storagefaults.comstoragefaults.com

SMA•Sunny Island

Analysis by Marcus & Team

SMA Sunny Island Error 6603: Overload During Backup

Troubleshoot SMA Sunny Island Error 6603 overload in backup mode. Diagnostic steps, safety warnings, and prevention for residential solar+storage.

Frequently Asked Questions

•What is the continuous power rating of my SMA Sunny Island?

Refer to the Sunny Island's datasheet for its continuous power rating in AC watts. Ensure your connected loads do not exceed this rating.

•How do I perform a battery capacity test?

A battery capacity test involves discharging the battery at a controlled rate and measuring the time it takes to reach a predetermined voltage cutoff. Consult the battery manufacturer's documentation for specific testing procedures and safety precautions.

•What is NEC 690.12 and how does it affect my solar system?

NEC 690.12 outlines rapid shutdown requirements for PV systems. It mandates the ability to quickly de-energize the PV array in emergency situations. This may involve installing rapid shutdown devices (RSDs) that disconnect the PV array from the inverter.

Related questions

Loading related questions...

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.

← Back to list

Why This Happens:

Inaccurate Load Calculation: The actual power draw exceeds the inverter's continuous or surge rating.
Reactive Loads: High inrush current from motors or appliances exceeds the inverter's surge capacity.
Battery State of Charge (SOC) too low: Insufficient battery capacity to support the load.
Damaged Battery: Reduced capacity or high internal resistance limits available power.
Inverter Component Failure: Faulty capacitors, MOSFETs, or control circuitry.
Incorrect AC Wiring: Loose connections or undersized wiring causing voltage drop and increased current draw.

Important Warnings:

High DC voltage is present within the Sunny Island and battery system. Only qualified electricians should perform maintenance or repairs. Disconnect DC power before servicing. Adhere to NEC rapid shutdown requirements (NEC 690.12). Arc flash hazards exist. Use appropriate personal protective equipment (PPE), including insulated gloves and eye protection.

What to Look For:

SMA Sunny Island hybrid inverter displaying Error 6603 during whole-home backup operation. The inverter shuts down or reduces power output, failing to supply the expected load. System logs indicate an overload condition despite the apparent load being within the inverter's rated capacity. AC voltage and frequency may fluctuate prior to shutdown.

Solution:

1

Disconnect AC loads from the Sunny Island. Use a multimeter to confirm AC voltage is absent per NEC 706.15.
2

Verify Battery SOC: Check the battery's state of charge (SOC) using the Sunny Island's monitoring interface or a battery management system (BMS). Ensure SOC is above the minimum threshold for backup operation (typically 20%).
3

Measure AC Load: Use a clamp meter to measure the current draw of each AC load individually during startup and continuous operation. Calculate the total power consumption and compare it to the Sunny Island's specifications.
4

Inspect Battery Connections: Check battery terminals for corrosion or loose connections. Measure battery voltage and internal resistance. High resistance indicates a potential battery issue.
5

Conduct Inverter Self-Test: Run the Sunny Island's self-test diagnostics via the user interface (web portal or mobile app). Review error logs for additional clues.
6

Reduce Reactive Loads: Minimize use of appliances with high inrush currents (e.g., refrigerators, air conditioners) during backup operation.
7

Replace faulty components. Contact a qualified electrician for replacement of any component in the unit. Ensure NEC 690 is followed.

Technical Background:

The SMA Sunny Island is a battery-based inverter that provides backup power during grid outages. It performs DC/AC conversion to supply AC loads. Error 6603 indicates the inverter's internal overload protection has been triggered. This can be caused by excessive current draw, reactive loads, or internal component failure. The inverter monitors AC output voltage, current, frequency, and internal temperature. The MPPT algorithm is not relevant in backup mode, as the power source is the battery. Proper operation depends on accurate load calculation, correct battery sizing, and functional overload protection circuitry. NEC 690 covers PV systems, and NEC 706 covers energy storage systems (ESS).

Maintenance Tips:

Regularly update the Sunny Island firmware to ensure optimal performance and bug fixes.
Perform battery capacity tests periodically (e.g., every 6-12 months) to assess battery health and remaining capacity.
Monitor the Sunny Island's operating temperature and ventilation to prevent overheating.
Periodically inspect wiring connections for tightness and corrosion.
Implement load shedding strategies to reduce peak power demand during backup operation.