From 5e69a6226da49d9c6eeef7d2b190023e2f93dec6 Mon Sep 17 00:00:00 2001
From: andig <andi@evcc.io>
Date: Fri, 7 Aug 2026 17:47:30 +0200
Subject: [PATCH] pvnode: resample interval averages to power at slot start
 (#32604)

---
 templates/definition/tariff/pvnode-v2.yaml | 18 +++++++++++-------
 templates/definition/tariff/pvnode.yaml    | 18 +++++++++++-------
 2 files changed, 22 insertions(+), 14 deletions(-)

diff --git a/templates/definition/tariff/pvnode-v2.yaml b/templates/definition/tariff/pvnode-v2.yaml
index 89a417064..34ea67906 100644
--- a/templates/definition/tariff/pvnode-v2.yaml
+++ b/templates/definition/tariff/pvnode-v2.yaml
@@ -50,11 +50,15 @@ render: |
       type: bearer
       token: {{ .apikey }}
     jq: |
-      [.values[] |
-        {
-          start: (.timestamp),
-          end:   (.timestamp | fromdateiso8601 + 900 | todateiso8601 ),
-          value: (.pv_power | round )
-        }
-      ] | tostring
+      # values are the average power of the 15min interval ending at the timestamp.
+      # evcc expects the power at the timestamp, which is the mean of the intervals
+      # meeting there- the trailing interval is dropped as its successor is unknown.
+      [.values[] | {t: (.timestamp | fromdateiso8601), v: .pv_power}] as $s
+      | [ range(0; ($s|length)-1) |
+          {
+            start: ($s[.].t       | todateiso8601),
+            end:   ($s[.].t + 900 | todateiso8601),
+            value: ((($s[.].v + $s[.+1].v) / 2) | round)
+          }
+        ] | tostring
   interval: {{ .interval }}
diff --git a/templates/definition/tariff/pvnode.yaml b/templates/definition/tariff/pvnode.yaml
index 4d7e81518..62c51997f 100644
--- a/templates/definition/tariff/pvnode.yaml
+++ b/templates/definition/tariff/pvnode.yaml
@@ -54,11 +54,15 @@ render: |
       type: bearer
       token: {{ .apikey }}
     jq: |
-      [.values[] |
-        {
-          start: (.dtm | sub(" "; "T") + "Z"),
-          end:   (.dtm | sub(" "; "T") + "Z" | fromdateiso8601 + 900 | todateiso8601 ),
-          value: (.pv_watts | round )
-        }
-      ] | tostring
+      # values are the average power of the 15min interval ending at the timestamp.
+      # evcc expects the power at the timestamp, which is the mean of the intervals
+      # meeting there- the trailing interval is dropped as its successor is unknown.
+      [.values[] | {t: (.dtm | sub(" "; "T") + "Z" | fromdateiso8601), v: .pv_watts}] as $s
+      | [ range(0; ($s|length)-1) |
+          {
+            start: ($s[.].t       | todateiso8601),
+            end:   ($s[.].t + 900 | todateiso8601),
+            value: ((($s[.].v + $s[.+1].v) / 2) | round)
+          }
+        ] | tostring
   interval: {{ .interval }}