Mastervolt MASS 24/25-2 Battery Charger - 230 V 50/60 Hz

The Mastervolt MASS 24/25-2 battery charger is designed to provide a stable and efficient power supply for demanding marine applications, both professional, semi-professional, and recreational. It charges connected batteries and maintains their charge level.

This charger operates with a nominal input voltage of 230 V (range 180–265 V) and provides an output voltage of 24 V DC. It delivers a total charging current of 25 A.

The charger is compatible with a wide range of battery types, including Gel, AGM, lead-acid, and Lithium Ion batteries. It uses an automatic 3-stage+ IUoUo charging characteristic tailored to these battery chemistries.

The Mastervolt MASS 24/25-2 charger is equipped with two battery outputs:

One main output delivering up to 25 A. A secondary 3 A output, intended for maintaining a small battery, such as a starter battery.

It is suitable for battery banks with a capacity between 50 and 250 Ah. This capacity can be extended depending on your installation requirements.

Yes, the charger is equipped with DC voltage compensation to ensure precise and optimal battery charging. A battery temperature sensor with cable and connector is also included to adjust the charging voltage based on temperature.

The maximum input power of the Mastervolt MASS 24/25-2 charger is 800 W.

The charger must be installed in a well-ventilated space protected from rain, snow, spray, steam, bilge moisture, and dust. Recommended ambient conditions are a temperature of 0 to 60°C and humidity of 0 to 95% without condensation.

The charger can operate within an ambient temperature range of 0 to 60°C (32°F to 140°F). However, power output is reduced above 40°C (104°F) to maintain the heat sink's internal temperature.

For installation, the following tools are recommended as a minimum:

A 13 mm socket wrench to secure the DC cables (battery). A Phillips screwdriver to open the charger’s connection area. A 2 mm flathead screwdriver for the sensing terminal.

If you are using a battery isolator (which can cause a 0.6 V voltage drop), you can compensate for this loss by setting DIP switch 4 to the 'On' position (Diode enabled). This function adds a +0.6 V compensation to the charging voltage.

Yes, the charger is equipped with a dry-contact alarm relay. The alarm function has two modes: a standard mode (factory setting) and a DC alarm mode (continuous mode).

The charger housing can be mounted on a surface using 4 screws or bolts with a 6 mm diameter. It is important to use suitable mounting materials to support the charger’s weight, which is 3.5 kg.

Yes, the charger is compatible with MasterBus systems. Each MasterBus device is equipped with two data ports, allowing the formation of a local data network. The charger can thus communicate and be integrated into a Mastervolt energy management system.

Yes, it is possible to charge multiple battery banks simultaneously. However, if one or more battery banks need to be charged at the same time via a single output, the use of a battery isolator is recommended. This isolates the different battery banks from each other to prevent them from discharging each other.

At a temperature of 25°C, the default charging voltages are:

Bulk and Absorption: 28.5 V (for 4 hours). Float for flooded batteries: 26.5 V. Float for Gel/AGM batteries: 27.6 V.

The Mastervolt MASS 24/25-2 charger complies with the following standards and certifications: CE, ABYC A-31, RRR, and RMRS.

The charger is equipped with DIP switches that allow configuring various functions:

DIP switch 1 (Force Float): Sets the charging voltage to 26.5 V.
DIP switch 2 (Traction setting): Applies a specific setting for charging traction batteries (+0.7 V in bulk and +0.4 V in absorption).
DIP switch 3 (Gel/AGM Float): Increases the float voltage to 27.6 V for Gel/AGM batteries requiring a higher voltage.
DIP switch 4 (Diode setting): Enables diode compensation (+0.6 V) if a battery isolator is used.