Victron Quattro Dual AC Input Setup: Generator Priority, PowerControl, and PowerAssist

Key Takeaways

• The Victron Quattro inverter/charger is designed to manage two distinct AC inputs, typically prioritising a generator on AC-in 1 over the grid on AC-in 2.
• PowerControl limits the current drawn from an AC input source, preventing overload, while PowerAssist supplements input power with battery energy during high demand.
• Configuration of these features, including automatic generator start/stop, is performed using VEConfigure software and Assistants.
• Installation, firmware updates, and any settings related to grid interaction must be carried out by a qualified electrical engineer or Victron-trained professional.

Setting Up Dual AC Inputs on Your Victron Quattro

The Victron Quattro inverter/charger is engineered to handle two separate AC input sources, offering flexibility for systems that use both a generator and the utility grid. This capability allows for sophisticated power management, ensuring continuous supply and optimising energy use. For typical backup systems, the generator is wired to AC-in 1, and the mains (grid) supply is connected to AC-in 2. The Quattro can then be configured to automatically manage the switching between these sources.

How the Quattro Manages Power: Switching, PowerControl, and PowerAssist

The Quattro's core function is to provide uninterrupted power by intelligently switching between available AC sources and, when necessary, supplementing them with battery power.

When both AC inputs are available, the Quattro can be programmed to prioritise one over the other. For instance, it can be set to stop the generator and switch to grid power when the grid becomes available. This is managed through its internal transfer switch and configurable settings.

PowerControl is a feature that limits the amount of AC current drawn from an input source. This is crucial when connected to a generator or a limited shore power supply, preventing these sources from being overloaded. When the total load (including battery charging) approaches the set limit, the Quattro will first reduce the current it uses for battery charging to stay within the boundary.

PowerAssist works in conjunction with PowerControl. If the AC input current limit is reached and reducing the charge current is insufficient to meet the system's demands, PowerAssist will automatically draw power from the battery, convert it to AC, and add it to the incoming AC supply. This allows the system to handle peak loads that exceed the capacity of the AC input source alone, preventing tripping of breakers or generator overload.

Configuring Dual AC Inputs and Power Management

Configuration of the Victron Quattro's dual AC input and power management features is primarily done using the VEConfigure software. This software allows access to various settings, including input current limits, generator management, and the use of Assistants for complex logic.

Managing Generator Power with the Quattro

Integrating a generator into a Victron Quattro system requires careful configuration to ensure reliable operation. The Quattro's ability to manage two AC inputs makes it ideal for generator-grid setups.

To set up automatic generator start/stop, you use the Virtual Switch option in VEConfigure. This allows you to define conditions, such as battery voltage or State of Charge (SOC), that will trigger the generator to start or stop. The generator's control input is wired to the Alarm relay on the MultiPlus/Quattro, using the Normally Closed (NC), Normally Open (NO), and Common (COM) terminals.

Generators, especially smaller or older models, can produce unstable AC power. The Quattro offers specific settings to improve its compatibility with such sources:

• Disable UPS mode: This can help if the generator struggles with the Quattro's fast transfer times.
• Enable Dynamic Current limiting: This feature helps the Quattro adapt to fluctuations in generator output.
• Weak AC: Turning on this setting can assist the Quattro in synchronising with generators that have distorted sine waves.
• Adjusting Voltage and Frequency windows: These settings define the acceptable range for AC input voltage and frequency. Widening these windows can allow the Quattro to accept a broader range of generator outputs, but care must be taken not to exceed safe operating limits for connected loads.

If the generator still struggles, common issues include the generator's power being outside the inverter/charger's programmed settings, or the generator stalling due to overload, especially with AVR (Automatic Voltage Regulation) equipped units. Inverter-based generators may electronically overload without visibly stalling, leading to the system not charging. Poor sine wave quality, particularly during sudden load changes, can also cause frequent disconnections.

What you can change yourself, and what you cannot

As a system owner, you can typically adjust operational settings that do not impact grid interaction or system safety. This includes configuring the Virtual Switch for generator start/stop conditions (e.g., battery SOC thresholds), setting PowerControl limits within the safe operating range of your generator or shore power, and adjusting load management for the AC-out-2 auxiliary output.

However, certain configurations and procedures must be handled by a qualified electrical engineer or a Victron-trained installer. This includes:

• Initial Installation: "This product may only be installed by a qualified electrical engineer." This ensures correct wiring, grounding, and compliance with local electrical standards (e.g., NRS 097-2-1 in South Africa). Every system installation must include a way to disconnect the AC and DC circuits.
• Firmware Updates: "This operation must only be carried out by Victron-trained Engineers, Installers and Dealers, and must not be attempted by system Owners and Users." Incorrect firmware updates can lead to critical system issues and loss of settings.
• Grid-related Settings: Any settings that affect the inverter's interaction with the utility grid, such as Loss of Mains (LOM) detection parameters or export limits, require professional configuration to ensure compliance with grid codes and safety regulations. Disabling LOM on a grid-connected input is only allowed if external anti-islanding safety equipment is installed.
• Troubleshooting VE.Bus Errors: Complex communication errors (e.g., "Error 3 - Not all, or more than, the expected devices were found in the system") or issues related to mixed VE.Bus protocol types (e.g., "Error 2 - New and old type MK2 protocol mixed in the system") typically require expert diagnosis.
• Opening the Unit: Opening the inverter/charger enclosure should only be done by authorised service personnel after isolating all AC and DC power and waiting for capacitor discharge.

Working on live AC tails or battery connections without proper training and safety equipment is extremely hazardous and can invalidate your Certificate of Compliance (CoC).

What the published sources do not tell you

While the Victron documentation provides extensive detail on the Quattro's features, some specific information relevant to a South African context or detailed setup scenarios is not explicitly covered:

• Specific Quattro Models and Ratings: The documentation refers generally to "Quattro-II 230V" and "Quattros" but does not provide a detailed table of specific models (e.g., 3kVA, 5kVA, 10kVA) with their individual continuous power, charge current, or AC input current limits. This information would typically be found in individual product datasheets.
• Detailed AC Output Configuration (AC-out-1 uninterrupted, AC-out-2 auxiliary load): While the Quattro is known for its dual AC outputs, the provided sources do not offer detailed configuration steps or specific use cases for AC-out-1 (uninterrupted) and AC-out-2 (auxiliary load) beyond general mentions.
• South Africa Specific Information: There is no information regarding grid codes, regulations (like NRS 097-2-1), or common practices specific to South Africa within the provided Victron documentation excerpts. Users must consult local regulations and qualified installers for compliance.
• Specific Wiring Diagrams for Dual AC Input: While the concept of AC-in-1 (generator) and AC-in-2 (grid) is mentioned, detailed wiring diagrams showing the physical connections for this specific setup are not included.
• Comprehensive PowerControl/PowerAssist Configuration Steps: While the existence and function of PowerControl and PowerAssist are described, a step-by-step guide for configuring these features in VEConfigure for a dual AC input scenario is not fully detailed.
• Advanced Assistant Combinations: The documents mention combining multiple assistants and their execution order but do not provide specific examples or best practices for complex combinations relevant to dual AC input management beyond the "Ignore AC input" example.
• VE.Bus Error 11: Details for "Error 11" are mentioned in some Victron FAQs but are not included in the provided error code list.