Priorities¶

The priority list is the core of Hanergy's decision-making. It answers the question: when solar surplus is available, which devices should benefit from it, in what order, and to what degree?

The Waterfall Model¶

The priority list is an ordered sequence of entries, evaluated from top to bottom on every engine cycle:

1. Starting with the highest-priority entry (position 1), the engine checks whether surplus is sufficient and whether the entry's conditions are met.
2. If the entry can be activated, the engine allocates the required power and subtracts it from the remaining available surplus.
3. The engine moves to the next entry and repeats with whatever surplus remains.
4. Entries further down the list only receive power if everything above them has been satisfied or if surplus is large enough to serve multiple entries simultaneously.

Surplus flows from the top of the list downward — like water cascading through a series of buckets. Lower-priority devices only run if higher-priority devices are already running or already satisfied.

Priority Entry Fields¶

Each entry in the priority list links a device to a set of activation conditions:

Load Shedding¶

When surplus decreases — due to cloud cover, increased household consumption, or production dropping toward sunset — the engine sheds devices in reverse priority order: the lowest-priority active device is shed first, preserving the operation of higher-priority devices for as long as possible.

The shedding process works differently depending on device type:

• Dynamic devices are stepped down before being switched off. The engine first reduces the setpoint toward the minimum. If the reduced power still exceeds available surplus, the engine switches the device off entirely.
• Fixed and deferred devices are switched off immediately when shedding reaches their priority entry.
• The minimum on-time guard prevents a device from being shed if it was activated less than the configured minimum on-time ago. The engine skips it and continues to the next lower-priority device.

Multi-Level Priorities¶

One of the most powerful patterns in Hanergy is placing the same device at multiple positions in the priority list with different thresholds and setpoints. This expresses nuanced strategies: charge at a modest rate to meet a baseline target first, then charge at maximum rate to top up fully only when excess surplus is available.

Example Priority List¶

Consider a household with an EV charger, a home battery, a heat pump, and a pool pump:

Notice that both the EV Charger (positions 1 and 4) and the Home Battery (positions 2 and 6) appear twice — each time with a different threshold and, for the EV, a different setpoint.

Walking Through a Typical Solar Day¶

Using the priority list above, here is how the engine behaves as production changes throughout the day.

Early morning — Production: 500 W, Surplus: 200 W¶

Surplus is below every entry's minimum. No devices activate. The household runs from solar production alone.

Mid-morning — Production: 2,500 W, Surplus: 1,600 W¶

The engine evaluates entry 1 (EV Charger). Surplus (1,600 W) exceeds 1,400 W and the EV SOC is below 60%. The engine activates the charger at 16 A (~1,380 W). Remaining surplus: ~220 W.

Entry 2 (Home Battery) requires 500 W — not enough remaining. Evaluation stops.

Late morning — Production: 4,500 W, Surplus: 3,200 W¶

Entry 1 is still active (EV at 45% SOC). The charger consumes ~1,380 W at 16 A. Remaining: ~1,820 W.

Entry 2 (Home Battery) requires 500 W — activated. Battery charges at ~800 W. Remaining: ~1,020 W.

Entry 3 (Heat Pump) requires 1,000 W — just satisfied. Heat pump activates at ~900 W. Remaining: ~120 W.

Entries 4-6 require more surplus than is available. Not activated.

Solar peak — Production: 8,000 W, Surplus: 6,500 W¶

Entry 1: EV has reached 60% SOC — satisfied. No power allocated. The engine moves on.

Entry 2: Battery at 78% — still active. ~800 W allocated. Remaining: ~5,700 W.

Entry 3: Tank at 52 °C — satisfied. Heat pump stops. Remaining: ~5,700 W.

Entry 4: EV at 63%, below the 80% threshold. Surplus (5,700 W) exceeds 3,000 W. Engine activates the charger at 32 A. Remaining: ~2,700 W.

Entry 5: Pool pump requires 800 W — activated. Remaining: ~1,900 W.

Entry 6: Battery at 78%, threshold 100%. Engine directs remaining surplus to battery charging.

Afternoon decline — Production: 3,000 W, Surplus: 1,200 W¶

Shedding begins in reverse order. Entry 6 (battery top-up) sheds first. Then entry 5 (pool pump). Then entry 4 (EV boost). The engine works back up the list, preserving higher-priority devices for as long as possible.

Threshold Behavior¶

A priority entry with a threshold is considered "satisfied" when the device's feedback entity reading meets or exceeds the threshold value.

Once satisfied:

• The engine does not allocate surplus to that entry.
• The device may still be active if a different priority entry (at a lower position) referencing the same device is active.
• The entry returns to "unsatisfied" if the feedback sensor drops below the threshold (e.g., the EV discharges overnight and the SOC falls below 60%), at which point the engine reactivates it on the next evaluation cycle.

Practical Tips¶