On the DC side, voltage drop and heating matter. MC4, polarity, length — undersized cable causes silent failure.
Planning
String, oversizing, cable
W and A clipping may be harmless — voltage isn't. Here are the planning articles with numbers.More numbers and realistic examples
If you want to know how to calculate cold Voc, or why the 400 W label isn't enough: registration brings new materials and calculators.
More panel watts than max solar input — on purpose. Summer clipping, but winter and cloudy weather is where the benefit lies.
Series: voltage rises, current does not. Parallel: current rises, voltage stays the same. Wrong choice = clipping or overvoltage.
The datasheet shows three numbers: watt, ampere, voltage. Two won't cause trouble. The third will — and faster in cold weather.