Forerunner 970 (fw 18.32): open device app with the Sensor permission drains ~1.5 %/h extra, even with no sensor calls

Device: Forerunner 970, firmware 18.32, SDK 9.2.0. No paired external sensors, Pulse Ox set to "during sleep".

Repro: one do-nothing watch app (blank screen, one-minute timer, logs battery every 5 minutes), built in variants that differ only in manifest permissions. Each was run worn for 1.5–3.3 hours with no input.

Variant	Permissions	Battery use
PNONE	none	≤ 0.6 %/h
PSENSOR	Sensor	1.9–2.1 %/h
PALL	Sensor, SensorHistory, Background, Notifications	2.25–2.7 %/h
PSQUIET	Sensor, plus `enableSensorEvents(null)`, `setEnabledSensors([])` and `disableSensorType(SENSOR_ONBOARD_HEARTRATE / SENSOR_ONBOARD_PULSE_OXIMETRY)` at launch	1.8–2.1 %/h; both `disableSensorType` calls return `false`
(no app open, overnight)	—	0.41 %/h

PSENSOR never calls any Toybox.Sensor function. Declaring the permission is enough to add about 1.5 %/h for as long as the app is open. The watch's battery page puts all of it under "Sensors & Accessories".

Expected: the Sensor permission alone, with no listener registered and no sensor enabled, should cost nothing extra. Or setEnabledSensors([]) / disableSensorType should bring the cost back to the no-permission level.

Impact: alarm and sleep apps have to stay open overnight (there's no unattended launch), so users lose 12–16 % a night.

Possibly related: "Venu 2S battery drain with the Sensor permission" (2021), and reports of Sensor-handler drain on the FR x55/x65 lines.

Fullscreen manifest.xml Download

<?xml version="1.0"?>
<iq:manifest xmlns:iq="http://www.garmin.com/xml/connectiq" version="3">
    <iq:application id="b687a2dd1287b8045c1dc63fcdb0de43" type="watch-app" name="@Strings.AppName" entry="ProbeApp" launcherIcon="@Drawables.LauncherIcon" minApiLevel="3.1.0">
        <iq:products><iq:product id="fr970"/></iq:products>
        <iq:permissions>
        </iq:permissions>
        <iq:languages><iq:language>eng</iq:language></iq:languages>
        <iq:barrels/>
    </iq:application>
</iq:manifest>

Fullscreen manifest.xml Download

<?xml version="1.0"?>
<iq:manifest xmlns:iq="http://www.garmin.com/xml/connectiq" version="3">
    <iq:application id="b687a2dd1287b8045c1dc63fcdb0de43" type="watch-app" name="@Strings.AppName" entry="ProbeApp" launcherIcon="@Drawables.LauncherIcon" minApiLevel="3.1.0">
        <iq:products><iq:product id="fr970"/></iq:products>
        <iq:permissions>
        </iq:permissions>
        <iq:languages><iq:language>eng</iq:language></iq:languages>
        <iq:barrels/>
    </iq:application>
</iq:manifest>

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