Introduction #

How to wire solar panels in series and parallel: series multiplies voltage (Voc/Vmp × N_series); parallel multiplies current (Isc/Imp × N_parallel). Combined series-parallel (e.g. 2S2P) raises both. Use this method for commercial string layout, then compute live values in the Solar Panel Series Parallel Calculator.

Best for: EPCs and technicians planning string Voc/Isc into MPPT or inverter windows.

Not ideal for: AC mains wiring, or DIY tutorials without datasheets.

Series vs parallel (rules) #

Conclusion: Series → voltage; parallel → current; power scales with both counts (ideally).

Connection Voltage Current
Series (N_s) Voc × N_s , Vmp × N_s ≈ module Isc / Imp
Parallel (N_p) ≈ module Voc / Vmp Isc × N_p , Imp × N_p
Series-parallel Voc × N_s Isc × N_p

CTA: Enter Voc/Isc and counts in the Series Parallel Calculator on the Solar calculator hub.

Worked example (2S2P) #

Given: Voc 49 V, Vmp 41 V, Isc 11 A, Imp 10.2 A, layout 2S2P.

Result Value
String Voc 49 × 2 = 98 V
String Vmp 41 × 2 = 82 V
Array Isc 11 × 2 = 22 A
Array Imp 10.2 × 2 = 20.4 A
Power ≈ 41 × 10.2 × 2 × 2 ≈ 1.67 kW

Next: cold Voc + MPPT current in How to Size a Solar Charge Controller → MPPT Sizing; DC cable in How to Size Solar DC Cable.

Practical wiring notes #

Conclusion: Homogeneous modules and matched string lengths reduce mismatch.

  • Same model/bin in a parallel group
  • Fusing / combiner rules per code and OEM
  • Check cold Voc before closing series count
  • Label polarity; MC4 assembly is out of scope here

Common mistakes #

  1. Mixing series and parallel mentally — voltage and current do not both rise in pure series.
  2. Ignoring cold Voc for winter mornings.
  3. Paralleling unequal string voltages.
  4. Sizing cable from Imp only.

Next steps #

  1. Series Parallel Calculator.
  2. MPPT vs PWM if choosing topology.
  3. MPPT Sizing · Cable Size.
  4. Array energy: How to Size a Commercial Solar Array.

Assumptions and disclaimer #

STC values ignore mismatch and temperature until you apply corrections. Planning only—follow OEM and code for installation.

FAQ #

How do I wire solar panels in series and parallel?

Series connects positive to negative to raise voltage; parallel connects like terminals to raise current. Combinations (e.g. 2S2P) do both.

How do I calculate string voltage?

String Voc = module Voc × modules in series. Example: 49 V × 2 = 98 V STC.

How do I calculate array current?

Array Isc = module Isc × parallel strings. Example: 11 A × 2 = 22 A.

Which tool should I use?

The Solar Panel Series Parallel Calculator for Voc/Isc layouts.