String design voltage windows

String design voltage windows are the upper and lower DC voltage boundaries used when a solar PV string is matched to an inverter, hybrid inverter or MPPT input. A string has to stay below the equipment's maximum DC input voltage, usually checked with cold open-circuit voltage, and within the MPPT operating range when the modules are warm or working at their maximum power point. The same design check is read alongside input current, short-circuit current, start-up voltage, module temperature coefficients and the number of modules in the string.