From a014175b09f2ac42933048ad52c40e963265eafd Mon Sep 17 00:00:00 2001
From: andig <andi@evcc.io>
Date: Mon, 6 May 2024 21:09:08 +0200
Subject: [PATCH] Load mangement: fix handling overloaded circuits (#13787)

---
 core/circuit.go      | 17 ++++++++---------
 core/circuit_test.go |  4 ++--
 2 files changed, 10 insertions(+), 11 deletions(-)

diff --git a/core/circuit.go b/core/circuit.go
index 7feab2d66..cab7c12e4 100644
--- a/core/circuit.go
+++ b/core/circuit.go
@@ -2,7 +2,6 @@ package core
 
 import (
 	"fmt"
-	"math"
 	"sync"
 
 	"github.com/evcc-io/evcc/api"
@@ -176,16 +175,14 @@ func (c *Circuit) updateLoadpoints(loadpoints []api.CircuitLoad) {
 
 func (c *Circuit) updateMeters() error {
 	if f, err := c.meter.CurrentPower(); err == nil {
-		// TODO handle negative powers
-		c.power = math.Abs(f)
+		c.power = f
 	} else {
 		return fmt.Errorf("circuit power: %w", err)
 	}
 
 	if phaseMeter, ok := c.meter.(api.PhaseCurrents); ok {
 		if l1, l2, l3, err := phaseMeter.Currents(); err == nil {
-			// TODO handle negative currents
-			c.current = max(math.Abs(l1), math.Abs(l2), math.Abs(l3))
+			c.current = max(l1, l2, l3)
 		} else {
 			return fmt.Errorf("circuit currents: %w", err)
 		}
@@ -246,8 +243,9 @@ func (c *Circuit) ValidatePower(old, new float64) float64 {
 	delta := max(0, new-old)
 
 	if c.maxPower != 0 {
-		if c.power+delta > c.maxPower {
-			new = max(0, new-(c.power+delta-c.maxPower))
+		potential := c.maxPower - c.power
+		if delta > potential {
+			new = max(0, old+potential)
 			c.log.DEBUG.Printf("validate power: %gW -> %gW <= %gW at %gW: capped at %gW", old, new, c.maxPower, c.power, new)
 		} else {
 			c.log.TRACE.Printf("validate power: %gW -> %gW <= %gW at %gW: ok", old, new, c.maxPower, c.power)
@@ -270,8 +268,9 @@ func (c *Circuit) ValidateCurrent(old, new float64) float64 {
 	delta := max(0, new-old)
 
 	if c.maxCurrent != 0 {
-		if c.current+delta > c.maxCurrent {
-			new = max(0, new-(c.current+delta-c.maxCurrent))
+		potential := c.maxCurrent - c.current
+		if delta > potential {
+			new = max(0, old+potential)
 			c.log.DEBUG.Printf("validate current: %gA -> %gA <= %gA at %gA: capped at %gA", old, new, c.maxCurrent, c.current, new)
 		} else {
 			c.log.TRACE.Printf("validate current: %gA -> %gA <= %gA at %gA: ok", old, new, c.maxCurrent, c.current)
diff --git a/core/circuit_test.go b/core/circuit_test.go
index 785ba1546..734049086 100644
--- a/core/circuit_test.go
+++ b/core/circuit_test.go
@@ -37,7 +37,7 @@ func circuitTests() []circuitTest {
 		{0, 2, 0, 1, 1, 0}, // =
 		{0, 2, 0, 2, 2, 1}, // =
 		{0, 2, 0, 2, 3, 1}, // +
-		// {0, 2, 0, 2, 1, 1}, // -
+		{0, 2, 0, 2, 1, 1}, // -
 
 		// parent loaded
 		{1, 0, 0, 0, 0, 0}, // =
@@ -52,7 +52,7 @@ func circuitTests() []circuitTest {
 		{2, 0, 0, 1, 1, 0}, // =
 		{2, 0, 0, 2, 2, 1}, // =
 		{2, 0, 0, 2, 3, 1}, // +
-		// {2, 0, 0, 2, 1, 1}, // -
+		{2, 0, 0, 2, 1, 1}, // -
 	}
 }