Sunsynk Low Power Mode and Low Noise Mode Explained

Key Takeaways

• Sunsynk's Low Power Mode is a 'hibernation' feature that reduces inverter self-consumption and stops smart loads when battery State of Charge (SOC) is low and there is no solar generation.
• Low Power Mode activates only when the battery SOC falls below the "Low Batt" threshold and no PV generation is detected, preventing unexpected behaviour.
• Low Noise Mode changes the inverter's internal switching speed to reduce radio interference, but it does not affect audible fan or relay noises.
• Incorrectly configuring the "Grid Charge" setting or system timers can prevent Low Power Mode from activating or lead to unintended battery discharge.

Understanding Sunsynk's Low Power Mode for Classic, Acure, and Elite Inverters

Sunsynk's Low Power Mode is a feature designed for Classic, Acure, and Elite inverters to conserve battery energy during periods of low sunlight and low battery State of Charge (SOC). It acts as a 'hibernation' mode, allowing your inverter to reduce its own power consumption and stop powering non-essential loads. This is particularly useful in South Africa during extended periods of load-shedding or during winter months when solar generation is reduced.

How Low Power Mode Works

When Low Power Mode is enabled, the inverter will switch into this state under two specific conditions:

1. The battery SOC falls below the "Low Batt" threshold set in your inverter's battery settings.
2. There is no PV (solar) generation detected.

Once activated, the inverter stops powering non-essential or smart loads. Crucially, it also reduces the amount of power the inverter draws to power itself (quiescent current) down to almost nothing. The current will still pass through the inverter to power any load on the property, but it will essentially bypass the inverter to keep power loss to a minimum.

You can visually confirm that the inverter has entered Low Power Mode by checking the power and current readings above the inverter icon on the power flow chart on the inverter's LCD screen. These readings will show 0W/0A or very low values.

The inverter will automatically exit Low Power Mode when PV generation starts again, or if you manually deselect the Low Power Mode option. If you deselect it, it is advisable to reactivate "Grid Charge" in the Battery Settings menu to avoid over-discharging your batteries.

Configuring Low Power Mode and Low Noise Mode

The following table outlines the settings for both Low Power Mode and Low Noise Mode for Sunsynk Classic, Acure, and Elite inverters.

Low Power Mode Specifics

To enable Low Power Mode:

1. Via Sunsynk Connect: The "Low Power Mode<Low Batt" setting can be found towards the bottom of the Battery Settings menu.
2. On the inverter display: It can be found in Advanced Settings > Other.

For Low Power Mode to function correctly, the "Grid Charge" setting in the Battery Settings menu must be disabled. If "Grid Charge" is enabled, it will force a grid charge instead of allowing the inverter to enter Low Power Mode.

Additionally, system timer settings must be at least 1% lower than your "Low Batt" setting. If timers are set too high, they can prevent the system from entering Low Power Mode. Sunsynk recommends a buffer of around 5-10% difference between these values to prevent the system from frequently switching in and out of Low Power Mode.

If Low Power Mode is not selected, the inverter's self-consumption power will mainly come from the grid. If selected and the battery SOC is less than the "Low Batt" value, the inverter's self-consumption power will be drawn from both the grid and the battery simultaneously.

Low Noise Mode Specifics

Low Noise Mode is intended to be used when there is any form of radio interference coming from the inverter that affects other electrical appliances in your home, such as electric vehicle chargers, kitchen appliances, or television remotes. When enabled, the default switching speed of the internal electronics of the inverter changes from 15kHz to 20kHz.

It is important to note that Low Noise Mode does NOT change the audible noises from the inverter, such as fan sounds or relay clicks.

To enable Low Noise Mode:

1. Via Sunsynk Connect: The setting can be found in battery settings.
2. On the inverter display: The setting can be found in the advanced settings menu under the ‘Others’ tab.

For three-phase units, it is currently not possible to enable Low Noise Mode via Sunsynk Connect or the inverter display. This feature can only be enabled remotely by a Sunsynk technician, requiring a support ticket to be created.

What you can change yourself, and what you cannot

The settings for both Low Power Mode and Low Noise Mode, as described above, are generally considered owner-facing. This means you can adjust them yourself via the inverter display or the Sunsynk Connect app to optimise your system's performance and energy saving.

However, any settings related to grid protection, export limits, or fundamental electrical configuration should only be adjusted by a registered person. Changing these settings without proper authorisation and expertise can breach your connection agreement with Eskom or your municipality, invalidate your Certificate of Compliance (CoC), and potentially create unsafe conditions. Always consult a qualified solar installer for such adjustments.

If you encounter a fault code F23 when using Low Power Mode, this indicates a specific issue that requires further investigation. For detailed troubleshooting and mitigation steps for fault codes, please refer to our guide on Sunsynk Fault Codes Explained.

What the published sources do not tell you

While Sunsynk provides clear guidance on the functionality and configuration of Low Power Mode and Low Noise Mode, there are some aspects that the documentation does not fully detail:

• Specific Numeric SOC Values: The documentation provides relationships between settings like "Low Batt" and "Shutdown" (e.g., "5% buffer", "10% above Low Batt"), but it does not offer specific numeric State of Charge (SOC) values for different battery types or capacities. You will need to determine these based on your battery manufacturer's recommendations and your desired depth of discharge.
• Conflicting Battery Cut-off Recommendations: There are some conflicting recommendations regarding the buffer between "Low Batt" and "Shutdown" percentages. One source recommends "Low Batt% higher than the Shutdown % with at least a 5% buffer between them," while another states "Low Batt should be set 5% above Shutdown (recommended), or it can match the Shutdown value." Similarly, for "Restart," one source says it "should be higher than both Shutdown% and Low Batt%," while another suggests "Restart should be set 10% above Low Batt." This inconsistency means installers and owners must use their best judgement or consult with Sunsynk support for specific scenarios.
• Firmware-Specific Menu Paths: While general menu paths are provided (e.g., "Advanced Settings > Other"), the exact location or naming might vary slightly with different firmware versions. If you cannot find a setting, check your inverter's specific manual or Sunsynk Connect interface.
• No Load-Shedding Reserve Figure: The documentation does not provide a specific setting or recommendation for a "load-shedding reserve figure" for battery capacity, which could be useful for South African users planning for scheduled outages.
• Grid Start Floor: The documentation mentions that "the grid start% should be set lower than both Low Batt% and Shutdown%" but does not specify a 10% floor as is sometimes discussed in the community.