Solar panel series vs parallel wiring
How you interconnect panels decides what your charge controller sees: series stacks voltage at constant current, parallel stacks current at constant voltage. Total watts are identical either way - the engineering lives in the voltage/current split.
Neither is universally better. String design is a negotiation between your controller's input window, your wire run length, your site's cold extreme, and your shade.
How it works
Series: string voltage is the sum of panel voltages (times the cold-weather correction), current stays at one panel's worth. Higher voltage means less current for the same power - smaller wire over long runs - but the whole string must stay under the controller's voltage limit on the coldest morning, and shade on one panel drags the string.
Parallel: voltage stays at one panel's worth, currents add against the controller's input limit, and each string needs its own overcurrent protection above a couple of strings. Hybrid series-parallel layouts - a few panels in series per string, strings in parallel - are how most real arrays balance the constraints.
Common questions
Which produces more power?
Neither - watts are watts. MPPT controllers often harvest somewhat better from higher-voltage strings, especially in low light, but the panels' total rating is the ceiling either way.
Which handles partial shade better?
Parallel. A shaded panel in a parallel array mostly just subtracts its own output; a shaded panel in a series string can throttle the whole string. If your site has moving shade, favor shorter strings.
Can I mix different panels in one array?
Within a series string, mismatched current wastes the stronger panel; across parallel strings, mismatched voltage does. Mixing works best as separate strings on separate MPPT inputs. The checks flag mismatch when you try it.
Why do parallel strings need fuses?
With several strings in parallel, a faulted string can sink the combined current of all its healthy siblings. String fusing protects the wiring of the one that failed.
Try different series-parallel layouts in the builder and watch the voltage, current, and mismatch checks respond, formulas visible.
Open the builderThese guides are educational and qualitative on purpose - the numeric answers depend on your exact components, and the builder computes them with every formula shown. Always verify a final design with a licensed professional.