Shallow IV slope near Voc

On a measured IV curve, the part between the maximum power point and Voc slopes less steeply than expected. A normal curve has a near-vertical downward leg. How steep it is depends on the cell technology and how the module was made. A less steep slope near Voc points to higher series resistance in the circuit. This also lowers the fill factor and maximum power. Possible causes include damaged, faulty or undersized PV wiring, poor connections between modules or within the array, and higher series resistance inside the module. Inside the module, the resistance can rise at the cell interconnects or junction box because of degradation, corrosion, loose solder joints or manufacturing error. Long cable runs also flatten this slope. Either adjust the model for the cables or repeat the test closer to the array. Before blaming a fault, rule out measurement errors, instrument setup problems and wrongly entered module or string data. An IR scan can help find high-resistance faults that cause this signature.

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• sentence 5: support check: partial - The passages give cell interconnects and junction box with degradation, corrosion or manufacturing error, and u5 mentions slack joints, but not loose solder joints specifically. -->