2. Voltage

What is the normal range of open-circuit voltage?

The open-circuit voltages of modules are measured under STC conditions (at a solar radiation of 1,000 W/m2 and a temperature of 25°C), while the open-circuit voltages measured by customers may be different from the voltage indicated on the nameplate because of influencing factors such as solar radiation, temperature and accuracy of instruments. Under normal service conditions, the temperature coefficient for open-circuit voltage is about -0.3(-)-0.35%/℃; therefore, the deviation in measured results is associated with the difference between actual temperature and 25°C at the time of measurement. Also, the deviation in open-circuit voltage caused by solar radiation must be within 10%. In sum, the difference between the open-circuit voltage for onsite testing and the actual range indicated on the nameplate should be calculated according to the actual measurement conditions, and generally should not surpass 15%.

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