SMA Common Field Failures¶
EXPANDING
This section documents field-confirmed SMA failure modes encountered in Wadadli Solar operations. Each entry will grow as real cases are documented.
String Performance Degradation¶
Observation: Production trending downward over months/years. No fault codes.
Causes: - Panel degradation (normal aging — typically 0.5%/year) - Soiling (bird droppings, pollen, dust accumulation) - Shade creep (tree growth, new structure) - MPPT accuracy degradation in aging inverter
Diagnosis: Compare actual vs. expected production using PVWatts or site's historical baseline. Inspect for soiling and shade.
Ground Fault / GFDI Fault¶
Observation: GFDI fault code, system offline.
Causes in aging systems: - Degraded wiring insulation (UV, heat, animal damage) - Water intrusion at junction boxes or conduit - Panel delamination exposing live conductors
Diagnosis: String isolation testing — disconnect strings one at a time to identify faulted string. Use insulation resistance tester if available.
Fan Failure¶
Observation: Inverter trips off during hot summer afternoons, restarts when cooler.
Cause: Cooling fan failed — inverter overheats under load.
Diagnosis: Listen for fan noise during operation. Feel case temperature. Check inverter event log for over-temperature events.
Resolution: Fan replacement — SMA spare parts or equivalent.
Capacitor Aging¶
Observation: System is older (10+ years), production efficiency declining slowly. No clear fault codes.
Cause: Electrolytic capacitors inside the inverter degrade over time, reducing efficiency.
Note: Not directly field-diagnosable. Include in aging system reporting and flag for replacement planning.
DC Connector Oxidation¶
Observation: String underperforming. No fault codes but consistent low output.
Cause: MC4 connectors at junction boxes or roof connections have oxidized, increasing resistance.
Diagnosis: Thermal imaging of connections. Manual connector inspection — green/black oxidation visible.
Resolution: Clean or replace connectors. Use proper MC4 tools — do not force mismatched connectors.