From cc92f3938a9513b370033c271f9dba9452aa3a95 Mon Sep 17 00:00:00 2001
From: mggevaer <41551215+mggevaer@users.noreply.github.com>
Date: Tue, 18 Aug 2026 11:43:39 +0200
Subject: [PATCH] Fix site.pvPower estimation for battery without pv (#32930)

---
 core/site.go | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/core/site.go b/core/site.go
index d0a7e36b2..e558110a6 100644
--- a/core/site.go
+++ b/core/site.go
@@ -1054,9 +1054,10 @@ func (site *Site) sitePower(totalChargePower, flexiblePower float64) (float64, b
 		residualPower = 100 // W
 	}
 
-	// allow using grid and charge as estimate for pv power
-	if site.pvMeters == nil {
-		site.pvPower = totalChargePower - site.gridPower + residualPower
+	// allow using grid, charge and battery power as estimate for pv power
+	// needs a grid meter, otherwise grid power is itself derived from pv power (see above)
+	if site.pvMeters == nil && site.gridMeter != nil {
+		site.pvPower = totalChargePower - site.gridPower - site.battery.Power + residualPower
 		if site.pvPower < 0 {
 			site.pvPower = 0
 		}