Applicable Systems
Sunny Boy
Symptoms
Power stage overload. The inverter power stage is overloaded beyond its thermal and electrical limits.
Possible Causes
- PV array oversized for inverter AC rating
- Grid voltage low causing high current for same power
- Power stage IGBT degradation reducing capacity
- Inverter operating at high ambient temperature with derating not applied
Troubleshooting Steps
- Step 1: Check the equipment status and fault indicators to confirm the active fault code
Fault indicator or HMI displays code 6602 as active - Step 2: Verify all electrical connections, wiring harnesses, and connector seating
All connections secure, no corrosion, loose pins, or damaged wires - Step 3: Check the system diagnostic buffer or event log for detailed fault information
Diagnostic buffer shows the specific fault cause and timestamp - Step 4: Verify power supply stability and environmental conditions
Power supply stable, environment within specifications - Step 5: Restart the equipment or power-cycle the control system
Equipment restarts and enters normal operating state - Step 6: Contact manufacturer support if the fault persists after all checks
Support provides specific troubleshooting guidance
How to Reset
To reset: 1) Identify and fix the root cause described in the fault symptoms. 2) Press RESET on the HMI or controller, or power-cycle the equipment. 3) If the fault recurs, contact manufacturer service. Caution: Document the fault code and context before resetting.
Frequently Asked Questions
- Q: What does fault code 6602 mean on the SMA Sunny Boy?
Fault 6602 on the SMA Sunny Boy indicates: Power stage overload. The inverter power stage is overloaded beyond its thermal and electrical limits. Refer to the equipment manual and manufacturer support for specific troubleshooting steps.
- Q: Can I continue operating the equipment with fault 6602 active?
No. The equipment has detected a fault condition and has taken protective action (typically stopping or derating). Continuing to operate without fixing the root cause may cause further damage. Always investigate and fix the fault before resuming operation.
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Source: SMA Sunny Boy Inverter Installation and Operation Manual, SMA Official Documentation
Category: PLC & VFD
Published: 2026-10-10
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