From dda8b56029ec3652e59a597c4d18dd65342c62ee Mon Sep 17 00:00:00 2001
From: "Jannis M." <58087069+jannismunz@users.noreply.github.com>
Date: Sat, 6 Sep 2025 00:11:09 +0200
Subject: [PATCH] Add support for my-PV AC ELWA-E (#23358)

---
 charger/mypv.go                             | 43 ++++++++++++++-------
 templates/definition/charger/ac-elwa-e.yaml | 24 ++++++++++++
 2 files changed, 53 insertions(+), 14 deletions(-)
 create mode 100644 templates/definition/charger/ac-elwa-e.yaml

diff --git a/charger/mypv.go b/charger/mypv.go
index 977662ae1..3a5999c8b 100644
--- a/charger/mypv.go
+++ b/charger/mypv.go
@@ -21,6 +21,7 @@ import (
 	"context"
 	"encoding/binary"
 	"fmt"
+	"slices"
 	"sync/atomic"
 	"time"
 
@@ -45,12 +46,13 @@ type MyPv struct {
 }
 
 const (
-	elwaRegSetPower       = 1000
-	elwaRegTempLimit      = 1002
-	elwaRegStatus         = 1003
-	elwaRegLoadState      = 1059
-	elwaRegPower          = 1000 // https://github.com/evcc-io/evcc/issues/18020#issuecomment-2585300804
-	elwaRegOperationState = 1077
+	elwaRegSetPower        = 1000
+	elwaRegTempLimit       = 1002
+	elwaRegStatus          = 1003
+	elwaRegLoadState       = 1059
+	elwaRegPower           = 1000 // https://github.com/evcc-io/evcc/issues/18020#issuecomment-2585300804
+	elwaRegOperationState  = 1077
+	elwaERegOperationState = elwaRegStatus // same register for elwa-e operation state
 )
 
 var elwaTemp = []uint16{1001, 1030, 1031}
@@ -66,6 +68,10 @@ func init() {
 	registry.AddCtx("ac-thor", func(ctx context.Context, other map[string]interface{}) (api.Charger, error) {
 		return newMyPvFromConfig(ctx, "ac-thor", other, 9)
 	})
+
+	registry.AddCtx("ac-elwa-e", func(ctx context.Context, other map[string]interface{}) (api.Charger, error) {
+		return newMyPvFromConfig(ctx, "ac-elwa-e", other, 2)
+	})
 }
 
 // newMyPvFromConfig creates a MyPv charger from generic config
@@ -194,20 +200,29 @@ func (wb *MyPv) Status() (api.ChargeStatus, error) {
 
 // Enabled implements the api.Charger interface
 func (wb *MyPv) Enabled() (bool, error) {
-	b, err := wb.conn.ReadHoldingRegisters(elwaRegOperationState, 1)
+	// "ac-thor" and "ac-elwa-2"
+	reg := elwaRegOperationState
+	enabled := []uint16{1, 2} // heating PV excess, boost backup
+
+	if wb.name == "ac-elwa-e" {
+		reg = elwaERegOperationState
+		enabled = []uint16{2, 4} // heating PV excess, boost backup
+	}
+
+	// register read
+	b, err := wb.conn.ReadHoldingRegisters(uint16(reg), 1)
 	if err != nil {
 		return false, err
 	}
+	state := binary.BigEndian.Uint16(b)
 
-	switch binary.BigEndian.Uint16(b) {
-	case
-		1, // heating PV excess
-		2: // boost backup
-		return true, nil
-	case
-		0: // standby
+	// determine enabled state
+	if state == 0 { // standby
 		return false, nil
 	}
+	if slices.Contains(enabled, state) {
+		return true, nil
+	}
 
 	// fallback to cached value as last resort
 	return wb.enabled, nil
diff --git a/templates/definition/charger/ac-elwa-e.yaml b/templates/definition/charger/ac-elwa-e.yaml
new file mode 100644
index 000000000..0d6c834cc
--- /dev/null
+++ b/templates/definition/charger/ac-elwa-e.yaml
@@ -0,0 +1,24 @@
+template: ac-elwa-e
+products:
+  - brand: my-PV
+    description:
+      generic: AC ELWA-E
+group: heating
+requirements:
+  description:
+    de: Für den Heizstab von my-PV ohne Display. Über das lokale Webinterface des AC ELWA-E muss der Wert für die "Zeitablauf Ansteuerung" auf einen Wert etwas größer der Intervall Zeit von evcc (z.B. + 5s) gesetzt werden.
+    en: For the heating rod from my-PV without a display. Use the local web interface of AC ELWA-E to set the value "Power timeout" to a value slightly higher (e.g. + 5s) than the interval time of evcc.
+  evcc: ["sponsorship"]
+params:
+  - name: modbus
+    choice: ["tcpip"]
+  - name: scale
+    type: float
+    default: 1
+    description:
+      en: "Scale factor for power limit"
+      de: "Skalierungsfaktor der Leistungsvorgabe"
+render: |
+  type: ac-elwa-e
+  {{- include "modbus" . }}
+  scale: {{ .scale }}