Morningstar’s SunSaver Duo is an advanced PWM two battery controller for RV’s, caravans, boats and cottages.

This product will charge two separate and isolated batteries at the same time, such as a “house” and an engine battery, based on user selectable priorities.


The SunSaver Duo is epoxy encapsulated for environmental protection, is user adjustable via DIP switch or connection to a personal computer, and has an optional remote temperature sensor.

Key Features and Benefits:   Two Battery Charging Solar charge current is shared between the two batteries based on a user selectable priority.

When one battery is fully charged, all of the charge current flows to the other battery.  

Provides Useful information

The remote meter and LED’s display system status data and any system errors.

Custom icons and back lighting make the meter easy to read and understand. 

Lower Cost Two battery charging eliminates the added cost of two separate solar charging systems and the need for isolation between the batteries.   easy to install The controller is installed near the batteries using the clearly   labeled large wire terminals.

The remote meter may be mounted in the wall or on the wall using the included frame. Also includes the meter wiring with RJ-11 connector. 

longer Battery life Four stage series PWM pulse charging and temperature compensation increases the useful life of the batteries.   extensive electronic Protections The controller will not be damaged by wiring mistakes during installation. There are no fuses to replace, and the controller will automatically re-set after a wiring mistake.  highly reliable Epoxy encapsulation protects the controller against dust and high humidity. Efficient electronics and a conservative thermal design allow the controller to operate reliably  at high temperatures.

25 amps at 12 volts DC

Manufacture warranty: Five year warranty period.

Technical Specifications


electrical • Rated Solar Input 25 amps • Rated Load Output Not applicable • Battery Voltage 12 volts • Min. Battery Voltage  1 volt • Max. Battery Voltage 15 volts • Max. Solar Voltage 30 volts • Self Consumption Controller 6 to 10 milliamps Remote meter 6 to 15 milliamps environmental • Operating Ambient Temperature Controller –40°C to +45°C / –40°F to +113°F Meter –20°C to +60°C / –4°F to +140°F • Humidity 100% non-condensing •  Tropicalization   Controller Epoxy encapsulation   Anodized aluminum case   Corrosion resistant terminals  Meter Conformal coated printed circuit board meter Displays • Backlighting Push button activated • LED’s Charging status  Errors  Battery level • Displays Battery #1 & #2 voltage  Battery charge priority  Minimum / maximum voltages  Solar charging amps / amp-hours   Temperature   Errors electronic Protections • Solar Short Circuit • High Temperature • Solar Over Current • Lightning • Reverse Polarity • Reverse Current at Night
Battery Charging • Regulation Voltage Sealed Battery 14.1 volts (at 25°C, 77°F)  Flooded Battery 14.4 volts (at 25°C, 77°F) • Float Voltage 13.7 volts • Equalization Voltage*  14.8 volts • Temp. Compensation  –30 millivolts per °C (25°C reference) • Type of Charging  Series PWM 4 stage: bulk, PWM, float,   and equalize*   *used on flooded battery only •  Battery Charging   Priority 90% / 10%   50% / 50%   Customize via PC connection mechanical • Controller 17.0 x 5.6 x 4.1 cm / 6.7 x 2.2 x 1.6 in. • Meter 9.7 x 9.7 x 3.1 cm / 3.8 x 3.8 x 1.2 in. • Meter back 7.4 cm / 2.9 in. diameter   2.8 cm / 1.1 in. deep   Fits 7.6 cm / 3 in. round hole • Weight  Controller 260 g / 0.57 lb Meter 135 g / 0.30 lb • Largest wire 16 mm2   (#6 AWG) • Meter wire 10 m / 33 ft options •  Remote Temperature Sensor — Measures temperature  at battery for improved battery charging Certifications • CE Compliant • Manufactured in a certified ISO 9001 facility

 In Wall Mount  Frame Mount Back 
Battery 2Battery 1
Solar Module