From da22c6207367ea31c9596974fbcf1f0b711ee04c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Christian=20G=C3=BCdel?=
 <818878+cguedel@users.noreply.github.com>
Date: Sun, 9 Nov 2025 13:29:04 +0100
Subject: [PATCH] Planner: adjust session energy by initial value plan (#25149)

---
 core/loadpoint.go      | 4 ++++
 core/loadpoint_api.go  | 1 +
 core/loadpoint_plan.go | 2 +-
 3 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/core/loadpoint.go b/core/loadpoint.go
index ab9f99cb7..caa4b5904 100644
--- a/core/loadpoint.go
+++ b/core/loadpoint.go
@@ -148,6 +148,7 @@ type Loadpoint struct {
 	planTime         time.Time     // time goal
 	planPrecondition time.Duration // precondition duration
 	planEnergy       float64       // Plan charge energy in kWh (dumb vehicles)
+	planEnergyOffset float64       // already charged energy in kWh when plan was set
 	planSlotEnd      time.Time     // current plan slot end time
 	planActive       bool          // charge plan exists and has a currently active slot
 
@@ -514,6 +515,9 @@ func (lp *Loadpoint) evVehicleConnectHandler() {
 
 	// create charging session
 	lp.createSession()
+
+	// reset energy-based charging plan offset
+	lp.planEnergyOffset = 0
 }
 
 // evVehicleDisconnectHandler sends external start event
diff --git a/core/loadpoint_api.go b/core/loadpoint_api.go
index 46eb42035..b9d4e5273 100644
--- a/core/loadpoint_api.go
+++ b/core/loadpoint_api.go
@@ -368,6 +368,7 @@ func (lp *Loadpoint) setPlanEnergy(finishAt time.Time, precondition time.Duratio
 
 	lp.planTime = finishAt
 	lp.planPrecondition = precondition
+	lp.planEnergyOffset = lp.getChargedEnergy() / 1e3
 	lp.publish(keys.PlanTime, finishAt)
 	lp.publish(keys.PlanPrecondition, precondition)
 	lp.settings.SetTime(keys.PlanTime, finishAt)
diff --git a/core/loadpoint_plan.go b/core/loadpoint_plan.go
index 6a29c1f32..cf022a43e 100644
--- a/core/loadpoint_plan.go
+++ b/core/loadpoint_plan.go
@@ -37,7 +37,7 @@ func (lp *Loadpoint) finishPlan() {
 
 // remainingPlanEnergy returns missing energy amount in kWh
 func (lp *Loadpoint) remainingPlanEnergy(planEnergy float64) float64 {
-	return max(0, planEnergy-lp.getChargedEnergy()/1e3)
+	return max(0, planEnergy-(lp.getChargedEnergy()/1e3-lp.planEnergyOffset))
 }
 
 // GetPlanRequiredDuration is the estimated total charging duration