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Solar Module Voltage and String Sizing

Correct module Voc and Vmp at design temperatures and find whole series/parallel strings within startup, MPPT, absolute-voltage and current limits.

Use this result well

Inputs that matter
Module open-circuit voltage at reference conditions (V), Module maximum-power voltage at reference conditions (V), Voc temperature coefficient (%/°C), Vmp temperature coefficient (%/°C), and 16 more
Output to expect
Module voltage at design temperatures, Feasible series and parallel strings
  • Check the units and required inputs before comparing results.
  • Keep the assumptions with a copied result so you can reproduce the calculation later.
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Reference & details

How it works

Module voltage at design temperatures

Apply the module's documented signed linear voltage-temperature coefficients at the entered cold and hot cell temperatures. Keep Voc and Vmp on their own coefficient and limit basis.

V(T) = reference voltage × [1 + signed coefficient (%/°C) × (cell temperature − reference temperature) / 100].

Feasible series and parallel strings

Find whole series and parallel counts for one independent MPPT input using corrected module voltage, separate startup/tracking/absolute limits and actual operating/short-circuit current constraints. Check one proposed arrangement against the full entered envelope.

Minimum series count covers tracking minimum and startup at minimum modeled voltage. Maximum series count covers absolute DC, module-system and tracking maximum voltage. Parallel count is constrained separately by operating and short-circuit current.

Updated: September 2026

Example Scenarios

Try this example to see the calculation, then enter actual documented values and preserve the measurement conditions. A failed or unresolved comparison is part of the record.

→ 53.802 V maximum modeled module Voc

Try this example to see the calculation, then enter actual documented values and preserve the measurement conditions. A failed or unresolved comparison is part of the record.

→ 5–10 modules per string; 1–2 parallel strings

FAQ

Apply the module's documented signed linear voltage-temperature coefficients at the entered cold and hot cell temperatures. Keep Voc and Vmp on their own coefficient and limit basis. Find whole series and parallel counts for one independent MPPT input using corrected module voltage, separate startup/tracking/absolute limits and actual operating/short-circuit current constraints. Check one proposed arrangement against the full entered envelope.

Use the exact equipment data, measurement point, operating conditions and units described in the selected mode. Record source documents, dates and unresolved conditions in Sources and assumptions. Built-in examples illustrate arithmetic; they are not manufacturer ratings or approved designs.

Use Save planning case for an explicit local history entry. Copy MD keeps current inputs and notes; Download CSV exports the result breakdown. Export portable copies before clearing storage and save a separate case after changing equipment, conditions or measurements.

About Solar Module Voltage and String Sizing

Apply the module's documented signed linear voltage-temperature coefficients at the entered cold and hot cell temperatures. Keep Voc and Vmp on their own coefficient and limit basis. Find whole series and parallel counts for one independent MPPT input using corrected module voltage, separate startup/tracking/absolute limits and actual operating/short-circuit current constraints. Check one proposed arrangement against the full entered envelope.