LIVE design intermediate 5 min read
AC coupling vs DC coupling
When to AC-couple (retrofit) versus DC-couple (new build) a Deye hybrid — and the trade-offs that matter on AU sites.
Updated 1 June 2026
Deye hybrids can do both. The right choice usually comes down to whether there’s existing solar.
DC coupling (new installs)
PV strings connect straight into the hybrid’s MPPT inputs. One inverter does PV + battery + grid.
- Best efficiency — solar charges the battery through a single DC→DC step.
- Simplest BOM, one device to commission.
- PV array size is bound by the model’s MPPT count and max PV input — check the product’s spec table.
AC coupling (retrofits)
The hybrid sits alongside an existing grid-tied PV inverter; the legacy inverter’s AC output is sensed and used to charge the battery. Every Deye hybrid in this hub lists “AC couple to retrofit existing solar” as a feature.
- Keeps the customer’s existing solar — no re-stringing, no replacing a working inverter.
- Solar→battery goes AC→DC, so it’s a little less efficient than DC coupling.
- Mind the ratio: keep AC-coupled PV within the hybrid’s charge capability so it can absorb a sunny-day surplus.
Rule of thumb
| Situation | Go with |
|---|---|
| New system, no existing PV | DC coupling |
| Existing grid-tied PV the customer wants to keep | AC coupling |
| Want both new strings and to keep old PV | Hybrid — DC-couple new strings, AC-couple the legacy array |
Whichever you choose, the combined inverter capacity still has to satisfy AS/NZS 4777.2 and the DNSP export limit. Confirm against the installation manual for the specific model.
