From f11cf690dc2f7fc243a6a67873a39eb61d93ef74 Mon Sep 17 00:00:00 2001
From: andig <andi@evcc.io>
Date: Sat, 4 Jul 2026 10:23:37 +0200
Subject: [PATCH] Vaillant: make hysteresis and reboost interval configurable
 (#31379)

---
 charger/vaillant.go                        | 77 ++++++++++++++++++----
 templates/definition/charger/vaillant.yaml | 19 ++++++
 2 files changed, 83 insertions(+), 13 deletions(-)

diff --git a/charger/vaillant.go b/charger/vaillant.go
index f477ee9b9..69971e7dc 100644
--- a/charger/vaillant.go
+++ b/charger/vaillant.go
@@ -19,6 +19,7 @@ package charger
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"reflect"
 	"strings"
@@ -27,6 +28,7 @@ import (
 	"github.com/WulfgarW/sensonet"
 	"github.com/evcc-io/evcc/api"
 	"github.com/evcc-io/evcc/api/implement"
+	"github.com/evcc-io/evcc/core/loadpoint"
 	"github.com/evcc-io/evcc/util"
 	"github.com/evcc-io/evcc/util/request"
 	"github.com/samber/lo"
@@ -41,6 +43,7 @@ type Vaillant struct {
 	*SgReady
 	log      *util.Logger
 	conn     *sensonet.Connection
+	lp       loadpoint.API
 	systemId string
 }
 
@@ -53,14 +56,17 @@ func NewVaillantFromConfig(ctx context.Context, other map[string]any) (api.Charg
 		System          string
 		HeatingZone     int
 		HeatingSetpoint float32
+		Hysteresis      float64
+		Reboost         time.Duration
 		Cache           time.Duration
 	}{
 		embed: embed{
 			Icon_:     "heatpump",
 			Features_: []api.Feature{api.Continuous, api.Heating, api.IntegratedDevice, api.SwitchDevice},
 		},
-		Realm: sensonet.REALM_GERMANY,
-		Cache: time.Minute,
+		Realm:   sensonet.REALM_GERMANY,
+		Reboost: 15 * time.Minute,
+		Cache:   time.Minute,
 	}
 
 	if err := util.DecodeOther(other, &cc); err != nil {
@@ -99,6 +105,45 @@ func NewVaillantFromConfig(ctx context.Context, other map[string]any) (api.Charg
 
 	wwCancel := func() {}
 
+	res := &Vaillant{
+		log:      log,
+		conn:     conn,
+		systemId: systemId,
+	}
+
+	// skipBoost reports whether the (re-)boost can be skipped because the measured
+	// temperature is already within the hysteresis band below the loadpoint limit
+	skipBoost := func() bool {
+		if res.lp == nil || cc.Hysteresis <= 0 {
+			return false
+		}
+
+		bat, ok := api.Cap[api.Battery](res)
+		if !ok {
+			return false
+		}
+
+		temp, err := bat.Soc()
+		if err != nil {
+			if !errors.Is(err, api.ErrNotAvailable) {
+				log.ERROR.Printf("temp: %v", err)
+			}
+			return false
+		}
+
+		limit := res.lp.GetLimitSoc()
+		if limit <= 0 {
+			return false
+		}
+
+		if hysteresis := float64(limit) - cc.Hysteresis; temp >= hysteresis {
+			log.DEBUG.Printf("temp: %.1f >= %.1f  hysteresis", temp, hysteresis)
+			return true
+		}
+
+		return false
+	}
+
 	set := func(mode int64) error {
 		switch mode {
 		case Normal:
@@ -114,8 +159,10 @@ func NewVaillantFromConfig(ctx context.Context, other map[string]any) (api.Charg
 				return conn.StartZoneQuickVeto(systemId, cc.HeatingZone, cc.HeatingSetpoint, 4) // hours
 			}
 
-			if err := conn.StartHotWaterBoost(systemId, sensonet.HOTWATERINDEX_DEFAULT); err != nil {
-				return err
+			if !skipBoost() {
+				if err := conn.StartHotWaterBoost(systemId, sensonet.HOTWATERINDEX_DEFAULT); err != nil {
+					return err
+				}
 			}
 
 			var wwCtx context.Context
@@ -127,7 +174,11 @@ func NewVaillantFromConfig(ctx context.Context, other map[string]any) (api.Charg
 					select {
 					case <-wwCtx.Done():
 						return
-					case <-time.After(15 * time.Minute):
+					case <-time.After(cc.Reboost):
+						if skipBoost() {
+							continue
+						}
+
 						if err := conn.StartHotWaterBoost(systemId, sensonet.HOTWATERINDEX_DEFAULT); err != nil {
 							log.ERROR.Println("hot water boost:", err)
 						}
@@ -142,18 +193,11 @@ func NewVaillantFromConfig(ctx context.Context, other map[string]any) (api.Charg
 		}
 	}
 
-	sgr, err := NewSgReady(ctx, &cc.embed, set, nil, nil)
+	res.SgReady, err = NewSgReady(ctx, &cc.embed, set, nil, nil)
 	if err != nil {
 		return nil, err
 	}
 
-	res := &Vaillant{
-		log:      log,
-		conn:     conn,
-		systemId: systemId,
-		SgReady:  sgr,
-	}
-
 	if devices, _ := conn.GetMpcData(systemId); len(devices) > 0 {
 		implement.Has(res, implement.Meter(util.Cached(func() (float64, error) {
 			res, err := conn.GetMpcData(systemId)
@@ -205,6 +249,13 @@ func NewVaillantFromConfig(ctx context.Context, other map[string]any) (api.Charg
 	return res, nil
 }
 
+var _ loadpoint.Controller = (*Vaillant)(nil)
+
+// LoadpointControl implements loadpoint.Controller
+func (wb *Vaillant) LoadpointControl(lp loadpoint.API) {
+	wb.lp = lp
+}
+
 func (v *Vaillant) print(chapter int, prefix string, zz ...any) {
 	var i int
 	for _, z := range zz {
diff --git a/templates/definition/charger/vaillant.yaml b/templates/definition/charger/vaillant.yaml
index cdf1626f1..658ebdb10 100644
--- a/templates/definition/charger/vaillant.yaml
+++ b/templates/definition/charger/vaillant.yaml
@@ -78,6 +78,23 @@ params:
     help:
       de: Notwendig falls mehrere Anlagen im Account vorhanden sind
       en: Required if multiple systems are present in the account
+  - name: reboost
+    type: duration
+    default: 15m
+    advanced: true
+    description:
+      de: Reboost-Intervall
+      en: Reboost interval
+    help:
+      de: Wartezeit, nach der Boost erneut gestartet wird.
+      en: Wait time after which Boost is started again.
+  - name: hysteresis
+    type: float
+    unit: °C
+    advanced: true
+    description:
+      de: Reboost Hysterese
+      en: Reboost Hysteresis
   - name: phases
     deprecated: true
 render: |
@@ -90,3 +107,5 @@ render: |
   {{- end }}
   heatingzone: {{ .zone }}
   heatingsetpoint: {{ .setpoint }}
+  reboost: {{ .reboost }}
+  hysteresis: {{ .hysteresis }}