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SMA•Sunny Island

Analysis by Marcus & Team

SMA Sunny Island Humming Noise with Panasonic EverVolt

Troubleshoot humming noise in SMA Sunny Island hybrid inverter paired with Panasonic EverVolt. Diagnose power electronics, DC bus, and AC coupling issues.

Frequently Asked Questions

•What are the typical harmonic distortion limits for a Sunny Island inverter?

According to IEC 61000-3-2, the total harmonic distortion (THD) should typically be less than 5% for residential grid-tied inverters.

•How do I perform a firmware update on the Sunny Island?

Firmware updates are typically done through the SMA Sunny Portal or Sunny Explorer software, requiring an internet connection and access to the inverter's configuration interface. Refer to SMA's specific instructions.

•What is the recommended grounding impedance for a residential solar system?

NEC 250 typically requires a grounding impedance of less than 25 ohms, but local codes may have stricter requirements. Always consult with a qualified electrician.

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Marcus leads the technical research department at Storage Faults. Together with a team of systems analysts, he specializes in translating complex solar storage error codes into actionable diagnostic steps for the US market.

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Critical Safety Precautions:

Solar and energy storage systems involve potentially hazardous voltages and currents. Only qualified electricians should perform diagnostic and repair work on these systems. Always follow proper lockout/tagout procedures and wear appropriate personal protective equipment (PPE), including arc flash-rated clothing and gloves. Never work on live circuits. Ensure compliance with NEC 690 rapid shutdown requirements.

Solution:

1

Power down the entire solar and storage system following NEC 690 rapid shutdown procedures and the manufacturer's recommended disconnection sequence. Verify zero voltage at the DC disconnect and AC disconnect points using a calibrated multimeter.
2

Visually inspect the SMA Sunny Island inverter for any signs of physical damage, loose connections, or component discoloration. Pay close attention to the inductor coils and capacitors within the power electronics section.
3

Use a clamp meter to measure the AC output current and DC input current of the inverter while the Panasonic EverVolt battery is at various SOC levels. Record the harmonic distortion levels using a power quality analyzer.
4

Use an IR thermometer to measure the temperature of the inductor coils and capacitors within the inverter while it is operating. Elevated temperatures may indicate component stress or impending failure.
5

Check the grounding connections throughout the solar and storage system to ensure proper bonding and grounding according to NEC 250 requirements. Verify grounding impedance using a ground resistance tester.
6

Review the inverter's configuration settings and firmware version. Compare the settings with the recommended configuration for Panasonic EverVolt systems as specified by SMA. Update the firmware to the latest version if necessary.
7

If the humming noise persists, contact SMA technical support for further assistance and potential warranty claims.

How It Works:

The SMA Sunny Island is a battery-based inverter responsible for DC/AC conversion and grid synchronization. When the Panasonic EverVolt battery is fully charged, the Sunny Island manages power flow to maintain the battery's SOC and potentially export excess energy to the grid. The humming noise can originate from the inverter's internal components, such as the inductor coils in the DC-DC converter or AC output filter. Power electronics switching frequencies and harmonic currents generated during the charging or discharging process can induce mechanical vibrations in these components, resulting in audible noise. AC coupling between the inverter and the EverVolt also introduces complex impedance interactions.

What to Look For:

Audible humming noise emanating from the SMA Sunny Island inverter, specifically when the Panasonic EverVolt battery is at or near full state of charge (SOC). The noise may fluctuate in intensity and frequency, potentially indicating harmonic distortion or component resonance. The noise is perceptible within the residential environment during quiet periods.

Pro Tip:

Use SMA Sunny Explorer software to access advanced diagnostic information from the Sunny Island inverter, including real-time voltage and current waveforms, harmonic distortion levels, and fault logs. This software can help pinpoint the source of the humming noise by analyzing the inverter's internal operating parameters.

Possible Causes:

Excessive harmonic distortion in the AC output current from the Sunny Island inverter.
Component resonance within the inverter's DC-DC converter or AC output filter due to specific operating conditions (e.g., full battery SOC).
Loose or damaged inductor coils within the inverter's power electronics.
DC bus voltage ripple affecting the inverter's operation and causing noise.
Grounding issues leading to circulating currents and electromagnetic interference (EMI).
Incompatibility or configuration problems between the Sunny Island and Panasonic EverVolt system, requiring firmware or parameter adjustments.

Maintenance Tips:

Periodically inspect the inverter for signs of physical damage or loose connections.
Monitor the inverter's operating parameters (voltage, current, temperature) using the SMA monitoring portal.
Check and tighten all electrical connections as needed.
Ensure proper ventilation around the inverter to prevent overheating.
Schedule a licensed technician inspection of the system every 3-5 years, including a thorough electrical test and component evaluation.