Start with the energy path
PV cells produce direct current (DC). A conventional module sends DC through a string to a string or hybrid inverter. An AC module combines a PV module with a microinverter, so conversion happens at the module. A third common arrangement adds DC optimisers at module level while retaining a shared inverter.
Those labels describe architecture. They do not, by themselves, settle yield, safety, reliability, cost or battery suitability.
What changes in the field
- Tracking: check which modules share each maximum-power-point tracker (MPPT). String inverters may have several MPPT inputs; microinverters and optimisers move control closer to each module.
- Shade and mismatch: module-level electronics can reduce interaction between modules, but the result depends on shade geometry, bypass behaviour, product controls and wiring.
- Fault impact: a shared inverter can stop its connected array when it is unavailable. Module-level systems distribute conversion, but may still share branch circuits, communications, gateways or grid interfaces.
- Access: a wall-mounted inverter is generally reached without lifting modules. Module-level electronics place more serviceable equipment on the roof.
- Monitoring: confirm what the installed licence, gateway and portal actually expose. Architecture alone does not guarantee owner or installer access to module-level data.
Battery coupling needs a system check
Batteries store DC, but that fact does not make every DC-coupled proposal preferable. AC- and DC-coupled systems use different conversion, control and backup paths. For a new system or retrofit, record:
- the exact inverter, battery and gateway models;
- which equipment remains energised in backup mode and which loads are supported;
- charge, discharge, PV and export limits;
- compatibility and warranty conditions; and
- the network-approved connection arrangement.
Fast selection check
- Map roof faces, recurring shade and usable module positions.
- Draw the proposed strings, MPPT allocation and conversion points.
- Confirm cold-voltage, current and power limits from the exact module and inverter documents.
- Decide what monitoring and fault isolation the operator actually needs.
- If storage or backup is proposed, check that exact operating path rather than relying on “AC” or “DC” shorthand.
- For an Australian SRES installation, verify the exact module and inverter models are on the approved product lists and within their listing dates.
There is no topology that wins every site. Compare a documented design against the roof, loads, service plan and current connection requirements.