diff --git a/include/devices.h b/include/devices.h
index bb2068c..35acd0c 100644
--- a/include/devices.h
+++ b/include/devices.h
@@ -58,7 +58,7 @@ auto presenceTracker = Builder<BinarySensor>::instance(PRESENCE_SENSOR)
         .withParent(gatewayDevice))
     .withValueTemplate("{{ value_json.sensor.state }}")
     .addDiagnostic(new VoltageSensor{PRESENCE_SENSOR, "Battery voltage", "{{ value_json.sensor.diagnostic.voltage }}"})
-    .addDiagnostic(new BatterySensor{PRESENCE_SENSOR, "Battery level", "{{ ((value_json.sensor.diagnostic.voltage|float-2.5)|round(2)*100/2)|int }}"})
+    .addDiagnostic(new BatterySensor{PRESENCE_SENSOR, "Battery level", "{{ ((value_json.sensor.diagnostic.voltage|float-2.7)|round(2)*100/0.6)|int }}"})
     .withOffDelaySeconds(5*60)
     .withDeviceClass("presence")
     .build();