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Medium64%Moderate confidenceActive nowMPPT imbalanceINC-1063
Possible MPPT imbalance on Ring3 Inverter 2
Variation between active MPPT energy measurements is approximately 16.5%. This is an investigation candidate rather than a confirmed fault.
Apollo2_New · Ring3_Inverter2 · Started 06 Feb 2025, 09:00
Estimated energy loss
486kWh
Estimated financial loss
€53
Current loss rate
3.4kW
Duration
26 days
Recommended action
Compare string layout and orientation against the design documentation
Why SOL detected this
- MPPT 1 delivered 16.5% more energy than MPPT 2 over the period.
- The difference is stable across days, which points to a physical rather than weather cause.
- Comparable inverters at this site show a 3% to 4% spread.
- Total device output is still close to peer expectation, so the loss is moderate.
Most likely cause
One MPPT input is delivering consistently less energy than the others. Partial shading or a string level issue is the most likely explanation.
Other possible causes
- Different string capacities or orientations by design
- Partial shading across part of the day
- Module mismatch or degradation on one string
- A disconnected module or open connector
- String fuse or connector resistance
Recommended inspection
These steps become the technician checklist
- 1Compare string layout and orientation against the design documentation
- 2Inspect the strings on the lower producing MPPT for shading or soiling
- 3Measure string current and voltage under stable irradiance
- 4Check connectors and fuses on the affected input
Actual against expected power
Peer comparison for a representative day
Expected against actual power
Units: kW by time of day
What to notice: The dashed line is what comparable inverters produced at the same time. The shaded area is the actual output.