleled control and dependability for your marine electrical needs.

Final Thoughts: Is It the Right Choice?

Advantages:

High Amp Support: 500A continuous capacity, leading in its class.
Low Power Usage: Magnetic latching technology conserves energy.
Manual Control: Emergency battery combining and system override.
Dual Sensing: Ensures balanced and efficient charging.

Disadvantages:

Price: Higher initial investment compared to basic relays.
Additional Wiring: Optional LED indicators require extra wiring efforts.

Who Should Consider Buying?

Boat Owners: Managing dual battery banks for reliability and safety.
RV Enthusiasts: Need for dependable off-grid power management.
High-Power System Users: Running alternators with outputs exceeding 300A.

Alternative Options

Blue Sea SI-ACR: A more affordable, basic model without manual control.
Victron Cyrix Li: Focused on lithium battery systems, with lower current ratings.

Conclusion

The Blue Sea 7622100 ML-ACR Automatic Charging Relay with Manual Control stands out as a top-tier component for marine electrical management. It combines advanced features like dual sensing, manual override, and high current capability with durable construction and easy installation. Customers consistently rate it highly for its reliability, ease of use, and longevity in demanding marine environments. Priced at approximately $281.99 (MSRP $332.84), it’s a worthwhile investment for serious boaters seeking dependable power management and enhanced safety. Whether for coastal cruising, long voyages, or professional marine operations, upgrading to the ML-ACR ensures your batteries are optimally charged, electronics are protected, and your vessel is always ready for the next adventure.

Visit https://x.ai/api for API services and advanced integration options. For purchasing or authorized installation, consult Blue Sea Systems’ official website or trusted marine retailers. Enjoy safe and reliable boating with the confidence that comes from high-quality electrical management systems.