Support Articles

The FranklinWH system connects the AC PV inverter to the aGate unit via a built-in internal relay. This innovative design allows both new and existing legacy AC PV strings and compatible third-party PV inverters to be seamlessly integrated into the FranklinWH ecosystem.

In FranklinWH off-grid mode, the PV relay opens as a normal protective action to prevent system overgeneration and battery overcharging — this is not a system fault.

Main Reasons (FranklinWH Operating Logic)

1. Battery Full (100% SOC)

When the aPower battery reaches 100% SOC, the EMS opens the PV relay to stop non-smart PV inverters from overcharging the battery.

2. PV Generation Exceeds Load + Charging Demand (Overgeneration)

In off-grid mode, PV output is limited to match the total consumption of home loads plus battery charging power.

If PV power exceeds this balance (e.g., strong sunlight, low household load, high battery SOC), the PV relay opens to avoid overvoltage and overfrequency, and protect the inverter.

3. Grid-to-Off Transition Protection

When the grid loses power, FranklinWH prioritizes PV curtailment by opening the PV relay as a safety protection measure.

After a delay of several minutes, AC PV and DC PV will be restored to operation sequentially.

4. Non-Export String Compliance

For non-export PV strings configured per utility requirements (HECO CSS / NEM+, California NEM-MT), the PV relay remains open to fully curtail generation once the battery is fully charged. 

Working Mechanism

AC PV: The inverter adopts frequency-droop control. The PV relay opens automatically when excess PV generation causes grid frequency to drift too high.

Relay Reclosing Conditions

Key Summary

PV relay opening in off-grid mode is normal protective logic. It prevents system overvoltage, overfrequency, and battery overcharging damage.