Victron Energy Buck-Boost DC-DC Converter, 12/24V Service Battery Charging

Overview

The Victron Energy Buck-Boost DC-DC Converter is a programmable DC-DC charger for charging a 12V or 24V service battery from a 12V or 24V starter battery and alternator system. It works across a 10-30V input range and a 10-30V output range, making it useful on boats with mixed-voltage DC systems or alternator-fed house battery charging layouts.

This converter regulates charge voltage where alternator output can move too high or too low for the service battery. A built-in engine running detection system helps prevent deep discharge of the starting battery, and the unit can also be activated through a programmable input such as D+, CAN bus on supported models, or a (+)15 connection.

For marine installations, it is a practical fit where a house or auxiliary battery bank needs controlled charging while the engine is running. It is not a shore-power charger or solar controller; it belongs in the DC charging side of the system, between the engine battery and the service battery bank, with model selection based on the required charge current.

Key features

• Supports 12V, 24V, and 12/24V system layouts, with charging from either a 12V or 24V alternator and starter battery to a 12V or 24V auxiliary battery.
• 10-30V input and output voltage ranges suit common low-voltage DC charging systems found on marine and mobile installations.
• Programmable charge voltage helps protect the service battery from alternator output that may be too high or too low.
• Built-in engine running detection helps avoid draining the starting battery when the engine is not providing charge.
• Charge current and input current limiting help match the converter to the alternator, wiring, and battery bank requirements.
• Input and output LED status indicators give quick visual feedback during installation, testing, and fault checks.
• Operating temperature range of -25°C to +60°C supports use in technical spaces where temperature can vary through the season.

Variants

The Buck-Boost DC-DC Converter is offered in three charge-current configurations. Each version supports the same 10-30V input and output voltage range, with the main difference being the maximum charge current available for 12V and 24V charging.

The 25A model is the lower-current option and does not have a CAN bus connection. The 50A and 100A models add higher charge-current capacity for larger service battery banks and installations where the alternator and wiring are sized accordingly.

• ORI303025000: Maximum charge current is 25A at 12V and 15A at 24V. This version suits smaller auxiliary or service battery charging setups where a lower current limit is appropriate.
• ORI303050000: Maximum charge current is 50A at 12V and 25A at 24V. This version provides a middle current level for installations that need faster service battery charging without moving to the largest unit.
• ORI303100000: Maximum charge current is 100A at 12V and 50A at 24V. This version is the high-current option for larger battery banks and charging systems sized for heavier alternator-to-service-battery transfer.

Installation and setup

The converter should be installed as part of the vessel’s DC charging system with cable size, fusing, ventilation, and mounting location matched to the selected current rating. The higher-current models place more demand on cabling and alternator capacity, so the current variant should be selected together with the battery bank size and the charging limits of the engine system.

Programming is handled through a PC application using a USB connection. During commissioning, the charge settings, current limits, and activation behavior should be checked before regular use, especially on boats with lithium service batteries or alternator protection requirements.

Compatibility and use on board

This converter is a good match for vessels that need controlled charging of a house or auxiliary battery bank from an engine-driven DC source. It can be used in 12V and 24V battery layouts, including mixed 12/24V systems where the starter side and service side are not the same voltage.

It is especially useful for owners upgrading DC charging control, adding a dedicated service bank, or managing alternator charging where simple direct battery-to-battery wiring is not appropriate. Final compatibility depends on the vessel’s alternator output, battery chemistry, wiring, protection devices, and the selected charge-current variant.