AUWiring

PV array power calculator

Estimate PV array kW from entered module rating, modules per string, parallel strings and derate factor for Australian solar planning records.

  • Calculator
  • Solar and battery
  • Australia
Use the PV array, string group or inverter input reference.
W
Enter the module rating from the product record.
modules
Enter the module count in each series string.
strings
Enter the number of parallel strings in the array record.
factor
Enter 1 for no derate or a lower project factor when needed.
kW
Enter the inverter AC capacity used for the DC/AC ratio handoff.
Array kW = module W x modules per string x parallel strings / 1000; Derated array kW = Array kW x derate factor; DC/AC ratio = derated array kW / inverter AC kW
  • Modules per string and parallel strings are entered whole-number counts.
  • Derate factor is entered by the user.
  • DC/AC ratio is a handoff value, not an inverter approval.
  • String voltage and string current remain separate checks.
Formula variables
VariableMeaningUnitUse
WmoduleModule ratingWEntered module power rating.
NsModules per stringcountEntered number of modules in each series string.
NpParallel stringscountEntered number of parallel strings.
NtotalTotal modulescountModules per string multiplied by parallel strings.
ParrayRaw array powerkWModule rating multiplied by total modules and divided by 1000.
FderateDerate factorfactorEntered project derate applied to raw array kW.
PderatedDerated array powerkWRaw array power multiplied by derate factor.
PinvInverter AC capacitykWEntered inverter AC capacity used for ratio comparison.
RatioDC/AC ratioratioDerated array kW divided by inverter AC kW.
More

PV array power calculator technical guide

Estimate PV array kW from entered module rating, modules per string, parallel strings and derate factor for Australian solar planning records.

Use this page when a PV design record needs a clear array power value from entered module rating and string counts. It gives raw array kW, derated array kW, total module count and a DC/AC ratio handoff. It does not approve the module layout or inverter selection.

PV Array Power Boundary

This calculator does not approve module layout, inverter suitability, string voltage, string current, isolator selection, export settings or installation compliance. It records arithmetic from values entered by the user.

PV array power boundaries
TaskUse this page?Why
Total module countYesThe page multiplies modules per string by parallel strings.
Raw and derated array kWYesThe page owns module W and derate arithmetic.
String voltageNoUse the PV string voltage calculator.
String currentNoUse the PV string current calculator.
Inverter approvalNoProduct listings, DNSP requirements and manufacturer data remain external.

Input Checklist

PV array power input sources
ValueWhere it normally comes fromStop if
Module ratingDatasheet, module schedule or product recordThe module W basis is unclear.
Modules per stringString layout recordIt has not been checked against string voltage.
Parallel stringsArray layout recordIt does not match the current or inverter record.
Derate factorProject assumption, modelling note or reviewer inputIt is copied without source.
Inverter AC capacityInverter schedule or product recordThe capacity basis is not the same as the sizing worksheet.

Review Workflow

  1. Name the PV array, string group or inverter input record.
  2. Enter module W from the product or schedule record.
  3. Enter modules per string and parallel strings from the layout record.
  4. Enter derate factor as 1 for raw array power or a lower source value when required.
  5. Enter inverter AC capacity if the DC/AC ratio handoff is useful.
  6. Read total modules, raw array kW and derated array kW before using the ratio.
  7. If the ratio is high, review inverter product data, export settings and project assumptions.
  8. Carry array kW into inverter sizing only as an entered planning value.

Worked Records

PV array power examples
SituationInputsResultRecord use
Thirty-module array440 W modules, 10 per string, 3 strings, 0.95 derate13.2 kW raw, 12.54 kW deratedHandoff to inverter sizing.
High ratio review550 W modules, 12 per string, 4 strings, 15 kW inverter26.4 kW raw, 1.76 DC/AC ratioReview product and export assumptions.
Small array handoff415 W modules, 8 per string, 2 strings, 0.9 derateSmall planning recordKeep array kW visible for downstream worksheets.

Australian Context

PV array power records in Australia sit beside AS/NZS 5033 string and array context, AS/NZS 4777 inverter context, DNSP export conditions, product listings and manufacturer instructions. This page keeps the quantity arithmetic visible while leaving those external requirements outside the calculator.

Stop Points

  • Module rating or derate factor has no source record.
  • String count has not been checked with PV string voltage.
  • Parallel string count does not match current or inverter records.
  • DC/AC ratio is being treated as inverter approval.
  • The result is being used as installation compliance approval.

Thirty-module array record

A 10S3P array uses 440 W modules and a 0.95 derate factor before inverter ratio review.

Reference
PV-ARRAY-1
Module rating
440 W
Modules per string
10
Parallel strings
3
Derate factor
0.95
  1. Total modules30
  2. Raw array power13.2 kW
  3. Derated array power12.54 kW
Derated array power12.54 kW

DC/AC ratio is 1.254 on the entered inverter capacity.

The derated array kW is ready to carry into inverter sizing, subject to product and string checks.

  • Module rating is entered from product data.
  • Derate factor is entered by the user.
  • String voltage and product suitability are separate checks.

High ratio review

A larger array is compared with a 15 kW inverter to show when DC/AC ratio review is expected.

Reference
PV-ARRAY-REVIEW
Module rating
550 W
Modules per string
12
Parallel strings
4
Derate factor
1
  1. Total modules48
  2. Raw array power26.4 kW
  3. Derated array power26.4 kW
Derated array power26.4 kW

DC/AC ratio is 1.76 on the entered inverter capacity.

The DC/AC ratio is high, so inverter product data, export settings and project assumptions need review.

  • The high module count is intentional.
  • The derate factor is 1 for the comparison case.
  • No inverter approval is made.

Small array handoff

A smaller 8S2P array is recorded before its kW value is used in downstream worksheets.

Reference
PV-ARRAY-SMALL
Module rating
415 W
Modules per string
8
Parallel strings
2
Derate factor
0.9
  1. Total modules16
  2. Raw array power6.64 kW
  3. Derated array power5.98 kW
Derated array power5.98 kW

DC/AC ratio is 0.996 on the entered inverter capacity.

The array power is a clear planning value, while string voltage and current remain separate tasks.

  • Modules per string is entered as a whole number.
  • Parallel strings are entered by the user.
  • Australian product and installation context remains external.

Questions

Does this approve a PV module layout?

No. It estimates array power from entered values only. String voltage, product limits and installation requirements remain separate checks.

Should derate factor be 1?

Use 1 when recording raw module power, or enter a project derate factor when the source record requires it.

Can this feed inverter sizing?

Yes. Use the calculated array kW as a planning value, then review inverter sizing separately.

Why include inverter capacity?

It gives a DC/AC ratio handoff so high entered ratios can be reviewed before product decisions.