Screening use onlyResults are educational estimates. They are not verified for construction, equipment selection, or permit submission.· 2 registered heuristic groups (H-002 · H-018)Why

These calculators are undergoing a correctness audit against primary standards. Part of the logic still rests on engineering rules-of-thumb rather than rules traced to a dated edition of a code, and some published citations do not yet match the rule the code actually applies. Known defects are being fixed in sequence.

Treat every number here as a starting estimate to be checked, never as a design decision. Anything that will be built, energised, or submitted to an authority must be independently calculated and sealed by a licensed engineer who takes responsibility for the result.

Audit status: in progress · Assurance level: screening · Not for permit use

Rule-of-thumb decisions on this calculator

H-002 · screening only
Decision points: panel technology preset · battery chemistry preset · inverter DC/AC ratio and typical-efficiency guidelines · per-item system-loss preset · latitude tilt rule of thumb · market size catalogs and the 400 W reference module prefilled into the forms
Solar presets stand in for module, battery and inverter data the caller has not supplied; the engines label them as presets in their output, but they remain generic technology figures rather than product data.
Permit gate: block
H-018 · forbid permit
Decision points: DC/AC target range from the built-in guidelines · 5% cold-Voc margin on maximum input voltage · 5% hot-Vmp margin on the MPPT minimum · fixed 600 V and 150 V string-voltage warnings · single-MPPT topology assumed when the MPPT count is unstated · unequal tracker lengths permitted when the matching rule is unstated
Module coefficients, NOCT and site design temperatures are now required, but inverter voltage and current envelopes still rest partly on built-in ratios and margins, and the two topology assumptions — single MPPT, unequal trackers allowed — are disclosed in the result rather than refused.
Permit gate: block

Screening use only — Results are educational estimates. They are not verified for construction, equipment selection, or permit submission.

These calculators are undergoing a correctness audit against primary standards. Part of the logic still rests on engineering rules-of-thumb rather than rules traced to a dated edition of a code, and some published citations do not yet match the rule the code actually applies. Known defects are being fixed in sequence.

Treat every number here as a starting estimate to be checked, never as a design decision. Anything that will be built, energised, or submitted to an authority must be independently calculated and sealed by a licensed engineer who takes responsibility for the result.

Audit status: in progress · Assurance level: screening · Not for permit use

Rule-of-thumb decisions on this calculator

H-002 · screening only
Decision points: panel technology preset · battery chemistry preset · inverter DC/AC ratio and typical-efficiency guidelines · per-item system-loss preset · latitude tilt rule of thumb · market size catalogs and the 400 W reference module prefilled into the forms
Solar presets stand in for module, battery and inverter data the caller has not supplied; the engines label them as presets in their output, but they remain generic technology figures rather than product data.
Permit gate: block
H-018 · forbid permit
Decision points: DC/AC target range from the built-in guidelines · 5% cold-Voc margin on maximum input voltage · 5% hot-Vmp margin on the MPPT minimum · fixed 600 V and 150 V string-voltage warnings · single-MPPT topology assumed when the MPPT count is unstated · unequal tracker lengths permitted when the matching rule is unstated
Module coefficients, NOCT and site design temperatures are now required, but inverter voltage and current envelopes still rest partly on built-in ratios and margins, and the two topology assumptions — single MPPT, unequal trackers allowed — are disclosed in the result rather than refused.
Permit gate: block

CALC 17 · SOLARPREVIEW

Solar Inverter Sizing Calculator

Calculate the optimal inverter size based on your PV array configuration. Includes temperature-corrected voltage calculations and DC/AC ratio optimization.

Solar Design Workflow

Panel SizingPanels

2Inverter SizingInverter

3Battery BankBattery

4String ConfigStrings

5ROI AnalysisROI

Inverter Sizing · Advanced Preview

Available free during the correctness audit. Results remain screening-only unless the result itself states a stronger assurance level.

PANEL SPECIFICATIONS

Module (CEC library)

Panel Presets (Quick Select)

Generic starting values, not a datasheet — a preset supplies Voc, Vmp, Isc, Imp and βVoc only; βVmp and NOCT still come from your module datasheet.

Voc (V)

V

Vmp (V)

V

Isc (A)

A

Imp (A)

A

MODULE TEMPERATURE PARAMETERS

Temp Coefficient Voc — βVoc

%/°C

Negative value, as printed on the datasheet. Filled from the CEC library or a generic preset on selection.

Temp Coefficient Vmp — βVmp

%/°C

Negative value. Not in the CEC library — γPmax is a different quantity, so take βVmp from your module datasheet.

NOCT

°C

Nominal operating cell temperature. Filled from the CEC library on selection.

These three come off the module datasheet and set the temperature-corrected string voltages. Leave one blank and the calculation is refused by name rather than completed from an assumed value.

String Configuration

Panels in Series

Number of Strings

Total Panels:20

System Size:— (module wattage not stated)

Min Temperature (°C)

°C

Record-low site temperature — sets cold Voc. Not pre-filled.

Max Temperature (°C)

°C

Maximum site temperature — sets hot Vmp. Not pre-filled.

Inverter Type

Grid Voltage (V)

Grid Phases

Invalid Input

minTemp is required — the record-low site temperature sets the cold Voc that the inverter must withstand. It is not replaced with a default.

INVERTER SIZING RESULTS

— AWAITING INPUT —

Enter your panel specifications and string configuration to get inverter recommendations.

DC/AC RATIO GUIDE

1.2

Optimal - balanced performance and cost

1 - 1.15

Conservative - minimal clipping, higher upfront cost

1.3 - 1.5

Aggressive - lower cost, some clipping on peak days

Related Calculators

Solar Panel Sizing

System size from energy needs

String Configuration

Series/parallel panel layout

Battery Bank Sizing

Off-grid/hybrid storage