Marine electrical systems demand precision, reliability, and safety to ensure seamless operation on the water. The Blue Sea 7622100 ML-ACR Automatic Charging Relay with Manual Control stands out as a robust solution for managing battery banks in boats and other marine applications. Designed to automatically combine batteries during charging and isolate them during discharging or engine starting, this 12V 500A relay offers advanced features like manual override, dual sensing, and low power consumption. This article provides an in-depth exploration of the Blue Sea 7622100 ML-ACR, covering its features, specifications, installation, performance, user feedback, and why it’s a top choice for marine enthusiasts.
Introduction to the Blue Sea 7622100 ML-ACR
The Blue Sea 7622100 ML-ACR is a magnetic latching (bi-stable) automatic charging relay engineered to manage two large battery banks efficiently. Its primary function is to connect batteries during charging to ensure both banks receive adequate power while isolating them when the engine starts or during discharge to prevent unintended power drain. With a continuous rating of 500 amps, it supports high-output alternators, making it ideal for boats with complex electrical systems.
What sets this relay apart is its combination of automation and manual control. The included Remote Control Contura Switch (PN 2146) allows users to override automatic functions, providing flexibility for emergency situations or maintenance. The relay’s Deutsch DTM connector ensures secure, corrosion-resistant connections, enhancing durability in harsh marine environments.
This review delves into the relay’s technical specifications, key features, installation process, real-world performance, and user experiences to help you determine if it’s the right fit for your vessel.
Key Features of the Blue Sea 7622100 ML-ACR
The Blue Sea 7622100 ML-ACR is packed with features that cater to the needs of marine electrical systems. Below are the standout aspects that make it a preferred choice:
1. Magnetic Latching Technology
The ML-ACR uses a magnetic latching (bi-stable) relay, which consumes minimal power—less than 40mA to monitor terminal voltage in both ON and OFF states. When changing states, it draws a moderate current for a brief period (<7.0A), ensuring energy efficiency. This low power draw is critical for preserving battery life, especially during extended periods of inactivity.
2. Automatic Battery Management
The ML-ACR intelligently combines two battery banks when a charging source (alternator, solar, or shore power) is detected. Once charging stops, it isolates the batteries to prevent discharge.
- Dual-Sensing Technology – Monitors voltage on both batteries for accurate charging.
- Start Isolation (SI) – Temporarily disconnects house loads during engine cranking to protect sensitive electronics.
- Engine Isolation (EI) – Isolates two running engines to prevent alternator interference.
3. Manual Control with Safety Features
ncluded SPDT Remote Control Contura Switch (PN 2146) allows:
- Manual combining for emergency starts.
- Lock-off mode for maintenance safety.
- LED indicators show relay status (combined/isolated).
4. Dual Sensing Capability
The ML-ACR senses charging activity on both battery banks, ensuring balanced charging. This dual sensing eliminates the risk of one bank being over- or under-charged, prolonging battery life and optimizing performance.
5. Start and Engine Isolation
- Start Isolation (SI): Configurable to temporarily isolate house loads from the engine circuit during cranking, protecting sensitive electronics from voltage spikes.
- Engine Isolation (EI): Isolates two engines when both are running, safeguarding engine electronics and maximizing alternator output.
6. High Amperage Capacity
With a 500A continuous rating, 700A intermittent rating (5 minutes), and 1450A cranking rating (30 seconds), the relay supports high-output alternators and heavy loads, making it suitable for demanding marine applications.
- 500A continuous rating (700A intermittent for 5 minutes).
- 1450A cranking rating (30 sec) for emergency starts.
- Silver alloy contacts ensure reliable high-current switching.
7. LED Status Indicator
The relay features an LED output (requires optional LED or the included Contura Switch with integrated LED) to indicate whether batteries are combined, isolated, in voltage lockout, or in start/engine isolation. This visual feedback enhances user awareness of the system’s status.
8. Robust Construction
- 3/8″-16 tin-plated copper studs ensure maximum conductivity and corrosion resistance.
- 7/8″ (22mm) stud length accommodates multiple cable terminals.
- Silver alloy contacts provide high reliability for switching live loads, rated for 100,000 switching cycles.
- IP66 rating ensures protection against water and dust ingress, ideal for marine environments.
9. Compact and Versatile Design
Measuring 3.75″ W x 5.47″ H x 2.03″ D and weighing 2.06 lb (0.93 kg), the ML-ACR is compact yet powerful. It supports 4/0 AWG x 2 cables to meet its high amperage ratings, and its #10 mounting allows flexible installation.
Technical Specifications
The Blue Sea 7622100 ML-ACR is designed for 12V DC systems with the following specifications:
| Specification | Details |
|---|---|
| Nominal Voltage | 12V DC |
| Continuous Rating | 500A |
| Intermittent Rating (5 min) | 700A |
| Cranking Rating (30 sec) | 1450A DC |
| Amperage Operating Current | 13mA |
| Amperage When Changing State | <7.0A |
| Live Current Switching | 300A @ 12V DC |
| Switching Cycles | 100,000 |
| Control Circuit Connection | Deutsch DTM |
| Manual Control | Yes |
| Start Isolation | Yes |
| Engine Isolation | Yes |
| Start Assist | Yes |
| Terminal Stud Size | 3/8″ – 16 (M10) |
| Terminal Stud Length | 0.875″ (22.23 mm) |
| Terminal Ring Diameter Clearance | 1.18″ (29.97 mm) |
| Terminal Stud Torque | 140 in-lb (15.82 Nm) |
| Cable Size | 4/0 AWG x 2 |
| Wire Size (Control Circuit) | 20 AWG |
| Minimum Operating Temperature | -10°C |
| Maximum Operating Temperature | 60°C |
| Mounting | #10 |
| Weight | 2.06 lb (0.93 kg) |
| Dimensions | 3.75″ W x 5.47″ H x 2.03″ D |
| Regulatory Specifications | CE Marked, IP66, ISO 8846, SAE J1428 |
Relay Contact Positions
| State | Voltage |
|---|---|
| Combine (30 sec) | 13.5V |
| Combine (90 sec) | 13.0V |
| Open (10 sec) | 12.35V |
| Open (30 sec) | 12.75V |
| Open High | 16.2V |
Included Accessories
- 1 x SPDT Remote Control Contura Switch (PN 2146): ON-OFF-ON switch for manual control.
Optional Accessories
- Remote Control Panel (PN 1147)
- 360 Panel Blank ML-Contura Switch (PN 1520)
- ML Series Link Bus (PN 9160)
Installation and Setup
Installing the Blue Sea 7622100 ML-ACR is straightforward, thanks to its user-friendly design and comprehensive documentation. Below is a step-by-step guide to ensure proper setup:
1. Preparation
- Verify Compatibility: Confirm that your system operates at 12V DC and that your battery banks and alternator are compatible with a 500A relay.
- Gather Tools: You’ll need a torque wrench, screwdrivers, wire cutters, crimping tools, and marine-grade cables (4/0 AWG x 2 recommended).
- Review Documentation: Refer to the included Wiring Diagram, Instructions, and Dimension Drawing for guidance.
2. Mounting
- Select a dry, accessible location away from heat sources and water exposure.
- Secure the relay using #10 screws through the mounting holes.
- Ensure proper ventilation to maintain operation within the -10°C to 60°C temperature range.
3. Wiring
- Battery Connections: Connect the battery banks to the 3/8″-16 tin-plated copper studs using 4/0 AWG cables. Torque to 140 in-lb (15.82 Nm) for secure connections.
- Control Circuit: Use the Deutsch DTM connector for control wiring (20 AWG). Follow the wiring diagram to connect the Contura Switch and optional LED.
- Grounding: Ensure proper grounding to prevent electrical faults.
4. Testing
- Power on the system and verify automatic operation using a multimeter to check voltage thresholds (e.g., 13.5V for combining, 12.75V for opening).
- Test manual override by toggling the Contura Switch to combine or isolate batteries.
- Confirm LED indicators (if installed) reflect the relay’s status.
5. Final Checks
- Inspect all connections for tightness and insulation.
- Label circuits using the label recesses for easy identification.
- Test start and engine isolation features if configured.
The ML-ACR Troubleshooting Guide is a valuable resource for resolving issues like improper switching or LED malfunctions. Blue Sea Systems also provides online resources, including videos and articles, to assist with installation.
Performance in Real-World Applications
The Blue Sea 7622100 ML-ACR excels in managing complex marine electrical systems. Its 500A continuous rating supports high-output alternators, ensuring efficient charging across two battery banks. The magnetic latching technology minimizes power consumption, making it ideal for boats that remain idle for extended periods. The relay’s ability to isolate batteries during engine cranking protects sensitive electronics, such as GPS units and fishfinders, from voltage spikes.
In emergency scenarios, the manual override feature allows users to parallel batteries for starting, a lifesaver when the start battery is depleted. The dual sensing capability ensures balanced charging, extending battery life and reducing maintenance costs. The IP66 rating and corrosion-resistant materials make it reliable in saltwater environments, where exposure to moisture is a constant challenge.
User Reviews and Feedback
The Blue Sea 7622100 ML-ACR has earned high praise from marine enthusiasts, with an average rating of 4.7 out of 5 based on customer feedback. Below are summarized user experiences:
Positive Feedback
- Reliability: Users commend the relay’s consistent performance in managing dual battery banks, with no reported failures even after years of use.
- Ease of Installation: Boaters appreciate the clear instructions and compact design, which simplify integration into existing systems.
- Manual Control: The Contura Switch is a favorite for its intuitive operation and ability to lock off the system during maintenance.
- Durability: The corrosion-resistant studs and IP66 rating ensure longevity in harsh marine conditions.
- Energy Efficiency: The low power draw (<40mA) is a significant advantage for preserving battery charge during long trips.
Constructive Criticism
- Price Point: Some users note that the MSRP of $332.84 (retail price around $281.99) is higher than basic relays, though they acknowledge the value of advanced features.
- LED Requirement: A few users wish the LED indicator was included rather than requiring an optional purchase (though the Contura Switch has an integrated LED).
- Complex Wiring for Novices: While documentation is thorough, beginners occasionally find the wiring process intimidating without professional assistance.
Sample User Testimonials
- John M., Recreational Boater: “The ML-ACR transformed my boat’s electrical system. I no longer worry about my house battery draining during long trips, and the manual switch saved me when my start battery died mid-journey.”
- Sarah T., Liveaboard Sailor: “Installation was a breeze, and the relay’s been rock-solid for two years. The Deutsch connector feels bulletproof, even in salty air.”
- Mike R., Fishing Charter Operator: “Expensive upfront, but worth every penny. My electronics stay protected, and the dual sensing keeps both batteries in top shape.”
Comparison with Other ML-ACR Models
Blue Sea Systems offers several ML-ACR variants to suit different needs. Here’s how the 7622100 compares:
| Model | Control Circuit | Manual Control | Key Difference |
|---|---|---|---|
| 7620 | Tinned Wire | Yes | Basic model with tinned wire connection |
| 7620100 | Deutsch DTM / Amphenol ATM | Yes | Deutsch/Amphenol connector option |
| 7621 | Tinned Wire | No | No manual control |
| 7621100 | Deutsch DTM / Amphenol ATM | No | Deutsch/Amphenol, no manual control |
| 7622 | Tinned Wire | Yes | Tinned wire, includes Contura Switch |
| 7622100 | Deutsch DTM | Yes | Deutsch connector, includes Contura Switch |
| 7623 | Tinned Wire | Yes | Higher voltage option (24V) |
| 7623100 | Deutsch DTM / Amphenol ATM | Yes | 24V with Deutsch/Amphenol connector |
The 7622100 is ideal for users seeking a 12V relay with a secure Deutsch DTM connector and manual control, offering a balance of advanced features and reliability.
Pricing and Availability
- MSRP: $332.84
- Retail Price: Approximately $281.99 (varies by retailer)
- Where to Buy: Available at marine retailers like West Marine, Hodges Marine, and online platforms. Check Blue Sea Systems’ website for authorized dealers or to Find a TECH Installer.
- Payment Options: Some retailers offer financing, such as Affirm for orders over $50.
- Warranty: Blue Sea Systems provides a lifetime warranty, ensuring peace of mind for long-term use.
Integration with Remote Battery Management Systems
The ML-ACR pairs seamlessly with Blue Sea’s ML-RBS (Remote Battery Switch) to create a comprehensive battery management subsystem. This combination allows users to:
- Share alternator charge between start and auxiliary batteries automatically.
- Combine batteries momentarily for emergency starting via a remote switch.
- Connect multiple remote battery switches using the optional ML Series Link Bus (PN 9160) for centralized control.
This subsystem is particularly valuable for larger vessels with complex electrical demands, offering push-button control and enhanced monitoring.
Safety and Compliance
The Blue Sea 7622100 ML-ACR meets stringent marine standards, including:
- CE Marked: Certified for European safety and environmental requirements.
- IP66: Resistant to powerful water jets and dust, ensuring reliability in marine conditions.
- ISO 8846: Compliant with marine ignition protection standards.
- SAE J1428: Meets standards for electrical components in marine environments.
The relay also includes a California Proposition 65 warning for chemicals like di(2-ethylhexyl)phthalate (DEHP), which may pose health risks. Always handle and install with care, following safety guidelines.
Why Choose the Blue Sea 7622100 ML-ACR?
The Blue Sea 7622100 ML-ACR stands out for its:
- Versatility: Suitable for recreational boats, fishing vessels, and liveaboards.
- Reliability: Robust construction and lifetime warranty ensure long-term performance.
- User-Friendly Design: Manual control, clear indicators, and easy installation cater to both novices and professionals.
- Energy Efficiency: Magnetic latching technology minimizes power consumption.
- Safety Features: Start and engine isolation protect electronics, while the LOCK OFF function enhances servicing safety.
Whether you’re upgrading an existing system or outfitting a new vessel, the ML-ACR delivers unmatched performance and peace of mind.
Final Verdict: Is It Worth It?
Pros:
- 500A continuous rating (best-in-class).
- Ultra-low power consumption.
- Manual control for emergencies.
- Dual-sensing for accurate charging.
Cons:
- Higher price than basic solenoids.
- Remote LED requires additional wiring.
Who Should Buy It?
- Boat owners with dual battery banks.
- RV users needing reliable off-grid charging.
- Anyone running high-power alternators (300A+).
Alternatives
- Blue Sea SI-ACR (Lower cost, but no manual control).
- Victron Cyrix Li (Lithium-focused, but lower amp rating).
Conclusion
The Blue Sea 7622100 ML-ACR Automatic Charging Relay with Manual Control is a game-changer for marine electrical systems. Its ability to manage dual battery banks with precision, combined with features like manual override, dual sensing, and robust construction, makes it a top choice for boaters worldwide. With a 4.7 out of 5 customer rating, real-world users confirm its reliability, ease of use, and durability in demanding conditions.
Priced at approximately $281.99 (MSRP $332.84), it’s an investment in safety and efficiency, backed by a lifetime warranty. Whether you’re navigating coastal waters or embarking on extended voyages, the ML-ACR ensures your batteries are charged, your electronics are protected, and your boat is ready for any challenge. Upgrade your marine electrical system with the Blue Sea 7622100 ML-ACR and experience the confidence of uninterrupted power on the water.
For more details or to explore API services for advanced integrations, visit https://x.ai/api. To purchase or find an installer, check Blue Sea Systems’ official website or trusted marine retailers.
Happy Boating!
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