Update README.md

README.md

@@ -3,6 +3,8 @@
 ### Official conversation group - https://groups.io/g/ATU100
 ### Schematic and assembly instruction by VK3PE - http://carnut.info/ATU_N7DDC/ATU-10/ATU-10_by-vk3pe_build_info/ATU-10_vk3pe_V1.2_ALL_INFO_290921.pdf
 
+###### AON FW is always on, no automatic power off. Use button to power off after using to avoid disgarging the battery.
+
 ###### New in FW version 1.5
 1 - Tuning algorithm improvement   
 2 - Minor changes