Match the module electrically before considering branch count
Begin with the exact PV module datasheet and the exact regional microinverter model. Check module open-circuit voltage at the site’s cold design temperature, operating voltage, short-circuit current and current at maximum power against the microinverter’s input limits. A panel being within a marketing wattage range does not prove electrical compatibility. Temperature corrections and bifacial current gains can change the result.
Expect some DC oversizing, but quantify clipping
Modern modules are often rated above the microinverter’s maximum AC output. That can be intentional, because modules rarely operate at nameplate power for long periods, but excessive oversizing can create avoidable clipping. Compare the module’s expected operating conditions with the microinverter’s MPPT range and AC ceiling rather than using a single DC-to-AC ratio. See Melnti’s inverter sizing and clipping guide.
Branch-circuit limits are region and model specific
The number of microinverters allowed on one branch depends on each unit’s maximum AC output current, cable system, breaker size, continuous-load rules and the manufacturer’s regional installation instructions. Do not copy a branch count from another country or another IQ8-class model. Record the exact regional SKU and the table or manual used for the calculation.
Grid profile and communications are part of compatibility
Commissioning normally includes the correct utility grid profile, gateway communications and firmware. Verify that every microinverter reports, that the array map matches physical module positions and that no unit remains on an incorrect grid profile. If hardware or firmware versions differ within an expanded system, confirm the manufacturer explicitly supports the combination.
Keep AC and DC evidence together
The commissioning pack should contain the module datasheet, microinverter datasheet, branch layout, conductor and breaker details, array map, grid-profile record and serial numbers. The commissioning and handover checklist provides a broader record structure.
Architecture is only one decision
Microinverters can offer module-level conversion and monitoring, while string systems centralise conversion. Neither architecture is automatically better for every roof. Compare service access, shading, rapid-shutdown requirements, battery plans and lifetime replacement strategy using the microinverter versus string-inverter comparison.