Solar Array Sizer

Calculate solar array size based on panel specs and system voltage.

Inputs

V

A

V

%

Typically 125% for NEC compliance.

Outputs

Max Panels per String
10
panels
Number of Strings (Example)
4
strings
Array Open Circuit Voltage
455
V
Array Short Circuit Current
36.8
A

System Diagram

System Schematic

4 string(s)10 panels/stringCombiner BoxTo Inverter455V / 36.8A

Details

Description

This tool helps determine the maximum number of solar panels that can be connected in a series string without exceeding the voltage limits of your inverter or charge controller. It also provides an example of total array voltage and current.

Design Principles

1. Safety First: The primary constraint is the maximum input voltage of the inverter/controller. Exceeding this can damage the equipment. 2. NEC Compliance: The National Electrical Code requires a safety factor (typically 1.25) to account for increased voltage in cold weather (the "temperature coefficient" effect). 3. String Parallelism: When connecting multiple strings in parallel, each string must have the identical number of identical panels to avoid current backflow and potential damage.

Relevant Equations

Panels per String = Floor(Max System Voltage / (Panel Voc * Safety Factor)) Array Voc = Panels per String * Panel Voc Array Isc = Number of Strings * Panel Isc