What Is an Inverter Charger?
An inverter charger combines a pure sine wave inverter and a multi-stage battery charger in a single unit. In inverter mode, it converts DC battery power to 120V AC to run household appliances, tools, and electronics. In charger mode, it draws AC power from shore power or a generator to recharge the battery bank using an adaptive charging profile. An automatic transfer switch toggles between the two functions in under 20 milliseconds on Victron models, so connected loads continue without interruption when AC input fails.
Victron Energy MultiPlus Series
Buy the Victron MultiPlus inverter charger for off-grid cabins, RV builds, marine vessels, and solar backup systems requiring reliable DC-to-AC conversion with integrated battery charging. Available in 12V and 24V input configurations from 800VA to 5,000VA. PowerAssist technology prevents overload of a limited AC source, such as a small generator, by supplementing shore or generator power with battery output when loads spike. Up to six MultiPlus units connect in parallel for single-phase, split-phase, or three-phase installations. Compatible with LiFePO4, AGM, gel, and flooded batteries.
Victron Energy MultiPlus-II Series
Choose the MultiPlus-II for grid-connected ESS systems, anti-islanding compliance, and installations requiring feed-in tariff approval or external current sensing up to 32A. The MultiPlus-II adds an external current transformer option for PowerControl and PowerAssist, built-in anti-islanding, and tighter integration with Victron GX monitoring devices. Available in 12V, 24V, and 48V input configurations from 3,000VA to 5,000VA.
Victron Energy Quattro Series
Select the Quattro for systems with two AC input sources, typically grid plus generator. The Quattro accepts both inputs simultaneously and selects between them automatically, giving priority to the preferred source and switching to the secondary when needed. Available in 12V, 24V, and 48V from 3,000VA to 10,000VA. Up to six units stack in parallel for high-demand residential, commercial, and marine installations.
Sterling Power ProCombi Series
Order the Sterling Power ProCombi for straightforward marine, commercial vehicle, and RV installations where low quiescent current draw, simple installation, and reliable core performance take priority over advanced monitoring features. Available in pure sine wave (ProCombi-S) and quasi sine wave (ProCombi-Q) variants in 12V and 24V at 1,600W and 2,500W. Power factor-corrected multi-stage charging and an automatic 30A pass-through relay are standard across the range.
MultiPlus vs. MultiPlus-II vs. Quattro: Which to Choose
Each inverter/charger is designed for different power requirements and installation types. Choose the model that best fits your application.
Choose MultiPlus if you:
- Need a single AC input from shore power or a generator.
- Are building an off-grid system, RV, boat, or small cabin.
- Need up to 5,000VA of inverter output.
Choose MultiPlus-II if you:
- Want to build a grid-tied Energy Storage System (ESS).
- Need anti-islanding protection and better solar self-consumption.
- Require a single AC input with up to 5,000VA output.
Choose Quattro if you:
- Need two AC inputs, such as grid power and a generator.
- Want automatic switching between multiple power sources.
- Are powering a large off-grid, commercial, or high-demand system.
- Need up to 10,000VA of inverter output.
Choose Sterling ProCombi if you:
- Need a compact inverter/charger for marine, vehicle, or simple off-grid applications.
- Prefer low standby (quiescent) power consumption.
- Require a single AC input with up to 2,500W of output.
Key Attributes to Compare Before You Buy
- Input voltage (12V, 24V, or 48V), match to your battery bank
- Continuous output (VA/W), size to your largest simultaneous load, not average consumption
- Peak/surge capacity, required for motors, pumps, and compressors that draw 2-3x rated current on startup
- AC input sources, single input (MultiPlus) vs. dual input (Quattro)
- Transfer switch speed, under 20ms on Victron for uninterrupted load supply
- Battery chemistry compatibility, confirm LiFePO4 profile support for lithium banks
- Parallel and three-phase capability, for high-output or multi-phase installations
FAQs
What Is The Difference Between An Inverter And An Inverter Charger?
An inverter converts DC battery power to AC power for running loads. An inverter charger does this and also charges the battery bank from an external AC source, shore power or a generator, using a built-in multi-stage charger. An inverter charger replaces two separate devices and manages the transition between AC input and battery output automatically.
Can I Use An Inverter Charger Without Solar Panels?
Yes. An inverter charger operates independently of solar. It charges batteries from shore power or a generator and inverts that stored power to run AC loads when the AC source is unavailable. Solar panels connect through a separate charge controller, not through the inverter charger itself, with the exception of hybrid units like the Victron MultiPlus MPPT that integrate both functions.
What Size Inverter Charger Do I Need For An Off-Grid Cabin?
Calculate the total wattage of all loads you plan to run simultaneously, including surge draw for motors, pumps, and refrigerators, which typically start at 2 to 3 times their rated running wattage. Add 20% headroom. For a small cabin running a refrigerator, lighting, and a water pump, a 2,000W to 3,000VA unit is typically sufficient. Larger cabins with air conditioning or power tools require 5,000VA or higher.
Is Pure Sine Wave Output Necessary For An Inverter Charger?
Pure sine wave output is required for sensitive electronics, laptops, LED lighting, variable speed motors, medical equipment, and most modern appliances. Quasi sine wave (modified sine wave) inverters work for resistive loads like incandescent lighting and basic heating elements but can damage or reduce the efficiency of sensitive devices. All Victron inverter chargers and the Sterling ProCombi-S produce pure sine wave output.
Can Victron Multiplus Units Be Connected In Parallel?
Yes. Up to six Victron MultiPlus or MultiPlus-II units can be connected in parallel to increase total output current. Parallel configurations also support split-phase and three-phase installations. Each unit in a parallel system requires identical model and firmware version. Configuration is done through VEConfigure software via a VE.Bus interface.
What Is Powerassist On A Victron Inverter Charger?
PowerAssist prevents overload on a limited AC source such as a small generator or shore power connection. When connected loads exceed the capacity of the AC input, the MultiPlus supplements the shortfall by drawing additional power from the battery bank. This allows a 2,000W generator to support loads that briefly exceed its output capacity without tripping the generator or the inverter.
What Is The Difference Between The Victron Multiplus And The Quattro?
The primary difference is the number of AC inputs. The MultiPlus accepts one AC input, shore power or a generator. The Quattro accepts two AC inputs simultaneously, typically grid and generator, and automatically selects between them based on availability and priority settings. The Quattro also supports higher maximum output, up to 10,000VA, compared to 5,000VA on the MultiPlus.
Are Inverter Chargers Compatible With LiFePO4 Lithium Batteries?
Yes, provided the inverter charger has a configurable lithium charging profile. Victron MultiPlus, MultiPlus-II, and Quattro models all support LiFePO4 battery profiles and integrate with Victron Smart lithium batteries via VE.Bus for automated BMS communication. Sterling ProCombi units support lithium batteries when programmed with the correct charge voltage and current limits. Always verify compatibility with your specific battery BMS before installation.
