Add support for 4-level Smart Grid (SG) control for heat pumps (Forced OFF / Normal / Recommended ON / Forced ON)

[ndemie]

Is your feature request related to a problem? Please describe.

EVCC currently supports Smart Grid (SG) control for heat pumps via two states: DIM and BOOST, resulting in three effective modes (dim / normal / boost).

Many heat pumps, however, support four distinct SG operating hookup patterns using two SG inputs (relays). A common pattern is:

• Forced OFF
• Normal operation
• Recommended ON (power-limited)
• Forced ON (no power limitation)

My heat pump (Daikin Altherma 3 GEO) is an example of this, but this pattern is common across multiple manufacturers.

With the current EVCC implementation, I can only reasonably map:

• DIM → Forced OFF
• BOOST → Recommended ON

This means the Forced ON / unlimited power mode cannot be utilized at all, even when there is extreme PV surplus or very low / negative electricity prices.

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Describe the solution you'd like

Add support in EVCC for an additional Smart Grid control level beyond the current DIM / NORMAL / BOOST model.

Important:
EVCC does not need to manage relay combinations directly.
A setup like Home Assistant can easily translate EVCC states into the required relay logic.

What would be useful from EVCC:

• An additional semantic control level (e.g. FORCED_ON, SUPERBOOST, or similar)
• Configurable thresholds to decide when this level is activated
• The ability to distinguish between:
  • Recommended ON (limited power)
  • Forced ON (unlimited power, aggressive buffering)

Example conceptual levels:

1. Forced OFF (DIM)
2. Normal (no SG signal)
3. Recommended ON (BOOST)
4. Forced ON (new level, higher priority than BOOST)

This keeps EVCC hardware-agnostic while enabling full use of SG-capable heat pumps.

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Describe alternatives you've considered

• Mapping BOOST to Forced ON, losing the Recommended ON state
• External automations outside EVCC that override behavior based on surplus

Both approaches work around the limitation but reduce clarity and EMS-level control.

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Additional context

• EVCC SG heating docs: https://docs.evcc.io/en/docs/devices/heating
• Many heat pump vendors implement SG using two binary inputs resulting in four operating modes
• Relay-level logic can be handled externally (e.g. Home Assistant), EVCC only needs to expose the additional control state
• Screenshot from a Daikin Altherma controller showing an example 4-level SG relay matrix (Forced OFF / Recommended ON / Forced ON):

[andig]

How would forced on map to evcc logic? Why would a heatpump not follow recommended on and need forced on in the first place?

/cc @premultiply

[ubieberich]

hi. My Rotex Heatpump has 4 states also.
SG 1 -> DIM
SG N -> Normal
SG 2 -> Target Temperature +5%
SG 3 -> Target Temperature 70°C

in SG 2 the power is limited to ~ 3 kW, in SG 3 it goes up to ~7 kW

so for the logic in EVCC :

• with enough PV Energy: load house battery, vehicle and Heating on mode SG 2
• with enough PV Energy, vehicle full, house battery full -> heating on Mode SG 3

[andig]

in SG 2 the power is limited to ~ 3 kW, in SG 3 it goes up to ~7 kW

This is apparently specific to your HP, so needs a specific implementation. The generic SGReady does not and cannot cover that.

And before that is added, it should be checked if your Rotex doesn't allow specifying power envelope which would be even more granular that mode 2/3 selection.