fix: reduce repeater battery polling

release-notes.yml

@@ -401,3 +401,24 @@ releases:
         area: docs
         text: "Updated the web panel, API, and custom CLI docs to cover the environment summary/trends, stats persistence behaviour, and existing T-Beam 1W fan controls."
     breaking_changes: []
+
+  - track: repeater-mqtt
+    version: "1.3.9"
+    tag: "repeater-mqtt-eastmesh-v1.3.9"
+    date: "2026-04-22"
+    previous_version: "1.3.8"
+    summary: "Reduced unnecessary repeater battery polling by removing hot-loop MQTT sampling and reusing throttled battery reads across stats and web status paths."
+    changes:
+      - type: fixed
+        area: mqtt
+        text: "Stopped rebuilding the MQTT status battery reading from a fresh ADC sample on every repeater loop iteration and switched that path to a throttled cached value instead."
+      - type: changed
+        area: stats
+        text: "Reused a single battery sample across the web stats history and summary builders so one logical stats operation no longer performs multiple immediate battery reads."
+      - type: fixed
+        area: board-support
+        text: "Reduced Heltec V3 battery-sense activity while MQTT and web features are active, while still keeping explicit status and telemetry requests on a fresh reading path."
+      - type: docs
+        area: docs
+        text: "Updated the custom CLI docs to note that repeater MQTT background battery sampling is now rate-limited while explicit status and telemetry requests still refresh immediately."
+    breaking_changes: []