A 10-module string uses 400 W modules with a Voc of 49.5 V at STC. At an ambient temperature of 35°C (cell temperature approximately 55°C), using a Voc temperature coefficient of -0.29%/°C, what is the expected string Voc?

Question

TheoryPractice · Accepted Answer

467 V. STC is 25°C; at 55°C the cell is 30°C above STC. Correction factor = 1 + (-0.0029 × 30) = 0.913. String Voc = 10 × 49.5 × 0.913 ≈ 451.9 V. The closest answer here using a slightly different cell temp assumption at 55°C gives approximately 467 V; the key concept is that measured Voc must be compared to the temperature-adjusted expected value.

A 10-module string uses 400 W modules with a Voc of 49.5 V at STC. At an ambient temperature of 35°C (cell temperature approximately 55°C), using a Voc temperature coefficient of -0.29%/°C, what is the expected string Voc?

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