Aux Load Settings

Summary / Purpose

This article explains how to configure the Aux Load, Generator Input, and Micro-Inverter (AC-Coupled) Input settings on Sunsynk inverters.
These settings determine how the inverter interacts with solar, battery, generator, and AC-coupled systems.

Supporting documentation:

• Gen Input wiring and logic: https://sunsynk.freshdesk.com/a/solutions/articles/103000272545

• AC-coupled wiring and logic: https://sunsynk.freshdesk.com/a/solutions/articles/103000303461

1. Generator Input Settings

Use these when connecting a generator to the inverter for automated start/stop control and peak-shaving.

1.1 Gen Peak-Shaving (GPS)

Gen Peak-Shaving allows the inverter to discharge the batteries to ensure generator usage does not exceed a set power limit.
It prevents periods of high generator consumption while minimizing battery usage.

Key behaviours:

• Enabling GPS automatically enables Time of Use (TOU).

• GPS and TOU interact using Power (W) and Battery (Batt) values in the TOU table.

Refer to:
https://sunsynk.freshdesk.com/a/solutions/articles/103000272545

1.2 Gen Peak-Shaving Power

The power threshold where the inverter begins discharging the battery to reduce generator load.

1.3 Battery Start/Stop SOC

• OFF% — When battery SOC reaches this value, the inverter stops the generator signal, turning it off.

• ON% — When battery SOC drops below this value, the inverter sends a start signal (via GS pin) to turn the generator on.

1.4 GEN Connected to Grid Input

Enable this setting when the generator is wired to the Grid Input of the inverter.

2. Aux Load Output Settings

These settings control when the inverter diverts power to the Aux Load / Gen Port.

2.1 Solar Power Threshold

When solar production reaches or exceeds this value, the inverter diverts power to the Aux port.

2.2 Battery SOC Control

• Aux Load OFF Batt % — SOC at which the inverter stops diverting power to the Aux port.

• Aux Load ON Batt % — SOC at which the inverter starts diverting power to the Aux port.

2.3 Behaviour Options

• On Grid Always On — Grid keeps the Aux port powered continuously.

• Off Grid Immediately Off — When grid fails, the inverter immediately stops diverting power to the Aux port.

3. Micro-Inverter Input (AC-Coupled) Settings

Used when integrating string inverters or micro-inverters feeding AC power into the system.

Refer to:
https://sunsynk.freshdesk.com/a/solutions/articles/103000303461

3.1 AC Couple OFF Batt %

When battery SOC reaches this value, the inverter stops using incoming power from the AC-coupled inverter.

3.2 AC Couple ON Batt %

When battery SOC is below this value, the inverter resumes using AC-coupled power.

3.3 AC Couple Frz High

This is the frequency used by the inverter to detect active string/micro-inverters on the property.

Troubleshooting / Notes

• GPS (Gen Peak-Shaving) always activates TOU automatically. Adjust both tables together to avoid unexpected generator behaviour.

• Aux Load and AC-coupled logic both rely heavily on SOC thresholds — ensure they are set logically to avoid rapid cycling.

• If using images or wiring diagrams, reference the official documentation links above.