A string's measured Voc is 2.5% lower than the temperature-corrected expected value. Which of the following is the LEAST likely explanation?

A string's measured Voc is 2.5% lower than

Multiple choice — select the best answer

AOne module has a failed bypass diode conducting current
BThe irradiance on the array is slightly below the assumed value
COne module connection has high series resistance
DOne module in the string is operating at a lower-than-rated Voc due to manufacturing tolerance

✓ Correct answer: B. The irradiance on the array is slightly below the assumed value High series resistance in a module connection does not reduce Voc; Voc is determined by the photovoltaic junction voltage and is relatively insensitive to series resistance (which affects current-carrying performance at Isc and Pmax). The other options all directly reduce open-circuit voltage.

.q-expl{display:block!important}.q-opt[data-idx="1"]{border-color:#16a34a;background:#f0fdf4}.q-opt[data-idx="1"] .oltr{background:#16a34a;color:#fff}.q-opt{cursor:default!important;pointer-events:none}

Keep practising. Use the free Solar PV NABCEP PDF, watch the YouTube walkthrough, or unlock all 10 web questions with timed mock exams.

Free PDF Video walkthrough

Topic: Commissioning & O&M

← Previous Next → 🎲 Random question ↩ Back to all questions

Keep practising

A string's measured Voc is 2.5% lower than the temperature-corrected expected value. Which of the following is the LEAST likely explanation?

Related questions — Commissioning & O&M

Free practice here. Timed mocks when you are ready.