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Morningstar SunSaver Duo SSD-25RM > 25 Amp 12 Volt PWM Charge Controller Includes Remote Meter & 33' Cable

Morningstar SunSaver Duo SSD-25RM > 25 Amp 12 Volt PWM Charge Controller Includes Remote Meter & 33' Cable

Our Price: $167.00
Warranty: 5 Years


Description Datasheet

Morningstar SunSaver Duo > 25 Amp 12 Volt PWM Charge Controller > Includes Remote Meter & 33' Cable

Manufacturer Part Number: SSD-25RM

Morningstar's SunSaver Duo (SSD-25RM) 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 employs Morningstar's legendary SunSaver controller technology, whose long-term track record for high reliability and improved battery charging is well-recognized in the solar industry. This controller also includes a backlit remote meter which may be mounted in or on a wall, and displays digital and pictorial status information about the solar power system.

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.


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. Five year warranty and estimated 15 year life.


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
Remote Meter Not Included Included


  • Operating Ambient Temperature Controller 40C to +45C / 40F to +113F

    Meter 20C to +60C / 4F to +140F
  • 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
LEDs Charging status
Battery level
Displays Battery #1 & #2 voltage
Battery charge priority
Minimum / maximum voltages
Solar charging amps / amp-hours

Electronic Protections

  • Solar Short Circuit
  • High Temperature
  • Solar Over Current
  • Lightning
  • Reverse Polarity
  • Reverse Current at Night

Battery Charging

The SunSaver Duo charges both sealed and flooded lead-acid batteries per the charging specifications in table 1 below. Sealed batteries are typically maintenance-free batteries that do not require water. Flooded batteries have removable caps that allow the addition of water when needed. DIP switches 1 & 2 select the battery type for Battery #1 and Battery #2 respectively. Choose the correct battery type for each battery.

DIP Switch OFF: Sealed battery type (factory pre-set)
DIP Switch ON: Flooded battery type
  • Regulation Voltage Sealed Battery 14.1 volts (at 25C, 77F)

    Flooded Battery 14.4 volts (at 25C, 77F)
  • Float Voltage 13.7 volts
  • Equalization Voltage* 14.8 volts
  • Temp. Compensation 30 millivolts per C (25C 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


  • 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


  • Remote Temperature Sensor Measures temperature at battery for improved battery charging


  • CE Compliant
  • Manufactured in a certified ISO 9001 facility

Warranty: Five year warranty period. Contact Morningstar for complete terms.

Detailed Description

Features Diagram

The major features of the SunSaver Duo are shown below. An explanation of each feature is provided.

SunSaver Duo

  • Remote Temperature Sensor (RTS) Terminals

    A connection point for a Morningstar RTS (optional) to remotely monitor battery temperature.

  • Local Temperature Sensor

    Measures ambient temperature. Battery regulation is adjusted accordingly.

  • Status LED Indicator

    Provides system status and error indication.

  • Settings DIP Switches

    Adjustment switches that define the operating parameters of the SunSaver Duo.

  • Battery #1 Power Terminals

    Power connections for battery #1.

  • Solar Input Power Terminals

    Power connections for solar module(s).

  • Battery #2 Power Terminals

    Power wire connections for battery #2.

  • Remote Meter Connection (RJ-11)

    A communication port for the Morningstar Remote Meter.

Frequently Asked Questions
  • How do I size my charge controller?

    Take the total wattage of your array (number of panels x watts per panel) and divide it by the voltage of your battery bank to get amps, then round up. The amp rating of your charge controller must exceed this number. If you need any assistance sizing your charge controller, please don't hesitate to call us at 888-899-3509 ext 1.

  • Should I get an MPPT or PWM charge controller?

    Simply put, if the voltage of your panels is close to the voltage of your battery bank, a PWM charge controller is an affordable choice. However, if your panel voltage is much higher than your battery bank, you should use an MPPT controller because it is designed to convert that higher voltage into amps, which will charge your batteries faster and provide you with a more efficient system.

Average Customer Review: Average Customer Review: 5 of 5 5 of 5 Total Reviews: 3 Write a review.

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  0 of 0 people found the following review helpful
5 of 5 sunsaver duo 25 rm with rts June 18, 2014
Reviewer: Charles Kincaid from Tijeras, NM United States  
Morningstar's Sunsaver Duo 25 is the sweetspot for price and features of the high quality controllers. For RV small system in a boondocker's cabover camper, it is perfect solution for 220 AH storage and nominal 300W panel output from DMsolar. Fired for first time this AM in the brilliant NM sun, it worked flawlessly. Remember to use really big wire, #10 on top, #6 from combiner box to controller, #3/0 for controller to Batt and from Batt to DC load center. V drops all way under 1%. No more chargers or generators!

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  1 of 1 people found the following review helpful
5 of 5 sun saver duo controller June 5, 2011
Reviewer: John from Longmont, CO United States  
the controller installed very easy.  I will be camping in a few days where there are no hookups so this will be the first test.

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  0 of 0 people found the following review helpful
5 of 5 Charge Controller May 22, 2011
Reviewer: Ronald Fitzpatrick from Center Barnstead, NH United States  
Nice that the duo comes with a meter.

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