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Photonic Universe

Morningstar SunSaver Duo 25A 12V dual battery solar controller for caravans, motorhomes, boats and yachts

Morningstar SunSaver Duo 25A 12V dual battery solar controller for caravans, motorhomes, boats and yachts

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25A dual battery solar charge controller / regulator for independent charging of two 12V batteries (can be used with 1 battery too) for solar panels up to 400W

SPECIAL NOTICE : If you are purchasing this part for a self build project, please see our terms & conditions. FULFILLED BY PHOTONIC UNIVERSE : This product is fulfilled by Photonic Universe, our Solar partner.



As an official distribution partner of Morningstar products across the globe, we are proud to offer solar charge controllers from this world-leading supplier. Innovative design from years of dedicated research and superior build quality enable these top-of-the-range solar charge controllers to extend battery capacity and life, maximise energy production, and consistently achieve high performance standards.

This high quality Morningstar SunSaver Duo 25A 12V dual battery solar charge controller is well-recognised as the most powerful dual battery controller on the market and is suitable for various applications.

It is perfect for caravans, motorhomes, boats or other systems with 2 batteries (e.g. engine and leisure battery). You can set initial charging priority e.g. 90% engine battery and 10% leisure battery. When one of the batteries is fully charged the controller will automatically divert all power to the other battery.

Other key features of this controller include:

  • Extremely high reliability, with a long 5 year warranty and estimated 15 year life
  • Negative common ground - ideal for most motorhomes, boats and stationary applications
  • Epoxy encapsulation protects the controller against dust and high humidity
  • Four stage series PWM pulse charging increases your battery life
  • Specific settings, such as slow switching charging mode for sensitive loads to avoid interference
  • Lower system cost as the two battery charging eliminates the need for two separate solar power systems
  • Easy to install and use, with factory pre-sets, fully automatic operation and fault recovery


Can the unit work with only 1 battery? Yes, absolutely! The controller will determine automatically if there's only 1 battery connected and will pass 100% of charging current to this battery. You can add a second battery later.

This powerful 25A controller can work with solar panels up to 400W. It has many protection functions, such as stopping reverse current at night (from the battery to the solar panel), over charge, short circuit, reverse polarity etc. Other features include an LED status indicator, battery type selection (sealed, or flooded - two batteries can have different types) and RJ-11 socket for a remote LCD meter (see Morningstar SunSaver Duo 25A dual controller with LCD remote meter). A built-in temperature sensor allows charging adjustment depending on the ambient temperature.

Click on the Details and Specifications tab for more information about this product.

Details & Specification


Controller specifications:

  • Rated charging current: 25A
  • Fully automated operation for 12V system
  • Maximum solar input power: 400W or 25A
  • Minimum battery voltage: 1V
  • 3 pairs of terminals (battery 1, solar, battery 2)
  • LED indicator to show operational state and system errors
  • Temperature sensor for temperature compensation of charging (-30mV/C/12V)
  • RJ-11 connection point for a remote meter (not included)
  • Various protection features (over charge, short circuit, reverse polarity etc)
  • Self-consumption: 5.5mA at night, 10mA when charging
  • Grounding: negative common ground
  • Working temperature: -40C to +45C
  • Terminals for wire up to 16mm2
  • Size: 168.8 x 55.1 x 34.5 mm
  • Weight: 260 g
  • Multiple mounting holes for ease of installation


The product is covered by 5 year warranty. For more information please refer to our Terms and Conditions.




The product comes with an instruction manual (see the 'Documents' tab for a download link) which explains connections and operations.

If you need help with installation or have any technical questions we can provide FREE support - please contact us by email or phone (see Contact Us page for more information).


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