Solar Array String Sizing Calculator
Reviewed by Hamza Gujjar, Algorithm Architect & Software Developer
Last updated: July 28, 2026Solar Array String Sizing Calculator
Designing a solar array's wiring configuration? This calculator finds the valid range of panels per series string for your specific inverter.
Formula
Min Panels Per String = ceil(Inverter Min Voltage / Panel Vmp)
Max Panels Per String = floor(Inverter Max Voltage / Panel Vmp)
Example
A 40V (Vmp) panel, inverter accepting 200-500V input:
5 to 12 panels per string
Why Series-Wired Panels Add Their Voltages
Solar panels wired in series (a "string") add their individual voltages together while current stays the same - this is the standard wiring configuration used to reach an inverter's required input voltage range from many individually lower-voltage panels.
Why Staying Within This Range Is Critical
Exceeding the inverter's rated maximum input voltage can cause permanent damage to the inverter, particularly a real risk on cold mornings when panel voltage output actually increases above its rated Vmp - falling below the minimum voltage, meanwhile, simply prevents the inverter from operating at all.