🔌 Solar Array Wiring Calculator
Enter your panel specs and wiring layout to get the whole array's voltage, current and power.
Per-panel specs (from its datasheet), plus how many in series and parallel.
Array power
1800 W
Array Voc
120 V
Array Isc
18 A
Total panels
6
Wiring panels in series adds their voltages (Voc × number in series) while the current stays the same; wiring strings in parallel adds their currents (Isc × strings) at the same voltage. Total power is the sum of all panels. Check the array Voc against the maximum input voltage of your charge controller or inverter — cold weather pushes Voc higher, so leave margin. 🔒 In your browser.
How the solar array wiring calculator works
Solar panels combine like any DC sources: wiring them in series adds their voltages (the open-circuit voltage Voc times the number in a string) while the current stays the same, and wiring strings in parallel adds their currents (the short-circuit current Isc times the number of strings) at the same voltage. Total power is simply the sum of every panel's rated wattage. The tool multiplies out your series and parallel counts and shows array Voc, Isc and power so you can match them to your equipment.
The critical check is array Voc against the maximum input voltage of your charge controller or inverter — and remember Voc rises in cold weather (roughly +0.3%/°C below 25°C), so a cold sunny morning can push it well above the rated figure. Size for the coldest expected temperature, and make sure your controller can handle the array's short-circuit current too.
Frequently asked questions
How do I wire solar panels in series vs parallel?
Series (positive to negative down a string) adds voltage and keeps current the same; parallel (all positives together, all negatives together) adds current at the same voltage. Series suits higher-voltage MPPT controllers; parallel keeps voltage low but needs thicker cable for the higher current.
How do I calculate total array voltage?
Multiply a panel's open-circuit voltage (Voc) by the number of panels in a series string. Parallel strings don't add voltage. For 40 V panels three-in-series, the array Voc is 120 V.
How do I calculate array current?
Multiply a panel's short-circuit current (Isc) by the number of parallel strings. Panels in series share the same current. Two parallel strings of 9 A panels give 18 A.
Why does cold weather matter for array voltage?
Panel voltage rises as temperature falls — about 0.3% per °C below the 25°C rating. On a cold, clear morning the array Voc can exceed its rated value and damage a controller sized only for the nominal figure, so always leave headroom.
What is the difference between Voc/Isc and operating voltage?
Voc and Isc are the open-circuit voltage and short-circuit current — the maximum voltage (no load) and current (dead short). In normal operation the panel runs at its lower Vmp/Imp (maximum-power point). Voc/Isc are used for sizing limits; Vmp/Imp for expected output.