Victron Energy MultiPlus-II 12/3000/120-50 120V Inverter Charger

Overview

The Victron Energy MultiPlus-II 12/3000/120-50 120V is a 12V inverter/charger for boats and other mobile power systems that combines a 3000VA inverter, a 120A battery charger, and a 50A transfer switch in one unit. It supports 120VAC, 60Hz output in inverter mode and accepts single-phase 90-140VAC input for charging and pass-through from shore power or a generator.

This model is a strong fit for yachts, cruising boats, fishing boats, and onboard power refits where a 12V house bank needs to run AC loads while also charging from shore or genset power. PowerControl helps manage limited shore or generator input, while PowerAssist can add battery power during short peak-load periods.

The unit has two AC outputs. The main output keeps critical loads supplied when shore or generator power drops away, while the auxiliary output can be used for loads that should only run when AC input is available, such as a water heater. With an IP21 steel enclosure, it belongs in a dry, ventilated electrical space rather than an exposed cockpit, deck locker, or wet bilge area.

Key features

• 3000VA inverter capacity with 2400W continuous output at 25 C for common onboard AC loads.
• 120A battery charger for 12V battery banks, with adaptive charging and battery temperature sensing.
• 50A transfer switch and 50A maximum AC input current for shore power or generator integration.
• PowerControl helps prevent a limited shore power pedestal or generator from being overloaded.
• PowerAssist can supplement shore or generator power from the battery during short demand peaks.
• Two AC outputs allow critical circuits to stay powered while secondary loads disconnect during inverter-only operation.
• VE.Bus communication supports monitoring, system integration, and larger parallel, split-phase, or three-phase systems when configured correctly.
• IP21 steel enclosure with blue RAL 5012 finish for installation in a protected onboard electrical compartment.
• M8 battery terminals and 120VAC screw terminals sized for 13 mm² or 6 AWG conductors.
• Measures 578 x 277 x 148 mm and weighs 29 kg, so mounting location and service access should be planned before installation.

Variants

This product is offered in two certification configurations for the same MultiPlus-II 12/3000/120-50 120V model.

The variant difference is the certification option. The 12V DC format, 3000VA inverter rating, 120A charger rating, 50A transfer capacity, and 120V AC operating format remain the same across these two configurations.

• PMP122305110: Certification Standard. This version uses the standard certification configuration for the MultiPlus-II 12/3000/120-50 120V.
• PMP122305122: Certification UL. This version is the UL configuration for installations where that listing is part of the project or compliance requirement.

Installation and mounting

Install this inverter/charger in a dry area with good ventilation and at least 10 cm of clearance around the unit for cooling. It should be mounted on a solid surface that can support its 29 kg weight, with the battery cable run kept as short as practical to reduce voltage drop.

For marine installations, the casing must be connected to the vessel hull or grounding plate when the shore connection can be disconnected. Direct shore ground practices should be reviewed carefully because galvanic corrosion is a real concern on boats, especially in marinas with mixed shore power systems.

Electrical and system integration

The 12/3000/120-50 model uses a 9.5-17V DC input range and produces 120VAC output in inverter mode. For full output capability, the battery bank, DC fuse, cable size, AC protection, and grounding layout must be matched to the installation and checked by a qualified marine electrical professional.

VE.Bus connectivity allows the unit to work with Victron monitoring and control products such as GX devices, Digital Multi Control, VE.Bus Smart dongle, and MK3-USB for configuration. This matters on boats where the inverter/charger is part of a broader DC and AC system with solar charging, battery monitoring, generator control, or remote supervision.

Use cases on board

This model suits 12V house-bank systems that need dependable AC power for cabin outlets, galley appliances within the inverter rating, electronics, chargers, and other onboard loads while away from shore power. It is also useful for vessels that frequently move between dockside shore power, generator operation, and battery-supported anchoring.

The auxiliary AC output is especially helpful when some loads should not drain the battery bank. A water heater, for example, can be kept on an AC-input-only circuit while navigation, communications, or cabin power remain available through the main output.