MPPT imbalance
Unequal power across the MPPT inputs of a single inverter.
MPPT imbalance is when the maximum-power-point trackers on one inverter deliver materially different power despite seeing the same conditions. It points to uneven string lengths, mismatched orientation, partial shading on one tracker, or a tracker hunting around its setpoint.
Symptoms
- One MPPT input consistently lower than the others on the same inverter.
- Tracker output oscillates ("hunting") instead of settling at a stable point.
- Imbalance appears or worsens at specific sun angles (shading signature).
SCADA signatures
- Per-MPPT power spread above the configured tolerance during clear sky.
- Voltage/current oscillation on one tracker = MPPT hunting.
- Time-of-day-locked imbalance = geometric shading rather than hardware.
Root cause
Coarse MPPT imbalance usually reflects design (different string counts, split orientations) or developing shading; hunting reflects a control-loop or firmware issue, or a marginal string the tracker cannot resolve cleanly.
Financial impact
A few percent of inverter output lost across the high-irradiance season, plus accelerated wear when a tracker hunts continuously. Catching a hunting tracker early avoids both the yield loss and the firmware truck roll.
How NuraVolt detects it
NuraVolt evaluates per-MPPT power against the inverter cohort and a geometric shading model, separating designed imbalance from developing faults. A dedicated oscillation detector flags hunting from the voltage/current time series.
Frequently asked questions
See also
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