Votronic MPPT 25A Duo (Dual) 350 Marine Version Solar Charge Controller

Votronic MPPT 25A Duo 350 Marine Solar Charge Controller: Precision Dual-Battery Charging for Harsh Environments

Advanced MPPT Technology for Maximum Solar Yield in Marine and Mobile Applications

The Votronic MPPT 25A Duo 350 Marine Version is a high-performance solar charge controller engineered for demanding off-grid energy systems in motorhomes, caravans, and marine vessels. Utilising Maximum Power Point Tracking (MPPT) technology, this controller continuously optimises the power output from your solar array, delivering up to 30% more charging current compared to conventional PWM controllers. This efficiency gain is particularly noticeable during overcast conditions, low-light winter months, or when solar irradiance is variable, ensuring your batteries receive a reliable charge when you need it most.

Designed specifically for 12V battery systems, the Votronic MPP 350 Duo supports solar arrays up to 350Wp with a maximum input voltage of 50V (Voc) and current up to 21A. Its high-frequency switching design achieves an efficiency exceeding 95%, minimising energy losses and maximising the usable power delivered to your battery bank.

Humidity-Proof Construction for Marine and Coastal Reliability

This Marine Version features a humidity-proof design, making it suitable for installation in environments where moisture and condensation are a concern, such as boats, coastal caravans, and motorhomes. The conformally coated electronics protect against corrosion and electrical faults caused by damp air, significantly reducing the risk of premature failure compared to standard controllers. Both the controller and any connected display must be installed inside the vehicle or vessel, away from direct water exposure, to maintain this protection.

Simultaneous Dual-Battery Charging with Intelligent Prioritisation

One of the standout features of the Votronic MPP Duo series is its ability to charge two independent battery banks simultaneously. The primary output delivers up to 25.5A to your house/service battery (BOARD I), while a secondary output provides up to 1A of support and trickle charging to your vehicle's starter battery (Start II). This ensures your engine battery remains topped up during storage or extended off-grid stays, preventing the inconvenience of a flat starter battery. Both outputs are protected against overcharging, reverse current, and overload.

Adaptive Charging Profiles for Lead-Acid and LiFePO4 Batteries

The controller features a sophisticated IU1oU2 charging characteristic with selectable profiles for various battery chemistries. It includes 3 pre-configured programs for lead-acid, gel, and AGM batteries, plus 5 dedicated programs for LiFePO4 (Lithium Iron Phosphate) batteries with integrated Battery Management Systems (BMS). The LiFePO4 profiles incorporate temperature-based protection, automatically adjusting charging parameters to safeguard the battery against extreme temperatures. For lead-acid batteries, an optional temperature sensor (Order No. 2001) enables voltage compensation, improving charge acceptance in cold weather and reducing gassing in high temperatures.

Key Features at a Glance

• MPPT technology boosts charging current by 10% to 30% versus standard controllers, especially in low-light conditions
• Dual-battery charging with 25.5A main output and 1A trickle charge for starter battery maintenance
• Humidity-proof electronics for reliable operation in marine and high-moisture environments
• Wide solar input range up to 350Wp, 50V Voc, and 21A for flexible panel configurations
• 8 selectable charging programs for lead-acid, gel, AGM, and LiFePO4 batteries with temperature protection
• AES refrigerator output automatically switches compatible Dometic/Electrolux fridges to 12V when excess solar power is available
• Integrated 30A blade fuse and comprehensive protection against overload, overheating, short circuit, and reverse polarity
• Plug-in ready for Votronic LCD Solar Computer S, VPC, or Bluetooth Connector for system monitoring
• EBL measurement output for compatibility with Schaudt Elektroblock displays (cable set Art. 2007 required)
• Automatic charging cable compensation corrects voltage drop for accurate battery charging

Smart Energy Management with AES Refrigerator Control

The built-in AES (Automatic Energy Selector) terminal intelligently switches compatible Dometic or Electrolux absorption refrigerators from gas to 12V operation when surplus solar energy is available. This maximises the use of free solar power, reducing gas consumption and extending your off-grid autonomy. An LED indicator clearly shows when the AES function is active.

Comprehensive System Monitoring and Integration

Stay informed about your solar system's performance with the controller's intuitive LED indicators, which display MPP operation, battery state of charge (>80%, Full), AES status, and low voltage warnings. For more detailed data, the controller is plug-in ready for the Votronic LCD Solar Computer S, VPC, or Bluetooth Connector, allowing you to monitor charging currents, battery voltage, and energy yields in real time. Additionally, the EBL measurement output enables integration with Schaudt Elektroblock systems, displaying solar current on your existing control panel (compatibility should be verified prior to installation).

Built to Last with Robust Protection Features

Safety and longevity are paramount in mobile installations. The Votronic MPP 350 Duo includes an integrated 30A blade fuse for circuit protection, along with electronic safeguards against overload, overheating, short circuit, and reverse battery connection. The on-board mains suppression filter ensures trouble-free parallel operation with other charging sources such as alternators, mains chargers, or generators. With an operating temperature range of -20°C to +45°C and CE/E-approval for vehicle use, this controller is built to perform reliably in Australian conditions.

Compact and Lightweight Design for Easy Installation

Measuring just 77 x 131 x 40 mm and weighing only 285 g, the Votronic MPP 350 Duo is easy to install in tight spaces typical of motorhome and marine electrical compartments. The clearly labelled terminals accept solar panel and battery connections with ease, and the included wiring diagram simplifies setup for both professional installers and experienced DIY users.

Upgrade Your Off-Grid Power System Today

Whether you're cruising the coast, exploring the outback, or living off-grid, the Votronic MPPT 25A Duo 350 Marine Solar Charge Controller delivers the efficiency, durability, and intelligent battery management you need. Order now to maximise your solar harvest and protect your batteries with advanced MPPT technology designed for the toughest environments.