Inputs
String design options
Enter your specs and click Calculate.
Notes.
Effective max VOC = controller max input V × (1 − cold-weather margin).
Cold temperatures raise panel VOC above its rated value, so the margin keeps the array safe at the coldest expected operating temperature.
Total array wattage may exceed the controller's rated input by the “allowed PV oversize” setting (controllers clip excess current at MPPT).
String fuse / breaker recommendations follow the common rule of thumb: string fuses required at 3+ parallel strings.
This tool ignores Isc, temperature coefficients, wire run length, and code-specific requirements — verify against the panel datasheet, controller manual, and local electrical code before installation.